45 $ Mr. Davy's new analytical Researches 
have generally found more potassium destroyed, and less ni~ 
trogene in proportion in the aeriform products. In such cases 
likewise, the loss of weight has been much greater ; the gases 
have been always clouded, and the adaptors, after being ex- 
posed to a moist air, emitted a smell of ammonia ; from which 
it seems likely that small quantities of the dark gray substance 
described in page 50 of this Volume, are sometimes carried 
over undecompounded in the operation. 
In some late experiments, I substituted for the iron tube, 
a tube of copper, which had been bored from a solid piece, 
and the sides of which were nearly a quarter of an inch 
in thickness. My object in using this tube was not only to 
prevent the heat from being too rapidly communicated to the 
fusible substance, but likewise to be secure that no metallic 
oxide was present, for though the iron tubes had been care- 
fully cleaned, yet still it was possible that some oxide, which 
could not be separated from the welded parts, might exist, 
which of course would occasion the disappearance of a certain 
quantity of potassium. 
I shall give the results of one of the processes, which I 
regard as most correct, made in the tube of copper. The 
barometer was at 30.5; thermometer was at 59 0 Fahrenheit. 
The tube contained two cubical inches and half, and was 
filled with hydrogene. 
6 grains of potassium, which had absorbed 13 cubical inches 
of ammonia in a copper tray were employed. 
The adaptors connected with the mercurial apparatus and 
the stop-cocks, contained .7 of atmospherical air. 
The gas given off was collected in two portions. 
The first portion was equal to 11 cubical inches. It con- 
