200 Proceedings of Royal Society of Edinburgh. [sess. 
When it is distilled under diminished pressure with great care, a 
liquid passes over which contains the primary phosphine, as well 
as some of the secondary body, and possibly a little tribenzyl- 
phosphine also. 
Our investigations on this very interesting and apparently extra- 
ordinary reaction are proceeding — the chief difficulty which we 
have to contend with being to obtain sufficient of the primary 
phosphine in a pure condition for the experiment. 
So far the results of our investigations show that — 
1. Hofmann’s “dibenzyl-phosphine” is undoubtedly the oxide 
of tribenzyl-phosphine. 
2. Dibenzyl-phosphine is probably a liquid combining easily 
with hydracids to give solid products of normal composition; 
oxidising in contact with air to form dibenzyl-phosphinic acid. 
3. Tribenzyl-phosphine is a solid crystalline substance combining 
with hydracids, and both with sulphur and oxygen at ordinary 
temperatures to form solid products. 
4. In Hofmann’s sealed tube reaction (i.e. } action of phosphuretted 
hydrogen on benzyl chloride) all the phosphines (as well as the 
quaternary compound) are obtained, and also all their possible 
products of oxidation (some of the latter may possibly not pre-exist 
in the crude product of the reaction, but be formed by subsequent 
treatment). Ia addition, other substances are obtained. The 
reaction is in fact highly complex, and is, we venture to think, 
extremely interesting, as it is certainly different from all similar 
reactions observed by Hofmann with fatty derivatives. 
5. Monobenzyl-phosphine is acted upon by crystallised iodide of 
benzyl at ordinary temperatures, and probably gives rise to free 
hydriodic acid, and to the secondary, tertiary, and quaternary 
compounds. If this be the case, the action is also comparable with 
that which occurs between ammonia and an alkyl iodide. 
Our researches on the above subjects have involved a large 
expenditure of time, energy, and material, and have been tedious 
and troublesome in the extreme. We have, however, the satisfaction 
of believing that the work, which has extended over several years, is 
nearly at an end, and we trust in a few months to be able to give a 
detailed account of the whole of our experiments to the Society. 
