14^ 



Cray powder. 



Re«:iilts com- 

 fired. 



Affinity of 

 potassium for 

 copper. 



and ammonia 

 for its oxide. 



Ecpetimeat 

 in a tube of 

 platina. 



Tha solder 

 ieitioyed. 



A!«Ai.Vsis oir AMAfoNiA, 



In the upper part of the stbpicock there was fobnd sk 

 minute quantity of gray pbwder, which gaVe ammonia by 

 the operation of moisture. 



In tlo itrase, in which I haVe used the copper tube in like 

 processes of slow distillation, has there been less than 4 

 grains of potassium revived ; and thie proportion of nitrogen 

 to tlie hidrogeu in the gas evolved has been uniformly 

 much greater than in processes of rapid distillation in the 

 tubes of iron; but the whole quantity of elastic matter pro- 

 cured con>*iderably less. 



Copper has a much stronger affinity for potassium* thari 

 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 

 diminution bf its action upon the nitrogen in the nascent 

 state. Ammonia 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 

 hidrogen partly depends 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 rine gold solder. 

 The fusible substance was obtained (as usual from six 

 grains of potassium) in a tray of platina, where it was 

 brought into contact with a large surface of platina wire; 

 the distillation was slowly conducted; but before the tem- 

 perature 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 hidrogen 

 that filled the tube^ nearly f were nitrogen* 



* Copper heated in pota'ssiura speedily dissolves, and diminishes its 

 fusibility; but potassium requires a white heat to enable it to combine 

 ■trhh iroti. In another experimentj iti which I distilled the fusible sub- 

 stance in an iron trayj contained in the copper tube, a considerable quan* 

 titv of copper, that had been dissolved, was found in the state of [yovf 

 Tier deposited ^f on the tray, or loose ia the btttotn of the lube, 



I ata 



