THE CLIMATE OF MADEIRA

Funchal, Madeira, 1 June, 1854.

Deak Dk. Ltjnd,

I have undertaken to put down upon paper some of my ideas on the subject of Medico-meteorology, with référence particularly to the climats of Madeira. You, wlio know my taste for scientific pursuits, may probably imagine tbat I am much better qualified tlian I am, in fact, to furnish you with some valuable bints. In tbe first place, my knowledge of medicine and of diseases is as limited as is well possible, since it is confined to tbat wbicb I have unavoidably acquired during some years of expérience — not as a physician, but as a patient. Of this, however, you cannot be entirely ignorant. Secondly, wherever I have given my attention to medico-meteorological writings, I have been struck with what appears to me to be the extremely tmscientific manner in which the indications of meteorological instruments are dealt with, and this bas created in me. a distaste for the pursuit of a science which I can scarcely hope to advance. It appears to me, that the value and use of such indications are so imperfectly understood, that they have yet to be ascertaincd, by careful and laborious observations made in localitics the efTects of the climate of which, in originating, aggravating, and alleviating, particular diseases are known by independent means; but, that the gcnerality of persons who have ivritlen on the subject, scem to think that a few hygrométrie and thcrmometric data are sufficient to enable them to pronounce that a climate of long-cstablishcd réputation, whether good or bad, is in fact the

reverse of what was previously supposed. Moreover, it seems to be a matter of utter indifférence, that such data are often obtained from extremely defective instruments, observed by persons whose habits and pursuits bave not qualified tbem for the task ; and who can scarcely be supposed to have had sufficient leisure to enable tbem to dévote to it the degree of laborious and minute attention that it requires. But so it is, that persons who choose arrogantly to adopt and advocate any peculiar views upon a subject which is sufficiently obscure to admit of being so dealt with, and who are not seeking philosophically to investigate the truth, require only data upon which to found theu* arguments ; and, whether those data are true or false, is to them a raattcr of too littlc importance to be worth tlie trouble of investigation.

What the climate of Madeira really is, seems to be an interesting and much-disputed question. I fancy that the opinions of the médical men of the présent day, in England, are founded in great measure, either directly or indirectly, upon Dr. Mason's ïreatise on the Climate and Mcteorology of Madeira ; and that certain advocates of peculiar views have,by one-sided quotations, contributed, in no small degree, to make that book convey impressions very différent from what the author intended; — to say nothing of the high estimation in which Dr. Mason's observations seem to be regarded by those persons, and the very littlc crédit which is given to them here, not by médical men alone, but by ail persons whom l 'have heard speak of them, and wliose knowledge of meteorology in gênerai, or of Dr. Mason's observations in particular, render their opinions of any value.

The editor of Dr. Mason's book, page 199, suggests, that if visitors to Madeh-a would employ a part of their leisure in recording the state of the weather, the différence of opinion, now (1850) existing, as to the advantages or disadvantages of its climate, in certain cases of disease, would disappear. I cannot help thinking such records would contain a large mass of contradictory évidence, calculated to be useful to advocates of any views whatever, except the truth. The suggestion, however, is useful as an admission of the insufficiency of Dr. Mason's observations to settlc those différences of opinion. It also fui'uishes a remarkable instance of iniplicit and exclusive faith in meteoro-

logical data, as means of determining the effects of a climate upon diseases ; for the editor apparently does not think, that médical reports would be necessary or even useful adjuncts to such. records. The same gentleman (page 200) also suggests that the médical practitioners résident in the island can hardly allow the subject to be longer neglected, in the présent advanced state of science, without subjecting themselves to the reproach of indifférence, relative to the charge sometimes urged against them, of withholding the truth, under a dread that the farfamed climate of the island will not bear the test of close and accurate examination. Tliis reads to me something like charging a man vvith not looldng at his barometer on a fine day under a dread that its index will point to " foui weather." (And, by way of parenthesis, let me ask, why should the médical practitioners be charged with withholding that which is patent to every one who chooses to investigate the subject, and for which investigation the editor seems to think every invalid visitor is sufRciently well qualified?) But, in truth, we have long since learnt that those amusing little indications which instrument makers still continue to put into the mouth of the barometer, are not to be trusted; and I should have thought that, by this time, the hygrometer need not be similarly falsified. ïhe barometer is a very valuable instniment ; but, as has been justly observed, it has been brought into disrepute by the absurdity of engraving the words " fair, foui, wet, dry," etc., at différent parts of the scale ; and really one would suppose that some of our médical men are prepared to write the words " consumption, fever, choiera," etc., at différent points of the hygrométrie scale, and to prcscribc climates for their patients accordingly. And here I must quote from the AthenîEum for 1853, page 248, the following extract from a récent publication, by T. H. Burgess, M.D., 'which the Athenœum gives as the summing up of the author's expérience ; for this article has led to the présent discussion : —

" It results, from the preceding statements, that much misconception prevails with respect to the efficacy of foreù/n climates in cases of pulmonary consumption ; and, however agreeable to the sensés warm air, sunny skies, and luxuriant végétation may seem, they afford no proof of salubrity, nor of the bénéficiai

effects of any cliraate. Madeira, with ail its sanitary famé, is no exception to this rule, as the meteorological observations of Drs. Heineken, Gourlay, and Mason incontestably establish. Malta, etc., etc." — In the name of common sensé, how can meteorological observations incontestably establish any such fact ? Do tbe numerical readings of the barometer, hygrometer, etc., or the points of the compass towards which the wind-vane happons to point, afford proof of the salnbrity, or of the bénéficiai eff'ects of climate any better than what is agreeable to the sensés ? Taking this as a spécimen, I can easily believe that it does resuit frora the "preceding statements," referred to in the above quotation, that much misconception prevails somewhere ; for it seems that, because we are told that the hygi'ometers of the abovenamed observers gave certain numerical results, we must, without further inquiry, either respecting other facts, or as to the amount of crédit to be given to those statements, or whether the observations were gênerai or confined to particular localities, take it as a fact incontestably proved, that the climate of Madeira has not, and never had, that effect upon invalids which both the public and the médical profession attribute to it. And, strange to say, in order to arrive at this inconiestable conclusion, we must read those cabalistic numbers according to the interprétation of the author in question ; for no one else, not even the three meteorological observers themselves, who, be it remembered, were members of the médical profession, were able to discover that they conveyed any such meaning, as the following quotations fuUy show.

Dr. Gourlay* writes as foUows, except that I have underlined some words which, in the original, are not printed in italics.

At page 31, " The salubrity of the climate in this island, so highly extoUed, is greatly attributed to the uniformity of its température. A regular succession of land and sea-breezes, cool and purify its atmosphère during the whole year, and, especially, during the hottest months. Hence, a drop of dew seldom falls,

• Observations on the Natural History, Climate, and Diseases, of IMadeira, during a period of Eighteen Years. By 'William Gourlay, M.D., Fellow of tlie Koyal Collège of Pliysicians, Edinburgh ; and Physician to the British Factory at Madeira. London: 1911.

except in tlie higlier parts of the island ; and any deleterious effluvia, which may arise from the surface of the earth, or frora other sources, are dissipated as soon as they are produced."

At page 32, " During the day, the whole range of the thermometer will seldom, at any season, exceed two, or at most four degrees, and frequently, for several days together, the same degree of heat is indicated.

