Systems of Chemical Notation. 185 
Allow me, in the next place, to point out some observations 
on the fundamental part of the question under discussion. It 
presented itself before the Paris Academy of Sciences under 
two heads: the system of atoms, and the language or notation 
of atomic weights. You were right in separating these two 
things. I had tried to do the same thing, but with less dis- 
tinctness, in my last work, On Chemical Synthesis, in whic 
explained the system very fully, but without adopting it, and I 
said that the notation by atoms possesses certain advantages, but 
also some disadvantages. The discussion recently raised could 
not, in the nature of things, assume this methodical form; but 
I believe that I kept about the same ground, as I always said 
that the two languages expressed the same ideas in the same 
way, in most cases, except that special advantages belonged to 
each system of notation. Your conclusions seem to be about 
- the same as mine. 
The definition of equivalents, which you accuse me of not ° 
giving, was nevertheless presented during the discussion, and I 
will take the liberty of reproducing it: ‘ Equivalents express, 
in my opinion, the ratios of weight according to which bodies 
combine or substitute themselves for one another.” These 
ratios may be determined by the balance with infinitely as #4 
base with those of the sesquioxides. It is only in a subordinate 
way, and for the purpose of giving greater precision to chemt- 
cal analogies, which are often somewhat vague, that physical 
oduced, such as the gaseous density, 
t, the crystalline form, the molecular volume in 
the solid state, ete. 
