vn the Nature of certain Bodies, 483 



always found it to exist, even in cases wnere the ammonia 

 has been in great excess, and every part of the metal appa- 

 rently converted into the olive-coloured substance. 



No other account of the experiments of MM. Gay Lus- 

 sac and Thenard has, I believe, as yet been received m this 

 country, except that in the Moniteur already referred to 3 

 and in this no mention is made of the properties of the sub- 

 stance produced by the action of ammonia on potassium. 

 Having examined them minutely and found them curious, 

 I shall generally describe them. 



1. It is crystallized, and presents irregular facets, which 

 are extremely dark, and in colour and lustre not unlike the 

 protoxide of iron ; it is opaque when examined in large 

 masses, but is semi-transparent in thin films, and appears 

 of a bright brown colour by transmitted light. 



2. It is fusible at a heat a little above that of boiling water, 

 and if heated much higher, emits globules of gas. 



3. It appears to be considerably heavier than water, for it 

 sinks rapidly in oil of sassafras. 



4. It is a non-conductor of electricity. 



5. When it is melted in oxygen gas, it burns with great 

 vividness, emitting bright sparks. Oxygen is absorbed, ni- 

 trogen is emitted, and potash, which from its great fusibility 

 seems to contain water, is formed. 



6. When brought in contact with water, it acts upon it 

 with much energy, produces heat, and often inflammation, 

 and evolves ammonia. When thrown upon water, it dis- 

 appears with a hissing noise, and globules from it often 

 move in a state of ignition upon the surface of the water. 

 It rapidly effervesces and deliquesces in air, but can be pre- 

 served under naphtha, in which, however, it softens slowly, 

 and seems partially to dissolve. When it is plunged under 

 water filling an inverted jar, by means of a proper tube, it 

 disappears instantly with effervescence, and the non-ab- 

 sorbable elastic fluid liberated is found to be hydrogen gas. 



By far the greatest part of the ponderable matter of the 

 ammonia, that disappears in the experiment of its action 

 upon potassiumyeTifjently exists in the dark fusible product. 

 On weighing a tray containing six grains of potassium, be- 

 ll h 2 fore 



