,")76 PROF. LETTS AND MR R. F. BLAKE ON 



with caustic baryta it is partly converted into the hydrate and partly into the tertiary 

 phosphine oxide, and toluol, 



(1) (C 7 H 7 ) 4 PHS0 4 + Ba(OH) 2 = (C 7 H 7 ) 4 POH + BaS0 4 + H 2 



(2) (C 7 H 7 ) 4 PHS0 4 +Ba(OH) 2 =(C 7 H 7 ) 3 PO + BaS0 4 +2H 2 + C 7 H 8 . 



Treated with carbonate of barium, the hydrate only is obtained — 

 (C 7 H 7 ) 4 PHS0 4 + BaC0 3 = (C 7 H 7 ) 4 POH + BaS0 4 + C0 2 . 



Normal Sulphate, {(C 7 H 7 ) 4 P} 2 S0 4 , 6H 2 0. — Obtained by decomposing a solution of 

 the chloride with sulphate of silver. It crystallises from a hot concentrated solution in 

 large rhombic plates. 



Nitrate, (C 7 H 7 ) 4 PN0 3 . — Long silky needles, soluble in water. 



Chromate, {(C 7 H 7 ) 4 P} 2 Cr0 4 ? — Obtained by double decomposition from the chloride 

 and chromate of silver. Small lemon yellow plates. 



Acetate, (C 7 H 7 ) 4 P(C 2 H 3 2 ). — Very soluble in water. 



Chlorate, (C 7 H 7 ) 4 P(C10 3 ). — Crystallises in long needles from a moderately con- 

 centrated solution. When heated it puffs. 



Picrate, (C 7 H 7 ) 4 P{C 6 H 2 (N0 2 ) 3 0} (Ledermann). — Obtained by mixing alcoholic solu- 

 tions of the iodide and picric acid ; the compound separating as the solution cooled in 

 beautiful yellow crystals. 



Hydrate, (C 7 H 7 ) 4 P(OH). — Obtained best by the action of carbonate of barium on a 

 solution of the acid sulphate. Very soluble even in cold water, and crystallises by slow 

 evaporation in beautiful rhombohedral plates sometimes half an inch long. The crystals 

 are transparent and highly refractive. The hydrate dissolves readily in alcohol, and the 

 crystals obtained from the solution contain alcohol of crystallisation, their formula being 

 (C 7 H 7 ) 4 P(OH),C 2 H 6 0. Solutions of the base have an alkaline reaction. They neutralise 

 acids with formation of salts of the phosphomum. When heated the hydrate decomposes 

 into the tertiary oxide and toluol, 



(C 7 H 7 ) 4 POH = (C 7 H 7 ) 3 PO + C 7 H 8 . 



The Bye Products formed in Hofmann's Sealed Tube Eeaction. 



In separating the benzyl phosphines from the products of Hofmann's sealed tube 

 reaction we obtained a considerable number of bye products, among which were the 

 following : — 



(A). A crystalline substance precipitated on addition of hydrochloric acid to the potash 

 solution which had been employed to extract the viscous mass containing tribenzyl 

 phosphine, &c. 



(B). A crystalline substance which separated spontaneously from the aqueous solution 

 obtained by treating the contents of the sealed tubes with water. 



((7). A crystalline zinc salt, also contained in the same aqueous solution. 