At page 33, " Where such uniformity of température exista, combined with purity of atmosphère, and where such a pleasing variety marks the climate, one would conceive that the inconveniences of seasons -would be unknown ; and that neither the excessive heats of summer would molest; nor the colds of winter pinch, the frame ; but it is found that this pleasing picture is not e7itirehj realised ; and though it may be truly said that, in gênerai, spring and autumn compose the whole year, yet it is not to be concealed that, during the months of July, Au^ust, and September, which are the hottest months, the heat becomes excessive and intolérable ; and that, on one or two occasions, the winter has been distinguished by a severe storm. Still, however, the winter may be said to be known only, perhaps, by a gale of wind, which may drive the vessels in the roads from their anchorage, or by a torrent of rain, which produces a rapid flow of the rivers down the ravines." It should be observed, that July, August, and September are not included in the Madeira season, that very few English invalida remain in the island during those months, and that those few usually remove to higher and cooler résidences during the heat of the summer.

At page 90, "Madeu-a, from its uniformity of temjjerature and purity of atmosphère, has long been, and still continues to be, the favourite retreat of consumptive patients from the northern parts of Europe. Here, the unhappy sufferers under this formidable disease cheat the ivi?iter of their own climate, and gain that cessation of suffering which such a situation is fitted to produce."

At page 92, aftcr describing the class of patients who had been ordered to Medeira, " Before such patients repair to this last haven of health, tlieir malady is unfortunately, in too many cases, in its last stage; when neither change of climate, nor any remedy whatever, can be of service. From what cause this back-

wardness to an earlier trial of a southern climate proceeds, is not for me to détermine ; but it would be well if the physicians of such patients were to recommend a change of température in the first stage of the malady, where, etc."

I have been unable to procure a copy of Dr. Heineken's meteorological observations, but the following extracts from a letter of his, dated Nov. 1826 (the sameyear as that in which his meteorological observations were published) and printed in the appendix to Mr. Lyall's book,* will answer my présent purpose.

At page 334, " Dr. Price estimated the expectation of a child at birth, in London, to be nineteen years of life, and Dr. T. Heberden, in Madeira, thirty-nine years. Without, however, stopping to inquire into the accuracy of thèse estimâtes, or the probable causes for their very great disproportion, allowing them to be correct ; it is certainly true, that Madeira is remarkably healthy : from most of the diseases peculiar to warm climates, it is exempt ; and many of those which in more northern latitudes, from the frequency of their occurrence, and épidémie or endémie characters, become a scourge, are here either altogether imknown or but slightly felt."

At page 337, " I shall take for granted, that my médical brethren in England will only advise those who are likely to benefît by climate to quit their native Shores ; and, with this proviso, I do not hesitate to say that Madeira holds out advantages that are not to be met with combined in any other quarter of the globe."

At page 339, " The température of Madeira is more equable (contrasting day with night, and summer with Avinter) than that of any other place. Our raina are violent, almost ti'opical ; but they are also periodical and circumscribed, and never lingering and teasing. We are entirely free from the piercing keen winds which are met with, more or less, ail over the continent of Europe, and enjoy, throughout almost the whole summer, althoughmore partially than between the tropics, "the trades" and land and sea-breezes which there prevail."

Dr. Mason says (page 37) : " The observations made at Sta. Luzia apply to that locality alone, and cannot in any way be made to suit the island generally ; nor will they give précise

* Eamblus iii Matleira ami in rorlugal. London : 1827.

information relative to the lower part of Funchal, ncar the sea, especially as regards the progress of humidity during the day, although, in point of température, they may be very near the

truth I may also reraark that almost every locality offers

something peculiar alike with regai'd to température, humidity, or the local winds which prevail; and that until a séries of observations shall have been made in différent localities, the full merits of the climate, as regards the suitability to différent diseases, or even stages of the same disease, will never be fully ascertained," etc. On the same page he states that invalids generally réside above the town, in the same line in which his observations were made. ïhis may have been the case some twenty years ago, when Dr. Mason wrote, but it is very différent now,

At page 133, Dr. Mason says : " From this statement (a long . one, which it is unnecessary to quote), we can account for the fact that patients who visit Madeira are so differently affected by the precisely same conditions of the atmosphère ; some experiencing relief, and others only an aggravation of their complaint. Accordingly the présent work will be regarded, not as an attempt to préjudice that island as a resort for invalids, but as an effort to point out the danger of an indiscriminate reliance upon the sanitary effects of its climate. Such a reliance is injurions. ïhe not unfrequently frustrated hopes of anxious friends, suggest advantages, real or imaginary, from a resort to other localities ; whereas the atmospheric phenomena of Madeira being ascertained, and the requirements of the patients found to correspond therewith, comparative uniformity of success would establish its réputation ; and the failure of cases to which its climate is not adapted, would not be attended with the effects of damaging its character as a résidence for those wh.o, by a change to such a locality, might reasonably calculate upon the realization of their most sanguine expcctations."

Again, at page 152 : "Those who, on their arrivai, find the leste agrées with tliem, had botter immediately remove to a dricr climate ; whilc those with ,whom it materially disagrees, as indicatcd by the symptoms which I have described, may rest assurcd that they will dérive permanent benefit from remaining, that their hopes will not be blighted, but that returning health

and strength will resuit from leaving for a season their own less hospitable climate."

At page 162, writing on the climate of London : " In its effects on the animal economy our summer season will approach to the Madeira climate, being slightly modified by température and hygrométrie condition."

Notwithstanding thèse opinions of Drs. Heineken, Gourlay, and Mason, it is now clearly ascertained, as we are informed by Dr. Burgess, that their own meieorological observations incontestably prove that the sanitary famé of Madeira is a pure delusion. The hieroglyphics which those gentlemen merely placed upon record have now been decyphered, and their meaning admits of no further dispute. It is ascertained, moreover, that Dr. Mason Avas mistaken in supposing that those which he found at Sta. Luzia Cottage were applicable to that locality alone.

The words "luxuriant végétation", in the extract which I. have quoted from the Athenœum, call for some remarks. The books which have been written on Madeira contain many statements on this point, which, without being more than commonly exaggerated, are calculated to entirely mislead a stranger as to the gênerai character of the island. So far as my knowledge extends, therc is scarcely a spot to be found where there is moisture sufRcient to support luxuriant végétation, without the assistance of artificial irrigation. Sir H. Davy, as quoted by Dr. Mason (p. 41), alludes to the grcat quantity of basaltic rock xmcovered by végétation. It is true that artificial irrigation is carried to a great extent ; nevertheless the more gênerai character of the surface of the country is dryness, barrenness, and absence of luxuriant végétation. Even grass for horses and cows is brought down daily from the mountains ; and in the summer, even on the mountains, the grass becomes so dry that a spark of fire will endanger the whole district. The whole island is of volcanic origin ; its surface is either précipitons, or very miich inclined, and the soil is of a porous nature. With the exception of a volcanic crater, and one or two other spots at distant parts of the island, none of which have I ever secn, I belicvc there are no hollows or basins capable of retaining water ; and those to Avhich I alludc as the exceptions, do so only for limited periods. I have never secn a lake or even a pond.

Thcre are some yam-grounds whicli, I should suppose, must be injurious to the health. of those persons wlio live on or close to them; but tbey are quite unworthy of furtber notice in this place.

The lestes of Madeira are sometimes niade great bugbears. "We may judge of Dr. Mason's opinion of tbeir importance to invalids, by the passage which I have already quoted, in which he advises those persons with whom the leste materially clisagrees, to remain in the island. With respect to his advice that those who, on their arrivai, find the leste agrées with them, had better immediately remove to a drier climate, I have to remark, that the season here is considered to begin on the Ist Oct., and to end on the 31st May. Now I arrived in the middle of September 1860, and it was not until some time in the foUowing June that I had an opportunity of judging of the effects of a leste ; and my expérience of lestes during the three succeeding seasons has not been much greater. The précise and strong symptoms which Dr. Mason describes as distinguishing thèse winds, may occur sometimes, for anything that I know to the contrary ; but most assuredly not always. It is not unfrequently a matter for doubt and différence of opinion, whether or not there is a leste ; and the strong symptoms which Dr. Mason describes, I have never witnessed in the course of four seasons and three summers.

