1888-89.] Prof. Letts and R. Blake on Dibenzyl- Phosphine. 197 
Hydro-bromate. — Obtained as the hydriodate : — - 
Obtained. Calculated for 
Bromine (1) 19 '5 2(C 7 H 7 ) 2 HP.HBr 
(2) 20-5 ) i 5 . 9 
(3) 16-3 \ 10 y 
Nitro- Compound. — Obtained by dissolving 
fuming nitric acid, and then precipitating wit] 
Obtained. Calcula 
fAVikTi TTnfm oTm ,ci x 
3(C 7 H 7 ) 3 PO. 2HBr 
14*44 
y the body in cold 
ti water. Amorphous. 
ted for 
Dibenzyl-Phosphine. ) (C 7 H 6 N0 0 ) 2 HP 
Carbon, 55 *23 55*26 
Hydrogen, 4*30 4*27 
Double Salt with Iodide of Zinc. — This co 
when fairly strong alcoholic solutions of tb 
zinc are mixed, in tufts of characteristic need! 
Obtained from 
(C 7 H 6 N0 2 ) 3 P0 
55*38 
3*95 
mpound separates out 
Le body and iodide of 
es. 
Hofmann’s Dibenzyl- 
Phosphine. 
Iodine, 26*57 
Calcula 
Oxide of Tribenzyl- Phosphine. 
I. II. 
26*0 25*9 
ted for 
3(C 7 H 7 ) 2 HP.ZnI 2 
Iodine, 26*43 
1 2(C 7 H 7 ) 3 PO.ZnI 2 
26*48 
4. Action of fused Potash on Hofmann's “ Dibenzyl-Phosphme .” — - 
In tbe paper by one of us and W. Wheeler already alluded to, 
the statement is made that when Hofmann’s dibenzyl-phosphine is 
heated with caustic, potash, or soda, “ it fuses and floats on the 
surface of the melted alkali. Ho violent action occurs, but on cool- 
ing the mixture and treating it with water the greater portion dis- 
solves, and acids then precipitate a flocky crystalline substance, 
which is dibenzyl-phosphinic acid.” In corroboration of this 
statement, the melting-point of the acid and analyses of its lead and 
barium salts were given, all in accordance with the required numbers. 
After we had satisfied ourselves that Hofmann’s dibenzyl-phosphine 
was oxide of tribenzyl-phosphine, and nothing else, this reaction 
recurred to our minds as a further and very striking excuse for the 
mistake we (and Hofmann) had fallen into, and we thought it of 
importance to verify the previous observation. This we have 
accordingly done, both with Hofmann’s dibenzyl-phosphine and with 
a specimen of oxide of tribenzyl-phosphine prepared by a different 
