C. Marignac—Chemical Equivalents and Atomic Weights. 89 
e tim 
totally invisible, although the sky remained clear. i 
The fact that the zodiacal light had been unusually brilliant 
and the aurora. The result of my observations of the zodiacal 
light and the aurora during the last seven years also seems to 
indicate some such connection, as when the zodiacal light was 
observed to be particularly bright, it has generally been fol- 
lowed by auroral phenomena. But only a long series of obser- 
vations in this direction can solve the problem. 
ridge, Nov. 2, 1877. 
. 
Art. XII. —Chemical Equivalents and Atomic Weights con- 
sidered as bases of a system of Notation; by C. MARIGNAC. 
(Translated from Moniteur Scientifique of Quesneville for September, 1877, by 
Mr. P. Casamajor.) 
THE Academy of Sciences of Paris has witnessed lately, at 
Several of its sittings, an interesting discussion, in which sey- 
eral eminent chemists, among its members, have taken part.* 
This discussion related to two questions which have often 
been brought before it, and which will probably be brought 
before it again many times. 
One subject of discussion was a principle, stated in 1811 by 
-* Messrs, Sainte Claire Deville, Wirtz, Berthelot, Fizeau. 
