150 
Proceedings of the Royal Society 
A B and C were then dried at 100° C., and on titration yielded 
the following percentages of O : — 
A, 
5*95 per cent. 
B, 
. 5-25 „ 
C, .... 
. 4-93 „ 
The analysis of A gave the following 
results : — 
CdO .... 
= 85-8 
h 2 o 
= 6-9 
CO, ... . 
= 31 
0 
= 5-95 
101-75 
The properties of this substance resemble closely those of the zinc 
compound. It is more decidedly yellow in colour, however, and 
readily yields on ignition the ordinary brown oxide of cadmium, 
water and oxygen being given off. On heating a portion of A to 140° 
for several hours, it was partially decomposed, and became browner 
in colour. This substance, on titration, gave 7 -4 per cent, of 
oxygen, deducting carbonate of cadmium as represented by 3*1 per 
cent. C0 2 and the water the percentage of O = 7 -34, in the anhydrous 
oxide. 
For the preparation of the magnesium compound we used 
several solutions of sulphate of magnesium of different strengths, 
and adding varying quantities of the ammonia solution. The quality 
of the product varied in each case according to the mode of pre- 
paration. 
Magnesium A was precipitated from a solution containing chloride 
of ammonium and free ammonia, and was filtered, after stand- 
ing all night in contact with the liquid from which it was pre- 
cipitated. The precipitate, dried at 100° C., on titration, was found 
to yield only 0‘29 per cent, of O, showing that it was nearly all 
magnesia. The effect produced by varying the quantity of ammo- 
nia added, while all the other conditions were kept as nearly as 
posssible the same, is well shown in the following three oxygen 
§stimations : — 
Magnesium B contained 3-92 per cent. O. 
„ C „ 3-1 
