374 ODOROGRAPIIIA. 



ether or alcohol. He thus obtained a colourless liquid smelling 

 like peppermint, which decomposes on heating, and which, as 

 Erlenmever afterwards showed, is a mixture of normal ethyl- 

 sulphate and ethyl-isothionate, 



Ethyl sulphate was first obtained in a pure state by Claesson in 

 acting on alcohol with ethyl chlorsulphonate, CI — S O2 — C^ H.. 

 He also prepared it by the action of sulphuric acid on absolute 

 alcohol. If ice and then water be added to the cold mixture, and 

 the liquid shaken up with chloroform, the sulphate is dissolved 

 and left behind on evaporation. Ethyl sulphate is also formed 

 when silver sulphate is heated with ethyl iodide to 150^ C* 

 Claesson obtained a satisfactory yield in this way. He says, "Ethyl- 

 sulphate is a colourless liquid, insoluble in water, possessing a 

 pleasant peppermint-like smell. It boils at 208'^ C. with slight 

 decomposition, but may be distilled unaltered under diminished 

 pressure. At 19^ C. it possesses a sp. gr. of 1*1 83 7. It is only 

 very slowly decomposed by cold w^ater, but boiling water 

 decomposes it more or less quickly according to the amount present, 

 alcohol and ethyl-sulphuric acid being first formed." 



The U.S. Pharmacopoeia, 1880, indicates the proportions of 

 alcohol and sulphuric acid in the process of preparing oleum 

 mthereum to be as follows : — 24 parts by weight of alcohol, sp. gr. 

 0'820 ( = 26'26 by volume) and 54 parts by weight of sulphuric 

 acid, sp. gr. 1-840 ( = 29-34 parts by volume). These are the same 

 as those adopted by Dr. Squibb many years ago as a result of quite 

 an elaborate series of experiments : they are also the same pro- 

 portions used by Prof. Diehl.;]: In an experiment made by Prof. 

 Power, 500 c. c. of official alcohol and 500 c. c. of chemically pure 

 sulphuric acid were mixed, allowed to stand for 24 hours, and then 

 subjected to distillation in a flask of such capacity as to be nearly 

 filled by the liquid, and which was provided with a good condenser. 

 To the receiver a glass tube bent at right angles was attached, in 

 order to conduct the liberated and uncondensed gases into water 

 for their absorption. The first drops of distillate came over at 



* Ber. Deutsch. Chem. Ges., xi., p. 514. 



t Am. Journ. Pharm., 1857, pp. 192-204, and 1861, pp. 57-61. 

 t Ibid, 1865, p. 104, and Proc. Am. Pharm. Assoc, pp. 309-316. See also 

 papers by Prof. Maisch, Am. Journ. Pharm., 1865, pp. 100-105. 



