6 Ta^-LO]<, Higher Oxide of Cobalt. 



their relation to each other, I have LjiVeii the ratio of 

 oxygen in each to one atom of cobalt. 

 C02O3 =CoOi,,o 



CO9O14 =C00ig,5 



COvOii =CoOi.57 



C012O19 = CoO, 58 (Bayley). 



CogOg =CoOi6o (Carnot). 



COgOls =C00i,;o „ 



C03O5 --CoOieB (Bayley, Schroder). 



CoOi-68 (Vortinann). 



CoOigs „ 



CoOo (McConnell and Hanes, Huttner). 



The probability is that all the oxides intermediate 

 between Co,0.. and CoO. are mixtures or compounds of 

 those two. Thus, CoyOs^Co.O,;, CoOo ; Co-0,i = 3Co.^O:i, 

 CoOo ; Co90i4 = 4Co.O:;, C0O2, &c. McConnell and Hanes 

 {loc. cit.) suggest that they are all — including, I suppose, 

 the sesquioxide — compounds of the monoxide with 

 the dioxide in varying proportions. 



Higher Oxides of Nickel. 



Many of the experimenters to whom I have referred 

 in connection with the higher oxides of cobalt, describe 

 very similar, and almost as many, oxides of nickel, mostly 

 produced by similar methods. I pointed out in my 

 former paper that nickel is also precipitated, as a black 

 oxide, by barium or calcium carbonate and bromine water 

 at a temperature of 80*^ — lOO" C. I have made numerous 

 experiments to try and find the composition of the oxide 

 thus precipitated, but have been unable to obtain any 

 uniform results. The composition of the oxide varies 

 between somewhat wide limits, depending on the time of 

 heating, the amount of bromine water used, and whether 

 the bromine is added before or during the heating. 

 Generally speaking, the oxide is higher than Ni.,0„, some- 



