284 Messrs. Aelen and Pepys on the 
5,72 ; this is as near as we had a right to expect from the dif- 
ficulty of collecting the precipitate. 
Sto?ie Coal. 
Upon the suggestion of our mutual friend Professor Davy, 
we next examined the results of the combustion of stone coal 
and plumbago ; thermometer 57 0 Fahrenheit, barometer 
*9> 6 5- 
The stone coal from Wales, employed by maltsters, is well 
known to contain little or no maltha or mineral pitch, and to 
burn without flame. 
A portion of this coal was placed under sand in a crucible, 
and exposed to a strong heat for one hour ; 4 grains of it thus 
prepared were put into the tray : our oxygene left a residuum 
of 5 parts in 100, and we began with 49,84 cubic inches as 
usual. The tray being placed in the platina tube was heated 
to redness for about 10 minutes. When the gas was first pas- 
sed, we thought we saw a flash in the glass tubes. On suffer- 
ing the whole to cool the quantity of gas still remained the 
same, and the tray being drawn out contained only ,5 of a grain 
unconsumed. From the gas thus charged with 3,5 grains of 
coal. 
Lime water absorbed 53 parts from 100. 
The tests for oxygene 39 
Residuum - 8 or an increase of 3. 
100 
60° 
57 
3 di IF. 
Correction for Temperature. 
0,103 
3 
49> 8 4 
,50 
0,309 add for temp. 
5°, 14 
