J. M. Crafts on Ethers of Arsenic Acid. 17 
-water-bath, pure ether is added to the sone sta ey ae 
monia gas is passed through the solution ether in onder 
to precipitate the bromid of arsenic, which is 5 Snel with the 
arsenite of ethyl. The latter is separated from precipitate by’ 
___washing with ether, the ether is distilled in a water-bath, and 
| nally a current of dry air or carbonic acid is passed through. 
The residue consists of arsenite of ethyl containing some 
arsenious acid and bromid of sodium in solution. It can be 
purified completely by two or three carers Pure arsenite 
of ethyl boils at 165°-166° (no correctio 
nalyses were made of products obtained by the three 
methods of preparation described abov 
i ee ‘2320 grms. ; CO,=0 nee grms. ; H,0=01590 
i Sulstance=0 4960 ed G,0= wheat grms. ; te 0°3160 
ut 5 Shbebanesti0 ‘2510 gress - arseniate of magnesium and am- 
montum=\'2311 grms. 
The determination of arsenic was made by weighing the age 
stance in a bulb, breaking the bulb under a solution of 
caustic potash, oxydizing the arsenious acid by chlorate of 
potash and chlorhydric acid at a temperature of 50°, and pre- 
cipitating by sulphate of magnesium and chlorid of ammonium 
in the = nary way. 
IL III. Calculated for (OgHs)gAs Og. 
0=3438 — 84:33 eee 34-29 
= 761 708 ace 714 
s= . peace 36.34 35°71 
E  S8he daeusey of liquid arsenite of ethyl compared with that of 
_ water at 4°=1-224. 
; vapor density determinations were made at different 
. temperatures by Du method. 
‘ Difference ies the weights of the Sith orate on 
Temperature of the balance, 
Temperature of the oil-bath (air thermometer) = 9670 
Capacity of the bulb, =269°55 cc. 
Air sep = O5ac¢ 
Vapor density =7-389 Theory=7-2673 
The vapor density at 209 Pos ye 4 
213° 
“ “ 33° 119 
Am, Jour. Sct.—Seconp Seriss, Vou. L, No. 148.—Juxy, 1870. 
2 
