234 
Proceedings of the Royal Society of Edinburgh. [Sess. 
z u erst ein grosser Theil des gebildeten Phosphor oxy chloric! und spater Ortho- 
chlorbenzoylchlorid liber, bis sich, bei circa 260°- 270° der Retorteninhalt 
unter starkem Aufschanmen zersetzt.” 
From all these statements it will be seen that it is difficult to obtain 
Couper’s “ trichlorophosphate de salicyle ” from the product of the action 
of phosphorus pentachloride on salicylic acid by distilling under ordinary 
pressure. Contrary to Drion’s statement, the difficulties disappear, as I 
showed in the year 188 5 A when the distillation is conducted under 
diminished pressure. By working exactly according to Couper’s descrip- 
tion, with the materials he used, and distilling quickly, immediately after 
the reaction is finished, under ordinary pressure, “trichlorophosphate de 
salic 3 de ” is also obtained, although the yield is not so good. In the course 
of exhaustive investigations, carried out along with George Dunning 
Moore, we were able also to confirm Couper’s statements as to the “ mono- 
chlorophosphate de salicyle ” and the “ acide phosphosalicylique.” 
And thus, certainly late enough, there came a brilliant justification of 
Couper’s work on salicylic acid, work which chemists had gradually come 
to look on as so certainly inaccurate that no notice was taken of it in any 
of the treatises on organic chemistry. 
How often since then have I longed to know what became of Couper ! 
No doubt, there have been cases of English chemists who, after a 
meteor flash of one brilliant piece of scientific work, taken up by other 
engagements, have for many years been absent from the purely scientific 
field ; still, they have always attained a position which could not allow 
their names to be overlooked, not to say to be forgotten. It was otherwise 
with Archibald Scott Couper. He disappeared so suddenly and so 
completely from the scientific arena that there was not time for his name 
to gain entrance into the English, German, or French books of scientific 
biography. 
This enigma was completely solved by the investigations of his country- 
man, Alexander Crum Brown. It was not his disappointment that, by no 
fault of his, his paper, “ Sur une nouvelle theorie chimique,” was not pre- 
sented to the French Academy of Sciences until after the publication of 
Kekule’s famous paper, “ Tiber die Constitution und die Metamorphosen 
der chemischem Verbindungen und die chemische Natur des Kohlenstofls,” 
that broke Couper down, but a severe attack of illness. 
Having returned, late in the autumn of 1858, from France to Scotland, 
he obtained, in the end of December, the post of second laboratory assistant 
to the distinguished Professor Lyon Playfair, Edinburgh. 
* Liebig's Annalen, ccxxviii. 308-321 (Heft, iii., issued 18tli May 1885). 
