458 Mr. Davy's new analytical Researches 
iron. It occurred to me as probable, that this attraction, by 
preventing the potassium from rising in vapour at its usual 
temperature, and likewise by the general tendency of such 
combination to give greater density, might occasion a diminu- 
tion of its action upon the nitrogene in the nascent state. Am- 
monia has a strong attraction for the oxide of copper, and it 
consequently is not unlikely that the fusible substance may 
combine with metallic copper, and that this compound may not 
be entirely destroyed in the distillation. And assuming this, 
it may be conceived that the loss of hydrogene partly de- 
pends upon some combination of the basis of ammonia with 
copper. 
I had a tube, of the capacity of 2^ cubical inches, made of 
wrought platina, cemented by means of fine gold solder. The 
fusible substance was obtained (as usual from six grains of 
potassium ) in a tray of platina, where it was brought in con- 
tact with a large surface of platina wire ; the distillation was 
slowly conducted ; but before the temperature of the tube had 
approached to that of ignition, it dissolved and gave way at 
the points where it was soldered, and a violent combustion 
took place. Only 7 cubical inches of gas were collected ; but 
of this, allowing for the hydrogene that filled the tube, nearly 
| were nitrogene. 
I am making preparations for performing the experiment 
in a bored tube made from a single piece of platina, and like- 
wise in tubes made of other metals, and I hope to be able, in 
a short time, to have the honour of laying the results before 
the Society. 
I shall make no apology for bringing forward the investi- 
gation in its present imperfect state, except by stating that my 
