304 BUNSEN ON THE CACODYL SERIES. 
once more distilled with concentrated hydriodic acid. The ice | 
which is mixed with the other crystalline body also affords a 
quantity of this iodide, but it is not so pure. It must be allowed 
to stand some days in contact with quicklime and chloride of 
calcium in a glass tube hermetically sealed and filled with car- 
bonic acid, to free it from water and the excess of hydriodic acid. 
It must then be distilled in the distillation tube filled with car- 
bonic acid. The iodide obtained in this way is a limpid yellow 
fluid, and has a most disagreeable irritating smell, very similar 
to that of chloride of cacodyl. It possesses a very high specific 
gravity, for chloride of calcium swims on its surface; it remains 
fluid at — 10° C. Its boiling point appears to be considerably 
higher than 100°, and yet it distils over with the aqueous vapour. 
The gas is yellow coloured, similar to that of hypochlorous acid. 
It does not smoke in contact with the air, but deposits very 
beautiful prismatic crystals on long exposure. These crystals 
are oblique four-sided prisms, truncated opposite to the edges of 
the smaller side. This form is connected with that of alcargen, 
as far as I could ascertain it without any accurate measurement ; 
and it might arise by lengthening the principal axis, and an 
increase of one terminal surface till the other disappeared. The 
iodide is soluble in ether and alcohol, but insoluble in water. 
Sulphuric and nitric acids decompose it, and disengage iodine. 
When it is heated in air it burns with a clear luminous flame, 
and the formation of fumes of iodine. It reacts with sublimate 
in the same way as the bodies already noticed. 
The first analysis was made with chromate of lead. 
I. 1:0095 grm. of substance yielded 0°373 grm. carbonic acid, 
and 0:235 grm. water. 
A small quantity of iodine passed over into the chloride of cal- 
cium tube; the second analysis was therefore made with oxide 
of copper. A small trace of iodine was perceptible in the chlo- 
ride of calcium. 
II. 1:3590 grm. of substance gave 0°5215 grm. carbonic acid, 
and 0°3160 grm. water. 
III. 1:1650 grm. of substance gave 0°4570 grm. carbonic acid, 
and 0°2735 grm. water. 
The iodine was estimated in the following way :—1‘284 grm. 
was dissolved in dilute alcohol and nitrate of silver added. The 
precipitate was gently warmed with nitric acid, and after heating 
to redness, weighed 1°317 iodide of silver. 