The principal point in dispute respecting the climate of Madeira, is, whether it is dry or damp. Persons who judge of it by the test of their own feelings, use such expressions as the following : "The air is soft and delicious, and strikes with a peculiar charm the stranger, whom, perhaps, a few days have transfcrred from the gloom and chill of an English winter." " The dry and balmy air which produces this never-ending spring, makes the step buoyant, and raises the hopcs of the sufferer, who a few days before left the choking fogs, the rains and chilly damps, of the Thames and the Mcdway." Dr. Mason, howcver (page 33), says, " It would be a difficult task to convince many of the résidents that the climate is at ail damp, although the fact admits of being provcd in the most satisfactory and philosophical manner." Let us admit, for the présent, that Dr. Mason has proved in the most satisfactory and philosophical

manner that the air of Madeira is very damp, that is to say, damp in philosopliical language ; and let us suppose also, for the présent, tliat in philosophical language a damp air is one that contains a more than average quantity of moisture, the measure being the number of grains of water in a cubic foot of air ; for this, as I understand, is the manner of estimating the dampness of a climate to which Dr. Mason alludes. Are we to infer from thèse admissions, that persons who describe the climate, manifestly with référence to its effects upon the sensations, are labouring under a pure delusion ? Is it not obvious, on the contrary, that the sensation of dampness dépends upon something besides the number of grains of water in a cubic foot of air, and that Dr. Mason's satisfactory manner of estimating dampness fails todetect that not unimportant something, whatever it may be? Philosophers, in their arguments with the unlearned, frequently contrive to beg the question. So, in the présent case, Dr. Mason (or his predecessors, it is immaterial which) first appropriâtes the words dampness and dryness, and, by implication, defines their meanings to be in accordance with his method of estimating those qualities. Then, secondly, he has no difRculty in proving the ignorance and obstinacy of ail who persist in calling the air damp or dry, according to the original but less definite application of those words. And, thirdly, he absolutely ignores those différences in the state of the air Avhich are not indicated by his method of estimating it. Nevertheless, I do not believe it has ever been ascertained, nor does Dr. Mason assert, ihat dam^mess, as measured by his method, furnishes a truer criterion than our own sensations do, of the suitahiUty of a climate for animal life. His method has the advantage of being a definite and philosophical measure of something ; whilst the other is vague and uncertain. But the philosopher has no right to rest satisfied Avith his method. There are other qualities of air, of which we have sufficient évidence ; and it is his business to discover, define, and estimate them. It is most unphilosophical simply to ignore those other qualities, because they cannot, as yet, be dcfined or measured by any known instrument. Such distinctions as those to which I have just alluded would enter into theoretical spéculations, but would be of little practical importance, at présent, if medico-meteorologists would

always be content to deal fairly with the question. Dr. Mason tells us that his method of estimating dampness gives materially différent, nay contradictory résulta, when compared with. noninstrumental estimâtes ; but be does not fall into tbe error of appropriating to a damp climate, as estimated by his method, ail the ill effects which either expérience or préjudice bas attributed to dampness, as tested by the otber means. For this latter step we are indebted to other persons, wbo raise the cry of vapour, moisture, luxuriant végétation, dampness, etc., etc., in the ears of persons wbo are affected by a species of hydrophobia ; then appeal to Dr. Mason and other authorities, for certain facts which answer the intended purpose, and carefully suppress the opinions of those same authorities, as to the value of those facts and the inferences to be drawn from them.

Dr. Mason tells us (page 18) that the mean températures of the air of London and of Madeira are about 50° and 68° respectively, and consequently that, when saturated, the air of the latter contains twice as much moisture as the air of the former. Another inference, which we are equally at liberty to draw, is that the air of London, when absolutely saturated with moisture, is as dry as the air of Madeira when in a state of only halfsaturation. Now, people of ordinaiy understanding would certainly call the former excessively damp, and the latter excessively dry. Nevertheless, we must bow to our médical philosophers (not Dr. Mason, but others of more récent date), and not merely admit that, in such a case, there would be equal quantities of water in the air of both climates, but also that, so far as regards animal life in gênerai, and ail diseases in particular, which are usually considered to be much affected by dryness or dampness, the two climates are to be considered as on a par — that the air of London, when in a state of absolute saturation, is on a par with the air of Madeira in a state of half saturation ! Surely, this must be quite conclusive against the climate of Madeira, especially when we remembcr that a state of half- saturation corresponds to a dépression of the dew-point equal to about 18°, whilst Dr. Mason allows us (see p. 26 and table xxxii) a mean annual dépression of 7° at most. There is, however, anotbcr way of estimating the dryness or damimcss of air, wliich is equally well known to the ordinary metcorologist ; and I would

submit to your judgment whether it ought to be absolutely discarded in medico-meteorology. At moderate élévations, the air, Avhetber in England or in Madeira, seldom is absolutely saturated with moisture. Consequently, if we understand the comparison between the air of those two places when in that state, to mean nothing more than the words literally express, the fact is of no grcat value. Perhaps we are intended to understand that, as a gênerai rule, the air of Madeira would be twice as damp as the air of London. But, under the point of saturation, if the air of Madeira contains just twice as much moisture as the air of London, the former may still be considered, in another sensé, twice as dry as the latter; that is to say, it is capable of absorbing twice as much additional moisture. Consequently, there are two methods of comparing climates : one of which might enable us to pronounce that climate A is twice as damp as climate B ; ■whilst the other enables us to state just the reverse; and either ■would admit of bcing proved in a most satisfactory and phUosophical manner. Such of our médical men as may wish to prove that the climate of Madeira is a mere delusion, and to advise their patients indiscriminately to remain in England, may adopt the former method ; but they may perhaps find it conve- 'nient to be provided with the other, in case the question should be, a choice of résidence in England or in the polar régions, where, undoubtedly, the air contains a very small quantity of moisture ; since, if we take the average température of an extrême northern climate as high as 10° F., it will contain only onc-fourth part as much moisture as the air of London, both being saturated.

The observation which I have quoted at the beginning of the preceding paragraph, is a casual remark of Dr. Masou, to which he attaches no more importance than it deserves : and, consequently, I should not have thought that it required to be noticed, if I had not seen that it is misused by the manner in which it is quoted, misquoted, and re-q\ioted elsewhere.

I shall now proceed to make some observations respecting the accuracy of Dr. Mason's meteorological observations, and thcir value as gênerai results. I have learnt, from what I considcr sufRciently good authority, that, during his résidence in the island, Dr. Mason was several times absent from Santa

Luzia cottage, for many days if not weeks at a time. Indeed, he mites of having been at Santa Cruz. How his meteorological register was kept during those intervals, or by what process of calculation the blanks were fiUed up, we are not informed. We are only told, tbat he never for a moment deputed the task to any other person.

At page 1, he tells us that the height of Santa Luzia cottage, the placq^at which he made his observations, is 350 feet above the level of the sea, and at pages 82 and 83 it is stated at 300 feet. Having taken some pains to measure the height of my own house, which is only a few yards distant from Dr. Mason's house,

1 can state that the latter is less than 250 feet above the level of the sea, and not 350, or even 300 feet.

At page 2, he says the register-thermometer for external température in the shade, received the sun's rays ohliquely from

2 to 5 p. M. At least, I so understand the sentence. However, he probably meant, that the stone pillar against which the thermometer was placed was so exposed ; but either is very important : and, exactly what he means by the oblique rays of the sun, in this latitude from 2 to 5 p. m., and of course ail the year round, I am at a loss to understand.

