bouche à feu, pièce of ordnance, cannon, gun

Page 115. — 1. Sirius, the dog star, one of the brightest stars visible in the northern hémisphère, in the constellation of Canis major.

2. la Chèvre, Capella, a briiliant star in the northern constellation Auriga.

3. l'étoile polaire viendrait à s'éteindre, should the north star happen to be blotted out.

Page 116. — 1. M. Fizeau, a distinguished French physicist, born at Paris in 181 9. His experiments and discoveries regarding the velocity of light brought him very great honors.

2. Léon Foucault (1819-1868), a French natural philosopher, born at Paris; was fora time associated with M. Fizeau in researches upon the theory of light.

3. M. Cornu (Marie-Alfred, born 1841). He became professor of

physics at the Ecole polytechnique (Paris) in 1867, and has since then occupied himself especially with studies upon light. His représentative work upon the velocity of light first appeared in 1878. 4. tous, refers to progrès above.

Page 117. — 1. moindre d'un trentième environ de, about a thirtieth le s s than.