th various Objects* 03 



Second, The facility with which metallic substances 

 are revived, in cases in which hydrogen is present. I 

 placed two platina wires, positively and negatively electri- 

 fied from 500 double plates of six inches, in fused litharge ; 

 there wa3 an effervescence at the positive side, and a black 

 matter separated at the negative side, but no lead was pro- 

 duced ; though when litharge moistened with water was 

 employed, or a solution of lead, the metal rapidly formed : 

 the difference of conducting power may be supposed to 

 produce some difference of effect, yet the experiment is 

 favourable to the idea, that the presence of hydrogen is 

 essential to the production of the metal. 



Third, Oxygen and hydrogen are bodies that in all cases 

 seem to neutralize each other, and therefore in the products 

 of combustion it might be expected that the natural ener- 

 gies of the bases would be most distinctly displayed, which 

 is the case; and in oxymuriatic acid, the acid energy seems 

 to be blunted by oxygen, and is restored by the addition of 

 hydrogen. 



In the action of potassium and sodium upon ammonia, 

 though the quantity of hydrogen evolved in my experi- 

 ment* is not exactly the same as that produced by their 

 action upon water; yet it is probable that this is caused by 

 the imperfection of the process*; and supposing potassium 

 and sodium to produce the same quantity of hydrogen from 

 ammonia and water, the circumstance, at first view, may be 

 conceived favourable to the notion that they contain hy- 

 drogen, which under common circumstances of combina- 

 tion will be repellent to matter of the same kind : but 

 this is a superficial consideration of the subject, and the 

 conclusion cannot be admitted ; for on the idea that in 

 compounds containing gaseous matter, and perhaps com- 

 pounds in general, the elements are combined in uniform 

 proportions; then whenever bodies known to contain hy- 

 drogen are decomposed by a metal, the quantities of 

 hydrogen ought to be the same, or multiples of each other. 

 Thus, in the decomposition of ammonia by potassium and 

 sodium, two of hydrogen and one of nitrogen remain in 



* There seems to be always the same proportion between the quantity of 

 ammonia which disappears., and the quantity of hydrogen evolved ; i. e. 

 whenever the metals of the alkalies act upon ammonia, supposing this body 

 to be composed of thrcs hydrogen, and one of nitrogen, in volume, two of 

 hydrogen and one of nitrogen remain in combination, and one of hydrogen 

 u set free. And it may be adduced as a strong argument in favour of the 

 theory of definite proportions, that the quantity of the metals of the alkalies 

 and nitrogen, in the fusible' results, are in the same proportions as those In 

 which they eaUt in the alkaline nitrates. 



combination. 