At page 3, he tells us that the direction of the wind was determined by a vane, placed upon a high staff. It is true that the staff, which still remains, is nearly 8 yards long; but it stands so much below the level of my house, and other buildings in its immédiate vicinity, that I can only regard it as a useless toy. Even if the buildings were removed, the vane could be expected to indicate only the direction of the current of air in that part of the vaUey, and would be quite useless for gênerai purposes. I confess I am at a loss to point out any systematic method of registering the direction of the wind, in this mountainous country, which would be at ail satisfactory ; but I consider Dr. Mason's register of his own wind-vane as mere waste paper. One might as well register the flickerings of a candie in a room.

A more important question is, the value of Dr. Mason's hygrometrical observations. Santa Luzia cottage is a very small house. The room in which the hygrometer was placed opens towards the garden, which is much confined by high walls, especially near to the house. The room is supported upon stone pillars, with

an open area under it and for a little space in front of it ; the garden being two or tliree feet above the level of the area. Close to, and nearly on a level with the room in question, is an open water-tank, the vent of which leads into the area. ïhe leakage and waste water would naturally keep the area constantly darap, and, when I saw it, such was the case. An open watercourse, called here a lavada, runs across the garden at the distance of a few feet from the Windows of the room in question, and quite close to the area, in fact upon the low wall which forma the limit to the area on the garden side ; and this lavada, being two or three feet higher than the area, would tend to increase its dampness, both by surface-evaporation and by filtration. ïhe ' garden, I am told, was in a state of luxuriant végétation, and grew, amongst other things, bananas. When I visited the room, I immediately perceived a damp, mouldy smell, which I présume arose from the area and tank, under and in front of it. The foUowing is what Dr. Mason himself says with respect to the tank (see page 40). After speaking of the tanks kept to irrigate gardens, " I feel fully justified in attributing to those sources the effect of poisoning the air; as I sutfered severely in my own person ail the symptoms generally referred to the effects of marsh efïluvia — such as extrême lassitude, pains in the head and limbs, intolérance of light, mental dépression and anxiety, dry, parched, brown tongue, etc. — aU which disajDpeared in three days, without the aid of medicine, upon removing to Santa Cruz, a few miles from Funchal. On my return to Santa Luzia, the same symptoms re-appeared after a résidence of a few days, and continued, unabated, till this source of annoyance was partly removed, when some amélioration of the s5'mptoms took place. I have not the least doubt that they would have disappeared completely, could the stagnant water have been entirely got rid of ; but, although my landlord had lived some years in England, I had much trouble to convince him that water could be at ail offensive, after being kept two months in a tank."

From the latter part of this quotation it seems probable that, during a portion of Dr. Mason's résidence, the tank was in a worse state than it is at présent ; and this is somewhat confirmed by the description which the late Mr. Wilkinson gave me of it ;

since liis description is barely justified by the présent state of the tank. Mr. Wilkinson also told me that lie frequently remonstrated with Dr. Mason, on the absurdity of placing bis bygrometer in sucb a situation as the one he had chosen. On this point, howevcr, Dr. Mason says (page 3), "The hygrometer -was situated in a room to the west, between two Windows constantly open from 6 a. m. to 6 p. m., and very free from currents of air, as they acted like folding doors. This room was, consequently, free from local humidity arising from the evaporation of water from the ground, etc." Can anything be more absurd than to suppose open Windows, acting like folding doors, would exclude local humidity? What can be the value of hygrometrical observations with référence to the général climate of Madeira, which were dépendent upon sucli means of excluding peculiar local influences ?

At page 6, Dr. Mason says, " There is a striking coïncidence in the results afforded by Dr. Heineken's observations [made eight years before those of Dr. Mason] and my own, although the instruments by means of which they were obtained are so widely différent ; proving that when such observations are based on facts, instruments, however varied in their constructions, must offer, upon comparison, results which accord with one another ; because nature is uniform in her opérations ; whence the same causes invariably produce the same efFects." At page 203, the editor présents us with a comparison of Dr. Mason's and Mr. McEwen's observations made with similar instruments in the same months of difl'erent years, the latter giving upon an average somewhat more than double the degree of dryness stated by the former, and accompanièd by the foUowing remarks : " The différence of locahty, or the circumstance of his (Dr. Mason's) observations having been made in the lieuse, with open Windows, and mine (Mr. McEwen's) out of doors, does not sufïiciently explain the discrepancy, which I think fuUy proves — what Dr. Mason suspected — that the différent years vary niuch more than is generally admitted." How very consistent are thèse two proofs ! It may be as well to remark also that the results given by Dr. Mason, with respect to the mean annual dryness on the dew-point hygrometer (to use his own expression), at nearly the same hours of the day, are as foUows : Dr. Mason's,

7°.42 — Dr. Heineken's, 7°. 42 — a vei7 striking coïncidence certainly, since there is not a différence of even one-hundredth part or a degree. However, since Dr. Mason's observations were not made with the dew-point hygrometer, his resuit, when referred to the dew-point, dépends upon the factor of réduction which he employed. Now Dr. Mason employed a constant factor, without regard to the température of the air ; but if we emiîloy Mr. Glaisher's factor ( taking the température of the air between-65° and 70°, since it is stated in Table xxvii at 68°. 12) the results will stand thus— Dr. Mason's, 5°. 41— Dr. Heineken's, 7°. 42 — the latter being 37 per cent, greater than the former. I bave already pointed out, in the comparison of Dr. Mason's aifd Mr. McEwen's results, obtained with similar instruments, that the last is 100 per cent, greater than the first. Whethcr the facts on which thèse several results are based are erroneous, or whether nature bas deviated from the ordinary uniformity of her opérations, are questions which I shall leave for future investigation.

At page 31, Dr. Mason says, " In order to prove the dampness of the climate, I may instance the impossibility of keeping ii-on, in any form, from being rapidly oxydized. The différent powders, such as opium, squills, etc., soon lose their pulvérulent form, and become firmly united into a solid mass ; varions neutral salts rapidly deliquesce; gloves, shoes, etc., soon become covered with varions species of cryptogamous plants ; silks become spotted and unfit for use; pianofortes frequently require retuning; and the screws of various other instruments, as violins, guitars, etc., became so tight as to be almost immoveable. In fact, it would be impossible for végétation to fiourish, were not the atmosphère almost saturated with moisture ; as frequently, during the fine season, there is scarcely a shower of rain for three, four, and sometimes even six months in succession." To take the last statement first, I do not believe that végétation does or could fiourish, during such seasons as Dr. Mason describes, without artificial irrigation. It is somewhat remarkable, moreover, that Dr. Mason should speak of such long periods of drought, since, in his table vi, there is not one month in which rain did not fall on two days and two nights at least ; and, on those occasions, it rained during the whole of the two days, and only two hours

short of the whole of the two nights. The other facts I can easily imagine Dr. Mason really observed in his own house, since I have heard of similar occurrences in other houses : but I can make a counter^statement. I have now just completed my fourth season of résidence in a house which is the next above Santa Luzia cottage, and only a few yards from it. Gloves, boots, and silk handkerchiefs, kept in my own room during the whole of those periods, have never shown the slightest symptoms of becoming mouldy or spotted. I have a great number of iron and steel tools, which have remained constantly in another room, ever since my arrivai here nearly four years ago. Though I do fînd that the tendency of iron to rust is greater than I have observed in inland places in England, I much question whether it is at ail greater than at many sea-side places in England. Some of the polished steel tools, which have been kept nearly four years in the same room, without being either used or cared for, remain to this day without even a minute spot of rust, so far as I have observed from casual inspection. With respect to the statements that the screws of violins, etc., become tight, I should attribute such a resuit, not to the gênerai dampness of the climate, which I think could scarcely have that effect, but to the removal of the instrument from a dryer to a damper situation. The screws being properly tight when dry, might become almost immoveable when swelled by moisture. Consequently, it is easy to believe that the screws of violins, guitars, etc., always become fixed when taken into Santa Luzia cottage. Though I have not been in the habit of keeping a meteorological register, I have frequently observed the hygrométrie state of the air — not with great care nor with verj' good instruments. The results, however, when compared with Dr. Mason' s, are far from proving that " nature is always uniform in her opérations."

