76 Proceedings of Royal Society of Edinhurgh. [dec. 19 , 
however, that although a very inert body yet under certain con- 
ditions, it does combine with the hydracids to form compounds, 
which, however, are unstable. 
Among other compounds it forms a very characteristic salt with 
bromine, and it also combines with chloride of platinum. 
Platinum Salt . — On mixing alcoholic solutions of chloride of 
platinum and dihenzyl phosphine a light yellow crystalline powder 
is produced, hut its composition varies considerably according to the 
conditions under which it is prepared, as the following analyses 
show : — 
(A) 
(B) 
(C) 
Carbon, 
. 59-5 
56-6 
58-5 
Hydrogen, . 
. 5-8 
5-3 
5-9 
Platinum, . 
. 12-8 
13*1 
13-1 
(A) Prepared by mixing cold alcoholic solutions of chloride of 
platinum and dihenzyl phosphine, and washing the product with 
alcohol until the washings were colourless. 
(B) Prepared by mixing very dilute boiling solutions of the two 
bodies, and repeatedly boiling with alcohol. (The alcohol dissolved 
a colourless body.) This product was very crystalline, and of a 
full yellow colour. 
(C) Prepared as (B), but washed with cold alcohol. 
It is probable that the products are loose compounds of chloride 
of platinum and dibenzyl phosphine. The nearest formula for A is 
5{(C7H5-)2HP},PlCt^, which requires 
Carbon, 
59*5 
Hydrogen, . 
5*3 
Platinum, 
14-0 
Action of Hydrol)romic Acid on Dibenzyl Phosphine . — An 
aqueous solution of hydrobromic acid is without effect on dibenzyl 
phosphine, but if the latter is dissolved in glacial acetic acid, and 
the mixture then saturated with hydrobromic acid gas, a crystalline 
precipitate falls, which usually redissolves as the solution grows 
warm, and subsequently, when the latter is saturated and has 
grown cool again, is deposited in small colourless crystals, which, 
when examined with the microscope, are found to consist of small 
but perfect plates. 
