782 
MR. BRODIE ON THE CONDITION OF CERTAIN ELEMENTS 
Experiments below 1 00°. 
A. 
B. 
C. 
D. 
1. 
2. 
4-18 
2-35 
2-53 
T. 38° to 42°. 
7:4 
2-38 
3:1 
3. 
4. 
2-51 
2*81 
T. 24° to 26°. 
5:3 
3 : 2 
00 o 
5:2 
3 : 1 
5. 
6. 
4-32 
CO o 
o 
T. 16°. 
3:2 
2-88 
About 1 : 1 in the 
7. 
8 . 
*2-96 
2-77 
T. 0° upwards. 
3:2 
four experiments. 
9. 
10 . 
4-47 
3-25 
3-30 
4: 3 
3-35 
AgO not weighed. 
11. 
12 . 
6-10 
4-21 
3-93 
3:2 
4-06 
PbOj not weighed. 
The experiments in this Table, arranged in the order of ratios, as those at the 
higher temperature, give the following series : — 
3^ : 2, one experiment. 
5 : 3, two experiments. 
3 : 2, seven experiments. 
4 : 3, two experiments. 
These experiments placed beyond doubt, that, under similar circumstances of tem- 
perature and mass, the loss of oxygen from the metallic oxide stood in a certain fixed 
relation to the quantity of the peroxide of barium employed. They showed also 
(speaking generally) that this loss varied inversely with the temperature, but yet it 
appeared that within certain limits (II. experiments 5, 6, 7 , 8) the temperature might 
be very considerably altered without affecting the action. This was also the case, to 
a certain extent at any rate, with the mass ; for a perfect agreement was found be- 
tween experiments where the quantity of oxide of silver taken was considerably varied 
or even accidental. At the same time it was to be observed, that in determining 
these ratios a great deal would depend on the limits allowed for the error of analysis ; 
and it was a question of great importance, and yet by no means easy to decide, whether 
they were absolutely such as I have here assumed them to be ; that is to say, whe- 
ther the difference between two nearly identical experiments was to be attributed 
to the error of analysis or to a real, though small, difference in the action. I deter- 
mined therefore to make a more extended series of experiments, in which I might ob- 
* The water in these two experiments was cooled down in ice before it was poured on the substances ; at 
this low temperature no gas was given off. The action was allowed gradually to proceed as the temperature 
rose in the air. 
