590 
EESEAECHES OF DE. HOFIIAXX AXD :SL GAHOEES 
preceding paragraphs are repeated. The reaction, however, as might have been expected, 
is less powerful. 
The selenium-compound crystallizes from water with the same facility as the sulphur- 
compound, but the solution is apt to undergo partial decomposition when exposed to 
the atmosphere. Even the dry crystals are slowly reddened in the air. The fusing- 
point of the selenide is 112° C.; it is easily volatilized, undergoing partial decomposition. 
It contains 
C,,H,PSe,=E3PSe,. 
In analysing this body, we have availed ourselves of the ready decomposition which 
it undergoes by nitrate of silver, when dissolved in alcohol. 
0-378 grin, of the substance gave 0-557 grm. of selenide of silver. 
Theory. Experiment. 
r 2 '' 
1 equiv. of Triethylphosphine . . . . 118 59-9 
2 equivs. of Selenium 79 40-1 39-45 
1 equiv. of Biselenide of triethylphosphine 197 100-0 
In order to give more completely the history of the phosphorus-bases, we have also 
examined the compounds which are formed by the action of the iodides of methyl 
and amyl upon triethylphosphine ; but since the products of these reactions resemble in 
every respect the corresponding ethyl-compounds, we have only to mention the analytical 
results. 
Iodide of MetliyltriethyJphosplionium. 
In treating triethylphosphine -with iodide of methyl, all the phenomena mentioned in 
the case of the analogous experiment ivith iodide of ethyl are repeated. The action is 
even still more violent and rapid ; and if no ether be added, a portion of the product is 
readily lost by the explosive effervescence of the liquid. The crystals thus obtained 
contain 
C,,H,PI=(MeE3)P I. 
0-544 grm. of the compound, dried at 100° C., gave 0-491 grm. of iodide of silver. 
Tlieory. Experiment. 
. . . r ' 
1 equiv. Methyltriethylphosphonium . . 133 61-15 
1 equiv. of Iodine 127 48-85 48-77 
1 equiv. of the Iodide 260 100-00 
On treating the solution of this compound, which essentially resembles the simple 
ethyl-compound, with oxide of silver, a strongly alkaline solution of oxide of methyltri- 
ethylphosphonium is obtained. The solution, when saturated \ilth hydrochloric acid 
and mixed with bichloride of platinum, furnishes a beautiful orange-yellow platinum- 
