70 Proceedings of Boyal Society of EdinhitTgli. [dec. 19 , 
the separated hydriodate. The mass is then thrown on to a linen 
filter and thoroughly squeezed, then dried between blotting paper, 
broken up, and washed with benzol so long as the latter dissolves 
anything. The benzol is then removed by squeezing, drying on 
filter paper, and exposure of the pounded mass in vacuo. 
The hydriodate prepared by either of these methods is snow 
white, and tolerably permanent in air ; but if not carefully prepared, 
it rapidly becomes brown. Its purity was established by a deter- 
mination of iodine. 
The whole of the crystallised hydriodate (about 60 grms.) was 
placed in a separating funnel, and caustic potash added until the 
latter was nearly full ; the mixture was then shaken, when the 
hydriodate rapidly decomposed, and the phosphine separated as an 
oily layer which floated. It was then decanted and submitted to 
fractional distillation in a stream of hydrogen. The thermometer 
rose rapidly to 178°, then slowly to 190°. It was fairly constant 
from 180° to 182° when most distilled. Only a little passed from 
182° to 190°. Fraction 178° to 190° was redistilled. The ther- 
mometer rose at once to 177°, then rather more slowly to 178°. 
From 178° to 185° most distilled. The exact boiling point 
could not be fixed, but most of the liquid distilled from 180° 
to 183°. 
These experiments, conducted with the greatest care, and repeated 
two or three times, appear to indicate that monobenzyl phosphine 
suffers a slight decomposition at its boiling point, which lies some- 
where about 180° to 183° C. (uncorrected). 
Properties . — Monobenzyl phosphine is a colourless, highly re- 
fracting liquid, possessing a very characteristic and penetrating 
odour. Its smell remains for days on the hands after operating 
with it, and in one case the smell was observed months after an 
instrument had been handled by one of us for some time — the 
fingers having been previously in contact with a trace of the phos- 
phine. Exposed to the air, it at once fumes powerfully, and grows 
very hot. Its vapour, indeed, often inflames on unstopping a 
bottle containing it. Mixed with fuming hydriodic or hydrobromic 
acid, it gives a bulky crystalline precipitate of the haloid salt ; and 
it also, though with more difficulty, gives a hydrochlorate. 
Hydriodate . — This salt is easily formed either by subliming the 
