1908-9.] Life and Chemical Work of Archibald S. Couper. 233 
treatment of the fundamental principles of chemistry is unmistakable. 
His mode of thought is quite his own, his statements of his observations, 
supported by excellent analyses, are clear and definite. 
Is it not strange that such an investigator should have made no answer 
to the criticisms of his theoretical views by Kekule, Wurtz, and Butlerow; 
that he made no attempt to refute the doubts of Drion and of Kekule as 
to the accuracy of his work on salicylic acid ? But no further writing 
came from Couper’s pen. As a scientific man he had disappeared, and 
twenty-seven years had to elapse before the correctness of his statements 
as to the action of pentacliloride of phosphorus on salicylic acid was 
demonstrated by another. 
In the meantime, quite a number of chemists had busied themselves 
with the supposed salicyl chloride, mostly in order to study its action on 
other substances. Carius,* with the view of obtaining thiosalicylic acid, 
brought the undistilled product of the action of phosphorous pentacliloride 
on salicylic acid into reaction with an aqueous solution of excess of 
potassium sulphide. In Kolbe’s laboratory Glutz, f in 1867, showed that, 
by continued heating with a reflux condenser, for a day, of gaultheria oil 
with two equivalents of phosphorus pentacliloride, the latter ultimately 
completely disappears, and a better yield of chlorsalyl chloride is obtained. 
He states that, on distilling, after the phosphorus oxychloride has been 
driven off, the temperature quickly rises to 230°-260°, and that below 240° 
the distillate consists half of chlorsalyl chloride and half of salicyl chloride. 
Pierre Miquel J prepared “ salicyl carbimide ” by the action of undistilled 
“ salicyl chloride ” on metallic thiocyanates, and remarks : “ Le chlorure de 
salicyle s’obtient difficilement dans un etat de purete satisfaisant, il ren- 
ferme toujours des composes visqueux et retient avec beaucoup d energie de 
- Foxy chlorure de phosphore.” 
OH 
Otto Fischer, § in the same year, by heating “ the chloride C 6 H 4 qqqj , 
freed as much as possible from phosphorus compounds,” to 180° with 
dimethyl aniline and zinc dust in a current of carbonic anhydride, obtained 
the salicein of dimethyl aniline. 
Schreib, |j in 1880, states that in the action of phosphorus pentacliloride 
on salicylic acid only one molecule of the pentacliloride enters into 
reaction ; a second molecule is without effect and is recovered unchanged 
on heating to about 110°. He goes on to say : “ Bei weiterem Erhitzen geht 
* Liebig's Annalen , cxxix. 11 (Heft i., issued 8th Jan. 1864). 
t Ibid., cxliii. 194 (Heft ii., issued 20tli July 1867). 
J Annales de chim. et de phys. (1877) [5], xi. 304. 
§ Berl. Ber. (1877), x. 954. || Ibid . (1880), xiii. 465. 
