Dr. E. J. Mills on certain Cob alt amines, 259 



grm. 

 Also the amountofcobaltinthe ammoniochloride taken was 0*0900 



chloride „ 0*1350 



Total .... 0-2250 

 „ foundin the weighed precipitate was 0*2135 



The filtrate, which was colourless, yielded a brown coloration 

 with amnionic polysulphide, and contained 0*00846 grm. free 

 ammonia. The susceptibility of these mixed oxides to oxidation, 

 when prepared by the direct intervention of cobaltic chloride, is 

 again evinced in the composition of this precipitate, which, how- 

 ever^ contains the desired oxide in no higher state of oxidation 

 than that of the next degree (see equation at the foot of p. 257). 



The following experiment is important. 



0*13425 grm. hexammoniochloride, 0*0655 grm. cobaltic chlo- 

 ride, and 20 cubic centims. water were placed together in each of 

 three sealed tubes, and heated to 80°-100° for forty-seven hours. 

 [The cobaltic reagents are in the ratio 2(CoCl 3 . 6N H 3 ) : 2 CoCl 2 .] 

 Such part of the precipitate as could be collected weighed 0*19 

 grm. when dried at 65°; 0*1715 grm. of it gave 0*0092 grm. 

 water, 0*0259 grm. silica, and 0*2552 grm. cobaltic sulphate— 

 numbers which show that it had been almost wholly converted 

 into dicobaltic teroxide. 



Found. 



* . Co 2 3 



Cobalt . . 57-23"\ f 71-95 71-43 



Oxygen. . 22-31/^28*05 28*57 



Silica . . 15*10 



Water . . 5*36 



100*00 10000 100-00 



The nitrates were neutral, and contained the original sub- 

 stances together with sal-ammoniac. The filtrates from two of 

 the tubes were united, evaporated to dryness with a little hydric 

 chloride, and the cobaltic chloride extracted from the residue by 

 alcohol, and converted into 0*0382 grm. sulphate ; the residual 

 hexammoniochloride was transferred to a weighed filter and dried 

 at 100°; it weighed 0*1369 grm. An easy calculation, based 

 on these results, shows that the ammoniochloride and chloride 

 engaged in the reaction were to each other in the ratio 2 : 3*08, 

 which is in sufficient accordance with the ratio 2 : 3 already laid 

 down in equation (d) as the condition of obtaining a neutral fil- 

 trate. 



(3) When either of the polyammoniacal chlorides referred 

 to in this memoir is decomposed by water at 60°-120° under 

 pressure, the glass vessel employed is powerfully attacked. When 



