1908-9.] Life and Chemical Work of Archibald S. Couper. 199 
of Gerhardt and Williamson. I specially note this point, because Couper, 
in the new theory which he produced in the course of the next year, freed 
himself, at least partially, from these erroneous assumptions. 
Although Couper’s paper “ Sur une nouvelle theorie chimique ” * 
appeared somewhat later than his second and last experimental work, 
“ Recherches sur l’acide salicylique,” f I think it more convenient to con- 
sider Couper ’s theoretical views here. For it is not until the close 
of the paper “On a New Chemical Theory,” that Couper applies this 
theory to salicylic acid, whereas in the French paper on salicylic acid, as 
also in that on benzene, he uses almost exclusively empirical molecular 
formulae. 
In order to bring his work before his own countrymen, Couper 
published a full exposition of his new theory in the London, Edinburgh, 
and Dublin Philosophical Magazine and Journal of Science H e 
translated this paper into French, and, with some additions, published it 
in the Annales de chimie et cle physique .§ He also translated the paper 
on salicylic acid into English, applying his new theory to the formulation 
of the derivatives of salicylic acid discussed in it. This translation was 
printed in the Edinburgh New Philosophical Journal , 1858. || 
On Couper’s New Chemical Theory. 
As soon as Kekule, at that time Privatdocent in Heidelberg, saw 
Couper’s paper in the Comp>tes rendus, he brought forward his claims 
to the two most important propositions contained in it. Already, in the 
report of the meeting of the French Acadeni}^ on the 30th August 1858, 
we find Ivekule’s communication, “ Remarques de M. A. Kekule a l’occasion 
dune note de M. Couper sur une nouvelle theorie chimique.’T We shall 
therefore most conveniently follow Couper’s statements along with Kekule’s 
remarks on them. In this connection there came to my mind a remark 
which Kekule introduced into his speech at the celebration of the twenty- 
fifth year of the benzene theory, held in Berlin on the lltli of March 1890 : ** 
“ Some ideas at some time lie in the air : if one does not give expression 
to them, another will soon do so.” Or, as I may add in expansion, different 
thinkers often come independently and about the same time to proclaim 
* Comptes rendus, xlvi. 1157-1160. See Appendix to this paper, p. 237. 
t Ibid., xlvi. 1107-1110. See App., p. 266. 
X xvi. 104-116. See App., p. 240. § [3], liii. 469-489. See App., p. 241. 
|| viii. 213-217. See App., p. 267. "fT Comptes rendus, xlvii. 378-380. 
** Ber. d. Deutsch. Chcm. Ges., xxiii. 1304. 
