7 
of Chemical Equivalents. 
it is universal, and that in such analyses as are found not to 
accord with this general observation, we are warranted in 
suspecting some degree of inaccuracy in one or other of the 
results compared together. 
According to Mr. Dalton's theory, by which these facts 
are best explained, chemical union in the state of neutraliza- 
tion takes place between single atoms of the substances com- 
bined ; and in cases where there is a redundance of either 
ingredient, then two or more atoms of this kind are united to 
only one of the other. 
According to this view, when we estimate the relative 
weights of equivalents, Mr. Dalton conceives that we are 
estimating the aggregate weights of a given number of atoms, 
and consequently the proportion which the ultimate single 
atoms bear to each other. But since it is impossible in several 
instances, where only two combinations of the same ingre- 
dients are known, to discover which of the compounds is to 
be regarded as consisting of a pair of single atoms, and since 
the decision of these questions is purely theoretical, and by no 
means necessary to the formation of a table adapted to most 
practical purposes, I have not been desirous of warping my 
numbers according to an atomic theory, but have endeavoured 
to make practical convenience my sole guide, and have consi- 
dered the doctrine of simple multiples, on which that of atoms 
is founded, merely as a valuable assistant in determining, by 
simple division, the amount of those quantities that are liable 
to such definite deviations from the original law of Richter. 
Having some time since computed for private use a series 
of supposed atoms, I had assumed oxygen as the decimal 
unit of my scale, in order to facilitate the estimation of those 
