184 Systems of Chemical Notation. 
served; and no absolute personal equation machine was avail- 
able. The officers were trained observers; and their distances 
greater will be the number of important facts developed ; and 
Mallet’s results and those here described to inaccuracy of obser- 
vation. Differences in the material traversed by the waves, and 
in the method of ubserving, may possibly explain them. If 
Mr. Mallet’s health will permit him to publish the details of his 
mode of observing, and to give the whole subject a general 
discussion, the paper will certainly find interested readers. 
Willet’s Point, N. Y. Harbor, Jan. 14, 1878. 
Art. XXIII.—On Systems of Chemical Notation. Letter of M. 
BERTHELOT to M. Marignac* (from the Moniteur Scientifique 
of December, 1877). 
has not been generall y accepted in France, it is because it has 
not succeeded, so far, in obtaining the good opinion of the 
majority of scientists; but, notwithstanding, imputations have 
not been spared that the partisans of equivalents are anima 
with a retrograde spirit. 
* An answer to the ae ; e 
Journal, February, ref igre tsemecag 2 Scientifique, September, 1877. (See this 