Admittbg that Dr. Mason's meteorological observations are entitled to more crédit than I give to them ; yet, in a paragraph which I have already quoted, we have his own statement that his results cannot in any way be made to apply to the island generally, and that, until a séries of observations shall have been made in other localities, the merits of its climate can never be fuUy known.

I cannot takc Icavc of Dr. Mason without alluding to ono

other circumstance. — A paragraph in the book to which I have already alluded has been pointed out to me by a lady. It mentions Dr. Mason's fate as " a telling comment on the blind credulity which prevails respecting the virtues of foreign climates in pulnionaiy consumption :" and then foUows a quotation from the editor's préface to Dr. Mason's book, ■which, I confess, does not appear to me to furnisli any sucli comment. But it is a melancholy and patbetic taie, and, since it seems to have touched the too sensitive feelings of the gentleman in question, it would be illiberal to flnd fault Avith his logic. Ncvertheless, he can scavcely complain, if I merely contribute a little more pathos, by quoting the very first paragraph of the same préface. It is as follows, exccpt that I have underlined some passages which, in the original, are not printed in italics. — " Apart from the value of Dr. Mason's work as affording a just estimate of a climate," (which, by the bye, both the author and the editor afterwards tell us it does not do) " the resort of a particular and large class of invalids ; his labours acquire an interest from the fact of their having been prosecuted in a state of exti-emely infirm health, rcgardless of the iiifluence which they must have had in aggravating the symjjtoms, and lessening the chance of recovery. He may truly be said to have sacrificed his life to professional seal. Contending with an extensive dérangement of the pulmonary functions, he resolutely cast aside ail solicitude for his ovm health ; and, without intermission or pause, completed a séries of difficult and fatiguing observations, with the noble view of rendering a benefit to society. The exposiire and privations which he would have imperatively prohibited a patient from encountering, he fearlessly and enthusiastically contended with in his own person ; undeterred by the most trying fluctuations of tanperature, the prostration attendant upon a constant strain of mind, and the watching which broke in upon that ordinary rcst which even the robust cannot forego without some degree of suffering. To none would he, for a moment, députe tho task which he had undertaken ; and, when ail • around him were cnjoying repose or courting it, this martyr, as he may be called, to meteorological investigation passcd the night with his instruments and journal, noting down the minutest changes which the atmosphère underwcnt, from the first sinking of the sun to

the first indication of its rising." Alas ! what a mclancholy instance is this of blind credulity respecting the virtues of foreign climates !

I do not wish the preceding remarks to be understood as indicating any opinions of my own, as to the sanitary effects of foreign climates in gênerai, or of the climate of Madeira in particular, with référence to English invalids. It is a question upon which I feel totaUy incompétent to form an independent opinion of any value. My object has been to expose the insufficiency of the grounds upon which other persons have arrived at conclusions which they have not hesitated to pronounce with so much self-coniîdence. I have not assertcd that their conclusions are false ; but I dispute the accuracy of the data, and the validity of the reasoning by means of which they profess to have arrived at those conclusions. Neither do I wish to assert, as a fact really ascertained, that Dr. Mason's cottage was so damp or so ill-chosen a place for hygrometrical experiments as some of my observations might seem to imply. It is sufficient for my purpose, if I have shown what I believe to be the fact, namely, that so much suspicion attaches itself to the value of his hygrometrical statistics, that no reliance ought to be placed upon them. Nevertheless, it may be as well that I should now state what my opinions are with respect to Madeira, if only for the piirpose of preventing a false inference being drawn from my silence on that point. In a few words then, my opinion is, that the climate is extremely bénéficiai in many cases. That the cases which are likely to dérive benefit from the climate can, in gênerai, be discriminated by the résident médical men; but that, owing partly to the effects of the climate being less well understood by médical mon résident in England, many invalids are sent here who had much better have remained at home. Moreover, there are two questions which ought to be carefully distinguished: the one, whether the climate is calculated to act beneficially on any particular disease ; and the other, whether it is advisable to send a particular individual who is afïiicted with that disease to this climate. For examjjle, the same author will tell us, on one page, what a mclancholy sight it is to see poor dcluded individuals seeking for health abroad, alonc, and away from their families and the comforts of a home ; and, on

unotlicr ptigc, of the foUy of individuals going to Italy in scarch of liealth, and spending their time in catliedrals, picture-galleries, theaties, ball-rooms, etc. : two somewhat contradictory représentations, if each is to be understood as applicable to the class invalid in gênerai ; both of which are, however, put forward as valid arguments against the abstract climate theory ; tliough the latter, so far as it is worth anything, furnishes an argument in its favour : for the same persons neither would nor could have spent their time so agreeably in Englnnd. That such excesses should induce greater evils than the climate can compensate for, is but too probable ; but such a resuit furnishesno argument against the climate theory. The abuses of climate, which are very fréquent and wcll known to résident médical men, are too often overlooked or not fully appreciated by médical men in England, when thcy have to consider the advisability of sending a patient abroad ; and also, when they attempt to form opinions respecting foreign climates, by means of the results to those whom they have sent abroad, and wlio, of course, are almost certain to conceal or misrepresent every imprudence of which they have been guilty. For myself, I have reason to think that I owe my life to the sanitary efFects of the climate of Aladeira. I do not, of course, forget the benefits which I have also derived from médical advice, and the strictness Avith Avhich I have always acted upon it.

I have expressed an opinion that the science of medico-meteorology is very imperfectly understood. I am not qualified, nor can I afford sufficient space to enlarge much upon this point ; but I shall, nevertheless, hazard a few observations, even at the risk of exciting the wratli of some pseudo-scientific members of your profession, who make many words, not in the spirit of scientific inquii7, but in that of arrogant dictation, upon a subject which, it is eAddent, they do not understand — which, in fact, is not understood by any one — and by them not sufficiently to enable thera to see their own ignorance.

I fully admit, as a gênerai rule, that the warmer the climate the greater is the quantity of aqueous vapour contained in a cubic foot of air. Is there any reason for doubting that this is a bénéficiai provision of nature ? In any given climate of limited extent, a particular spot which is more than ordinarily damp, as

measurecl by the proportion of aqiieoiis vapoiu- to common air, is iisually found to be unhcalthy. But if vve attempt to compare places situate in very différent latitudes by the same rule, it leads to results which are so preposterous that the method of comparison is obviously inapplicable. I do not believe the quantity of pure aqueous vapour in the air is a matter of nearly so much importance as it is generally supposed to be ; but, that many injurious effects upon the human system, -which are attributed to dampness, dépend, if not entirely, at least in great measure, upon other éléments. It may be that moisiure causes those other éléments to be developed, or that aqiieous vapour acts as their vehicle. It may be that the same causes often produce both dampness and those other éléments. On either of those suppositions dampness might be mistaken for the cause of the effects observed, especially when we have no précise means of dctecting any other cause to which they can be attributed ; and I cannot help thinking that such mistakes are frequently made. Can it be contended that the air of a close, dark, damp cellar is no more injurious to human health than equally damp air rendered so by fresh steam from a tea-kettle, or other similar means ? We know that over marshes miasmata sometimes exist to such an extent as to depopulate large districts, whilst a seaair, more than equally damp, is considered conducive to health ; yet no one doubts that the miasmata are caused by the moisture of the marshes. Though the existence of miasmata in marshy localities is fully recognized, their présence cannot be detected by any meteorological instrument, or even by chemical analysis of the air ; and consequently it is easy to believe that we cannot form correct estimâtes of the salubrity of air by any instrumental or cven chemical investigation of its qualities. I feel a strong conviction that many effects which are attributed to aqueous vapour alone, are, in fact, produced by other constituents, which frequently, but by no means necessarily, accompany it ; and that whether aqueous vapour is or is not accompanicd by those constituents, dépends upon the source from whence it is derivcd ; pcrhaps someAvhat in the same manner as watcr acquires différent qualities by filtration through différent minerai strata ; and that it is as great a mistake to attribute those effects to the aqueous vapour, n-^ if would be to attribute the pcculiar effects

of dififerent minerai waters to the one constituent water. A slight excess of aqueous vapour, if it happens to be derived from a poisoned source, may be a matter of great importance; and within a limited district, a slight excess of aqueous vapour at a particular spot, often does arise from such a source ; and, in other cases, it is an indication of want of free circulation of tKe air, and consequently of an undue accumulation of noxious vapours. But no such inferences can be drawn from comparisons of the quantities of aqueous vapours in the air of places at great distances from each other ; in which case the différence in the quantities of aqueous vapour is likely to be dépendent upon more extensive and essentially différent causes.

