1908-9.] Life and Chemical Work of Archibald S. Couper. 217 
molecules of chemical compounds. Kekule still, at that time, made shift, 
if we may use the expression, with typical formulae. Although his 
ideas were no less clear than those of Couper, yet the formulae he used were 
still quite those of the type theory. He wrote glycollic acid : — 
O 
O 
deriving it from the double water type. Couper, as is clearly shown by 
his tartaric acid formula, would have written glycollic acid thus : — 
••••(>• OH 
V 0“ 
A O' ‘•'OH 
• -H 2 
and from this we at once get our present structural formula for glycollic 
acid : — 
C " OH 
. 0 
p " OH 
It was not until the spring of 1859 that Kekule, in the first part of 
his Lehrbuch , in remarks on the mutual union of atoms, gave his well- 
known graphic representation in which the basicity of the atoms is 
indicated by a difference in the size of their symbols — a difference in size 
which, as Kekule expressly says, is not intended to express any difference 
in the actual size of the atoms, but only the number of chemical units 
which an atom represents, that is, the number of hydrogen atoms to which 
it is equivalent. 
We have already become acquainted with Butlerow’s remarks on 
Couper’s new chemical theory. But before him, immediately after the 
appearance of Couper’s paper in the Annates de chimie et de physique, 
Wurtz expressed his views in reference both to Ivekule’s paper, “ Uber die 
Constitution und die Metamorphosen der chemischen Verbindungen und 
uber die chemische Natur des Kohlenstoffs,” * and to Couper’s “ Sur une 
nouvelle theorie chimique.”t His remarks were published in the Repertoire 
de chimie pure et appliquee , a journal he had just founded for notes on 
current chemical literature. The distinguished position of Wurtz, and his 
relation to Couper, make his criticism specially worthy of our consideration. 
* Rep. 20-24. t Rep. 49-52. 
H i 
C 2 H 2 0 j 
H 
