HEINRICII ROSE ON ^THERIFIC A.TION. 377 



w hen distilled in a water-b:ith, at a temperature which need not 

 always amount to the boiling heat of water. It is not indeed 

 requisite to employ anhydrous alcohol, but the hydrated, of 90 

 j)cr cent. Tralles*, to obtain sether from a mixture at the above- 

 mentioned temperature. 



M. Wittstock had the goodness, at my i-equest, to institute a 

 series of experiments on this point, and communicated the re- 

 sults to me. 



I. Fifteen ounces of anhydrous alcohol were mixed in the 

 cold, with an equal weight of the hydrate of sulphuric acid, and 

 the mixture distilled at a temperature at which it could not boil 

 strongly. The products, well cooled, were successively received, 

 and the temperature at which they passed over accurately ob- 

 served. 



First product '. 1 dr. lOgrs., spec. gr. 0"817, 



passed over at from 60° to 80° R. 



Second j^roduct : 3 oz. 1 dr. 10 gr., spec. 



gr. 0-792, passed over at from .... 90° „ 93° „ 

 Third product : 3 drs. 5 7 grs., spec. gr. 



0*772, passed over at from 75° „ 80° „ 



Fourth ptfoduct : 2 oz. 40 grs., spec. gr. 



0-749, passed over at from 90° „ 95° „ 



Fifth product : 5 drs. 

 When the mixture had reached the temperature of 90° it 

 began to boil very slightly ; the boiling, howevei-, subsequently 

 ceased at this temperature, but even then aether was disengaged 

 from the mixture in bubbles, just as carbonic acid gas escapes 

 at the common temperature from a liquid strongly saturated 

 ' iwith it. 



j From these experiments it is evident that tether is formed 



Mat far lower temperatures than is usually supposed. The 



; first product smelt indeed strongly of ccther ; but chiefly con- 



' 'sisted, which is also indicated by the specific gravity, of alcohol, 



which had not been converted, by mixing with sulphuric acid, 



into sulphovinic acid; aether could not be separated from it, 



leither by water or even by chloride of calcium. The second, 



third, and fourth products consisted, on the contrai-y, principally 



of aether, which could even be separated by mere washing \\ ith 



* That is, 90 percent, absolute alcohol by volume; v.licii in Geiiiijiny it is 

 -ockonud by weight, IJichtor's scale is enijiloycJ. In Prussia alvJoliulumcUis 

 ii'tcr Tralles are euijiloyccl by the Excise. 



VOL. 11. PART VXI. 2 C 



