12 J. M. Crafts on Ethers of Arsenic Acid. 
to prevent decomposition. The distilling apparatus was pro- 
vided with an air reservoir and with a mercury guage, and the 
pressure was kept nearly constant at 60 millimeters during the 
course of the distillation. 
Arseniate of ethyl - eee at 148°-150° under a pressure of 
60 millimeters, 
About 4 of the bot aades quantity are obtained by the above 
method of prepar 
The arsenic ss ay are immediately decomposed by smallest 
traces of water and it is essential that the common ether use 
in their preparation should be abeslaiely anhydrous. It is also 
for the operation in the sealed tube, that it should 
contain no alcohol, since the iodid of ethyl acts upon alcohol 
with formation of ordinary ether and water. Ether can be mos 
easily freed from small quantities of water and alcohol by di- 
gesting it several times with shavings of sodium, which can be 
cut with a knife from a large piece, allowing it to stand each 
time 24 hours with the sodium, and then distilling. Ether so 
prepared can be heated with sodium to 90° in a sealed tube 
without the Baallest evolution of hydrogen. 
The following analyses were made of arsenite of thes dis- 
tilling at 148°-150° under a pressure of 60 millim 
i. Lee oe = 02980 grms. ; CO, = 03470 grms.; H,O = 
174 
IL Substance = 0°9260 grms.; arseniate of magnesium and 
ammonium = 0°T705 grms. 
The determination of arsenic was made by decomposing a 
weighed quantity of the arseniate of ethyl by water, evapora- 
with nitric acid, and determining the arsenic acid as the 
arseniate of magnesium and ammonium on a weighed filter. 
Calculated for (CoHs)3 AsO, 
31°86 
6°64 
BGs oes 82-85 33°18 
The density of liquid arseniate of ethyl at 0° ie ge 
with that of water at 4°=1°3264. Its density at 8°8°=1-3161. 
The density of vapor of arseniate of ethyl - _ be taken 
on account of its decomposition by heat. omposition, 
owever, is not so great, but that its boiling int in the air 
can be determined with sufficient accuracy. pe a portion 
of the arseniate of ethyl, which has been patios by distillation | 
stil ter 
pepe diminished pressure, is distilled in the air, the greater 
abe f it passes at 235°-238°, but toward the last part of the 
illation decomposition ensues, and a white frothy deposit of 
arsenic acid is left in the retort. 
eniate of ethyl attracts moisture from the air and is im- 
sesiintoly decomposed with formation of arsenic acid and al- 
gE er eee 
