174 | Biography of Berzelius. 
the correct idea of that which is now universally called atom 1 
chemistry. Richter had previously employed in a similar sense the 
name relative mass (massentheil), in order to express the different 
quantities of acid and base which combine together forming salts ; 
his idea however, was not so material as that of Dalton, and 
this character was necessary to give it that perfect clearness, 
which was indispensable, if a theory was to be founded upon it. 
The long and obstinate opposition which was made by German 
philosophers to the idea of atoms as employed in chemistry, 
and the war waged with all the weapons of logical acumen 
against the atomic view of the composition of bodies, for a 
long time rather obstructed than favored the advancement and 
spread of the exact sciences, especially that of chemistry. Now 
that the atomic theory is adopted by all, the use of the word 
T'o Dalton, therefore, belongs the great merit of having given 
n 
atom is allowed by all in order to explain the facts with ease and 
simplicity. 
Dalton assumed that simple substances combined in equal 
atoms, and, indeed, atom with atom, when there was only one 
compound of the two elements; if several, one atom of one sub- 
stance combined with one, two, three, or more atoms of another. 
The first conception of these so-called multiple proportions origin- 
ated properly with Higgins, who made it known as early as 1789, 
in a work on the subject. But the most important experiments, 
by which the theory of Dalton was proved, were instituted by 
Wollaston, who published in the year 1814 his ingenious scale of 
chemical equivalents. 
When the numbers made use of by Dalton are compared with 
those which Berzelius deduced from his own accurate experl- 
ments, differences are found similar to those existing between 
these latter and those given by Richter. The number of analy- 
ses upon which Dalton had founded his arguments was too small, 
and moreover they had not been executed with very great ac- 
cu 
chemists have hesitated between hydrogen and oxygen. Dalton 
chose hydrogen, and took it as 1, since its atom is the lightest 
of all the elements. - Many chemists followed his example on this 
ie ito Se es aaa 
account, especially after Prout subsequently had attempted tO 
shew that the atomic weights of all simple bodies were multiples 
of that of hydrogen. Richter had long before entertained a si™- 
ilar view, inasmuch as he assumed that the equivalents of all ba- 
ses form an arithmetical, those of acids a geometrical progression 
Nevertheless, Berzelius and Wollaston took oxygen as unity be- 
cause it was the most widely distributed of all the elements, and 
