53 
on the Nature of certain Bodies. 
I hoped that an experiment of exposing the residuum to 
intense heat might enlighten the inquiry. I distilled one of 
the portions which had been covered with naphtha, in a tube 
of wrought platina made for the purpose. The tube had been 
exhausted and filled with hydrogene, and exhausted again, 
and was then connected with a pneumatic mercurial appara- 
tus. Heat was at first slowly applied till the naphtha had been 
driven over. It was then raised rapidly by an excellent forge. 
When the tube became cherry red, gas was develloped ; it 
continued to be generated for some minutes. When the tube 
had received the most intense heat that could be applied, the 
operation was stopped. The quantity of gas collected, making 
the proper corrections and reductions, would have been three 
cubical inches and a half at the mean temperature and pres- 
sure. Twelve measures of it were mixed with six of oxygene 
gas, the electrical spark was passed through the mixture ; a 
strong inflammation took place, the diminution was to three 
measures and a half, and the residuum contained oxygene. 
This experiment was repeated upon different quantities with 
the same comparative results. 
In examining the platina tube, which had a screw adapted 
to it at the lower extremity, by means of which it could be 
opened. The lower part was found to contain potash, which 
had all the properties of the pure alkali, and in the upper 
part there was a quantity of potassium. Water poured into 
the tube, produced a violent heat and inflammation ; but no 
smell of ammonia. 
This result was so unexpected and so extraordinary, that 
I at first supposed there was some source of error. I had 
calculated upon procuring nitrogene as the only aeriform 