I do not mean to assert that aqiieous vapour is an unimportant élément in medico-meteorology ; but, until the many other éléments which enter into the question can be more certainly detected, and their effects eliminated, I think that hygrometry ^^dll be of very limited practical use. It must not be forgotten that there are many recognized meteors, such as electricity, ozone, and varions gases, which can be estimated, though with more or less difficulty, the effects of which upon the human system may be considérable, and that as yet very little is known about them. What Dr. Prout says in the appendix to the second édition of the eighth number of the Bridgivater Treatises, appears to me to deserve the attention of medico-meteorologists. I refer to his suggestions respecting the opposite effects of pure aqueous vapour, and of aqueous vapour in union with oxygen or deutoxide of hydrogen ; the affinity being apparently so slight, that this combination occurs only when the oxygen in the atmosphère exceeds the chemical équivalent, 1 of oxygen to 4 of hydrogen ; and that the results of every common analysis and examination of air are the same nearly as if such a state of combination did not exist. With respect to température, I have no remark to make, except that we must not lose sight of the fact, to which you will strongly testify, namely, that it is not merely the gênerai or average state of the air that détermines the salubrity of a climate, but that the amount and suddenness of the changes to which it is liable are most important points, especiaUy for invalids. Of course we ought also to take into account the iquestion, liow far particular changes, or injurious influences, necessarily

affect an invalid, and how far he may be protected from them by reasonable care. In which view of tlie matter, habituai heavy dews for an hour about sun-set, or even during the whole night, might be regarded as of no moment ; whilst a liability to sudden changes of température, or a hot sun and cold winds ^revailing during the day, would be extremely injurious. The equability of the climate of Madeira is, perhaps, one of its chief virtues. It would, however, be a mere delusion lo suppose that it is not liable to changes. There can, I imagine, be no place on the face of the globe which is not liable to changes, some more and some less than others. It would be equally a delusion to suppose that the climate of Madeira is a spécifie cure for consumption ; and wi'iters on climates might, perhaps, spare themselves the trouble of proving that it is not so. No sensible persbn, who imderstands what those words mean, can for a moment entertain such an idea. I must return to my startingpoint, and restate my opinion that, except in some extrême cases, the sanitary properties of climates can as yetbe determined only by their sanitary effects. For data of this description we are dépendent, in great measure, upon the opinions of médical practitioners, and none can be so good as those of the médical men résident at the place in question. Dr. Burgess may say, or, by quoting the editor of Dr. Mason's book, may imply, that the résident médical men being prejudiced and interested, their opinions are not to be trusted ; but, in so saying, he libels the profession in gênerai rather than the individuals in particular againet whom such observations are levelled. If we are to cast aside ail médical statements and opinions which are open to the samc objections, what have we left to trust to, and whom shaU we believe ? We are not, however, bound to accept either their assertions of facts, or their opinions, absolutely in the darlc. There are varions mcans of sifting évidence and ascertaining its value, and we are furnished with a great deal on the subject of climates which will not stand the test.

When I began this letter I had no intention of making fréquent référence to Dr. Burgess's book, which I had not read. By degrecs I have bccn drawn into an examination of the Madeira portion of the first chapter, comprised in ten pages ; and I must présent you with some of the fruits of my investigation.

At page 11, Dr. Burgess quotes from Mr. White a statement respecting the equability of this climate, and then tells us that Mr. White reluctantly admits that, although so very equable, the climate is not altogether free from changes, which constitute there, as elsewhere, the exciting causes of pulmonary affections. Mr. White's words are, "pulmonary and inflammatory affections", immediately foUowed by thèse words, which Dr. Burgess also oniits : " Thèse, however, as may be supposed, are comparatively rare among the better classes, and occur chiefly among the hard-working poor, who are more exposed to this cause and to sudden chills of the surface while perspiring profusely." Why did Dr. Burgess omit this sentence ? A little further on Dr. Burgess says : " Yet in this most perfect climate, the same writer informs us that the différent eddies or currents caused by the vicinity of the mountains, render either a vane or anemo • meter of little use." A wind-vane, or anemometer, in order to be of use, must be exposed to the wind ; the valley of Funchal is sheltered from the wind on the north, east, and west sides, and consequently thèse instruments are of little use. It is futile to employ instruments for the purpose of registering the direction or force of mere eddies and currents of air, which are to be found in every sheltered spot which is not too confined ; and the vaUey of Funchal has the advantage of being very extensive.

At page 12, Dr. Burgess m-ites : "It is also stated" (by Mr. White, I présume,) " that the position of his (Dr. Mason's) instruments was not well chosen"; and cooUy continues, "However, a summary of Dr. Mason's observations will enable the reader to form his own opinions as to their merits, and the reliance to be placed on them." I should have supposed that a reader who ^yished to form an opinion as to the reliance to be placed on the accuracy of meteorological observations, would find it necessary to examine them in détail, and not by means of a summary. Moreover, Dr. Burgess does not give us a summary of Dr. Mason's observations, but merely a few extracts from the editor's préface, and from the tcxt of Dr. Mason's work ; and with what degree of fairncss those extracts are made, I am about to show.

On the same page Dr. Burgess says : " Dr. Mason, who uUimatelyfell a victim to phthisis, went to Madeira with the belief that

he would recover his health under the alleged sanltary and benigU influence of tlie cliinate of that island." I should like to know upon what authority Dr. Burgess makes this assertion, for Dr. Mason's editor tells us that " his visit to Madeira, and conséquent résidence there for a period of nearly two years, were purely accidentai"; and then goes on to relate that Dr. Mason started for Nice ; that " this object, however, was unfortunately frustrated" by his disregard of self, and dévotion to a sick relative, and that he then came to Madeira ; that Dr. Mason afterwatds made a second attempt to reach Nice, " the climate of which, he had always been persuaded, was far better adapted to his case."

At page 13, Dr. Burgess quotes a paragraph from Dr. Mason respecting the hygrométrie condition of the climate of Madeira, in which he (Dr. Mason) asserts that it is saturated with moisture during the greater part of the year, and then proceeds as foUows (see page 14) : "The author (Dr. Mason) supports this statement by a séries of tables, from which it would appear that at the température of 50°, which is near the mean température of London, the air, if saturated, is capable of holding 100 parts of moisture in solution ; while at the température of 68°, which is rather above the mean température of Funchal in Madeira, it will contain 200, or nearly double what it is a,ble to hold in London." Judging by this paragraph, I présume that Dr. Burgess does not profess to have any knowledge of the science of meteorology ; for I cannot imagine that any person at ail acquainted with the rudiments of that science, could \vrite such a sentence. First, Dr. Mason (see page 18), does not state that the air of London is capable of holding 1 00 parts of moisture, except upon a previous supposition, which Dr. Burgess omits, and thereby converts that statement into unintelligible nonsense. Secondly, to represent the déduction as one which appears from Dr. Mason's séries of tables respecting the meteorology of Madeira, indicates a total misapprehension of the whole subject. Dr. Mason makes out his statement, not by his own tables, but by quoting from Mr. Daniel a physical fact in the science of meteorology. Thirdly, to suppose that Dr. Mason intendcd to prove, or even to support, his statement that the air of Madeira is saturated, by polnting out that if it îvere saturated it would contain twicc us much moisture as tlie air of London, is too ubsurd. Is

this a spécimen of Dr. Burgess's interprétations of meteorological observations, by virtue of wliich it is incontestably established that Madeira is no exception to the rule which he lays do^vn respecting ybm^jî climates ? Doubtless Dr. Burgess bas devoted his time to bis profession, its studies and its duties ; and, if be bas not found leisure to make bimself acquainted witb tbe collatéral science of meteorology, be is in tbe position of tbe majority of bis professional bretbren, and of otber professional men, wbo, for w«nt of time, must make some similar omissions. Tbis may be a valid excuse for bis misapprebension of Dr. Mason's statements, but liardly for putting them togetber in a manner wbicb is équivalent to gravely telling us tbat a certain quart measure is brim full, and siipporting tbat statement by référence to a séries of tables from wbicb it would appear that a pint measure, if full, is capable of bolding 100 parts of water, wbilst a quart measure will contain 200 parts, or double what a pint measure is able to bold.

Dr. Burgess, at page 14, writes, " By referring to tbe tables of Dr. Mason baving référence to tbis matter, it appears tbat tbe maximum dryness observed during tbe leste [the leste] is 22°.5," etc. Dr. Mason's statement, see page 26, is, " By referring to tbe tables, it will be seen tbat tbe maximum dryness observed during a leste, etc." [a leste]. And, at page 28, obviously witb référence to tbe same leste, or African hlast, as Dr. Burgess would bave us call it, Dr, Mason informs us that tbe dryness experienced during tbe strongest leste he had observed bad been eqiialled at Paris. I confess I was surprised to find tbat Dr. Burgess bad taken the trouble to examine Dr. Mason's tables, and to make déductions on his own account, but the mystery disappeared, wben I discovered that tbe wbole paragrapli to wbicb I bave just referred, and wbicb Dr. Burgess gives us as if it were bis own, was, in fact, copied from Dr. Mason's book, with tbe exception of an insignificant (?) substitution, of the for a. We bave other spécimens of insignificant mis-quotations.

Atpage 15, Dr. Burgess thus writes: " Tbe following observations witb référence to tbe variability of the weather at Madeira, will perhaps surprise the reader : ' Tbe very fréquent and remarkable variations, in a given séries of years, incontestably prove tbat Madeira is no more to be relied on tban any otber

place, for certainty of fine weather, and tliat it lias equally its anmial variations of température.' " Truly, the reader ouglit to be surprised, if lie gives crédit to Dr. Burgess' quotations, tliat such an extraordinary statement should be made by a person wbo bad resided nearly two years in tliis island. But bis astonisbment will, perbaps, take a différent direction, wben be is informed tbat Dr. Burgess bas eut oui ten words from tbe middle of tbe sbort paragrapb wbicb be bas quoted, and tbat tbose words reverse, or, at ail events négative, tbe meaning of tbe paragrapb as given above. Dr. Mason's statement, see page 35, is : " Tbe very fréquent and remarkable variations, in a given séries of years — pro^iding tbe ordinary observations of the inbabitants be strictly" [strictly'\ " correct — -incontestably prove, etc." And this foUows some remarks by wbicb Dr. Mason ridicules tbe manner in wbicb otber people bring forward tbe testimony of tbe oldest inbabitants to prove, tbat particular seasons were variations from ail former expérience, and tells us, in effect, tbat sucb testimony is not strictly correct. Consequently, Dr. Mason does not assert any sucb fact as tbat wbicb Dr. Burgess gives on bis autbority, and, professedly, in bis words. And wbat Dr. Mason does say, admits of being understood to iniply exactly tbe reverse. Are you surprised ? I am not.

At page 16, Dr. Burgess writes, " We bave already noticed tbat, during tbe prevalence of tbe leste, or sirocco of Madeira, tbe air is "excessively bot and parcbing. Witbin twenty-four hours after tbis wind bas ceased, tbere is a copions fall of rain ; and the autbor [Dr. Mason] bas observed a very strong précipitation of dew tbree hours afterwards; tbe tbermometer being reduced from 17° to 7° of dryness on tbe hygrometer, and at seven tbe foUowing morning, to 2°, while plants and sbrubs were covered witb dew. Thus we find, a few hours after tbe leste bas ceased, tbe whole atmosphère, from being intensely dry, becomcs surcharged witb bumidity." Of thèse tbree sentences, tbe first and last arc, I believc, Dr. Burgess's, and the middle one is an extract from page 48 of Dr. Mason's book, but witb tbe foUowing altérations. Dr. Mason says tbat rain generally falls witbin twenty-four hours after tbe leste lins altogether ceased, and be does not use the word co2noîis. Moreover, it happons that, exccpt on the mountaine, no rain foUowed the

particular leste to which Dr. Burgess has tlius called our attention, as will be seen by rcfemng to the extract from Dr. Mason's journal given at page 194. And this was, moreover, the strongest leste that occurred during bis résidence in tbe island. Further, in the course of my expérience, which is double that of Dr. Mason, np rain has followed any marked leste, within such a length of time as to connect the one phenomenon with the other ; and I have no recollection of rain having ever so followed any other leste, though I am aware that we are sometimes told by the inhabitants that it is to be expected.

With respect to the first and third sentences, which, as I have already stated, are Dr. Burgess's, they refer to the former statement respecting a leste — which Dr. Burgess has chosen to mite the leste — as if it were a fair représentation of wliat always, or at ail events usually occurs, when that wind blows ; though Dr. Mason, upon whose authority thèse statements are made, speaks of a leste, and refers to a table ( table xxv), in which he gives the maximum dryness of six lestes as follows : — J anuary, 9° ; February, 9°; March, 14°; June, 15°; October, 22°5 ; December, 13°. So fax •with regard to the fairness of Dr. Burgess's sélection of statistics. Now let us see how far even they bear out bis assertion, that the whole atmosphère, frora being intensely drxj, becomes SMrcharged with moisture. First, Mr. Glaisher tells us that, in England, the dew-point is sometimes 30° below the température of the air. Consequently, the fact that the wet bulb of the psycrometer was 17°, or even 22 1° below the température of the air during a leste, does not indicate a veiy extraordinary degree of . dryness ; since, if we take the température of the air at 8D°, the corresponding depi'essions of the dew-point, according to Mr. Glaisher's tables, are 25i-° and 33° respectively. Also, the corresponding quantities of aqueous vapour in a cubic foot of air arc 4.69 grains and 3.54 grains respectively; whilst the air of London, at the mean température of 50°, if saiiirated, would contain only 4.28 grains. Secondly — How does Dr. Burgess arrive at the conclusion that a few hours after the leste has ceased, the whole atmosphère becomes s^/7'charged with moisture ? Does he infer this from the fact that dew was precipitated, or frora the fact that the so-called Mason's hygrometer never shcwed a dépression of less than 2° ; which, according to his

table XXXII, corresponds to 4|° on the dew-point hygi'oraeter : for Dr. Mason does not say on the liygrometer, but on my hygrometer — a variation wldch, to Dr. Burgess, probably appeared immaterial. As to rain generally falling after a leste, supposing it to be a fact — what then ? We have in England heavy showers of rain — thunder-showers — within very much less than twentyfour bours after most oppressive beat. I must say tbat, so far as my expérience goes, I tbink our total exemption here from tbat oppressive electric state of tbe air wbicb, in England, often précèdes a tbunder-storm, fuUy compensâtes us for our occasional "African blasts." Lastly, I must add wbat Dr. Burgess omits to tell us, namely, tbat during tbe leste selected by bim as( a fair example witb respect to dryness, tbough it was tbe strongëst ever experienced by Dr. Mason (see p. 194), tbe maximum température of tbe air was 81° F., wbicb is less tban tbe maximum usually attained during tbe summer in some parts of England.

At page 17, Dr. Burgess says, " Madeira seems to bave no' more immunity from disease tban otber places. Dr. Heineken and Dr. Gourlay botb agrée tbat no disease is more common amongst tbe natives tban pulmonary consumption, and Dr. Mason corroborâtes tbat view." Dr. Heineken bas given an opinion wbicb I bave already quoted, tbat Madeira does enjoy mucb greater immunity from diseases tban otber places. Dr, Gourlay perbaps disagrees witb Dr. Heineken upon tbis point, since be enumerates several causes, peculiar to the natives, wbicb produce disease amongst tbem. How far tbese two pbysicians agrée witb respect to tbe prevalence of pulmonary consumption, I bave not tbe means of ascertaining ; but tbe foUowing extract from Dr. Gourlay, page 90, puts bis opinion in a somewbat différent ligbt. After referring to tbis island as tbe favourite retrcat of consumptive patients from tbe nortbern parts of Europe, be adds : " Yet still, tbougb so bigbly bénéficiai in tbis disease, witb tbe natives of otber countries, it is not to be concealed, tbat no malady is more prévalent bere tban pbtbisis witb tbe natives of tbe island," Why did not Dr. Burgess quote Dr. Gourlay' a opinion whole and entire, as be expresses it ? He migbt bave addcd, also, some extracts from tbe 5tb chapter of Dr. Gourlay's book, wbicb enumerates some of tbe reasons

(which might be greatly increased in number) why the natives are subject to disease — ^reasons wbich in no way apply to invalid visitors. Dr. Mason probably knew very little about the matter; and he only Tentures to say, that he should be inclined to corroborate Dr. Gourlay's opinion, tbat consumption and scrofula are fréquent in Madeira : M'hicb means, only, that he would do so if he could.

I must now apologise for some portions of this very long letter. In the course of writing it, I have been somewhat drawn aside from my original purpose, and I must now state that I by no means wish my numerous criticisms of one \vi'iter in particular to be taken as having any gênerai application, or as indicating my opinion of any other medico-meteorological writer whatever. I ought, no doubt, to révise what I have written, and render it more strictly consistent in its several parts ; but you know that I am on the eve of a voyage to England, after a very long absence, and cannot possibly find time to do so. For the same reason, I am compelled to omit some remarks which I intended to make on the great and pecuUar difRculties of making meteorological observations in this island as compared with England — partly with a view to point out how much must dépend upon the judgment and discrétion of the observer.

I shall conclude with one or two spécimens of reasoning, which appear to me to be more than commonly loose.

Of what value is the argument that, in the course of a few générations, the human System becomes acclimated, and therefore, that the climate in which an indiAddual and his ancestors have been born and lived, must be the best suited to that individual? Admitting this to be true as a gênerai rule, surely persons who are afflicted with organic disease may he the exceptions, and, whether they are or not, should be determined by observation not by theory.

Dr. Burgess thinks that it is inconsistent with the laws and opérations of nature that the country in which an individual was born, reared, and previously enjoyed good health, should be no longer suited for him when afflicted with organic disease. I suppose we must yield to Dr. Burgess what he appears to assume as a point too clear for dispute, namely, that tlic coimtry in which an individual was born, reared, and enjoyed good health doton

to a certain perîod, and then became affiicted loith organic diseuse, is thereby proved to have been, of ail climates in the world, the one which was best suited to bis constitution doiun to that period. Still I cannot belp thinking that anotber person wbo adopts as an à priori tbeory, that différent climates may not improbably be suited to the same individual in two totally différent states of bis bodily health, proves himself to bç possessed of an equally clear insight into the laws and opérations of nature, Secondly, I should like to be informed whether it can fairly be predicated of the generality of persons who are afflicted with organic disease, that they were born and reared in the enjoyment of good health, and totally unaffected by disease down to the period which the word reared may imply. Thirdly, if that is to be answered in the affirmative, are there not, at least, a great number of persons who are afflicted with organic disease from their birth, or during infancy, or at ail events befoie they reach the stage of life to which Dr. Burgess refers ? Fourthly, would it not tend to clearer conceptions of the matter, if such statements as the one which I have last quoted, were made in somewhat more logical form, so that we might see, without reading every sentence two or three times over, what are the promises assumed as the foundation of the argument, and understand the nature, value, and extent of the conclusion. I feel sure that no one who, placing some degree of confidence in the author, reads such an argument only once, and with ordinary attention, can have a just notion of the course of reasoning through which he is led, as it were blindfold, and consequently at the risk of being misled. Fifthly, since the author in question thinks, as he tells us elsewhere, that the laws and opérations of nature do not render it necessary for an invalid to be confined to the place in which he was born and reared, but that a proper locality should be selected within the limits of his own country, he ought to state whether England, Scotland, and Wales, are to be considered as one or as several. "We understand that it is distinctly prohi-, bitcd to an invalid native of Dover to cross over to Calais or Boulogne, and vice versâ ; but we are left somewhat in the dark whether the Tweed forms a boundary line in Dr. Burgess's médical map of climates. Apparently the charm lies in the adjcctive/ore?yn climatc ; but in a matter of so much importance to the public, the author ought to be more explicit.

With respect to Madeira, however, we have no reason to coinplain of want of explicitness. It is sulRciently obvions that Dr. Burgess regards it, in comparison \vith England, as an extrême climate. But upon what grounds ? We may présume that lie never placed himself Avithin reach of the " African blast", and consequently that ail bis information is drawn from other sources than Personal knowledge or expérience. Respecting the manner in wliich he interprets, understands, and represents those authors whom he cites as authorities, and from whom, it is fair to présume, he bas derived tbe principal part, if not the whole, of bis information, I need makc no further remark. I hope and believe that I have furnished you (not so much for your information as for your use) with better, fairer, and safer means of forming yoiu' own opinions of the merits, and of the reliance to be placed on bis book, so far as regards tbe climate of Madeira, than I should have donc if I had followed bis example, and merely given you, under tbe name of a summaiy, a few extracts from what he bas written on that subject, taking to myself, of course, as much liberty of interprétation and représentation as he bas tbought himself justified in making use of with référence to other authors.

Whatever benefits Madeira may confer on invalids, in the shape of change of climate, it is somewbat remarkable that most authors, except Dr. Burgess, dwell a good deal on its mildness, and speak of tbe benefit it confers by enabling invalids to avoid the extrême changes of our Englisb seasons ; or, as Dr. Gourlay expresses it, " to cheat tbe winter of their own climate". If, however, people imagine that the valley of Funcbal is a hothouse or a green-house, wbere even an eddy or current of air is not permitted to ruffle the leaves of a tender plant, they greatly deceive themselves ; foi-, tbougb we never have those severe, cold winds to which many parts of the Continent are liable, yet moderate breezes, amply sufRcient to renovate and purify the air, are by no means uncommon.

Believe me to be yours most sincerely,

J. M. BlOXAM.

George Lund, Esq., M.D.

T. IHOnAIlDS, 8", OBEAT QUEEN STllEET, LINCOLH's IKN.

CAPT. CHIOSSO'S RATIONALE OF GYMNASTICS.