On some Combinations of Platina. 3ffi 



or soJa, and black oxide of plalina remains ; but whethcT 

 the oxide in this instance is quite pure, I have not had aa 

 opportunity of determining. It is insokible in pure ammo- 

 nia; but, when boiled to dryness with this alkah, fuhnma- 

 ting plalina appears to be formed, a compound which I shall 

 presently notice. 



The ammonia sulphate of platina possesses in some 

 decree the peculiar properties of detonating compounds. 

 When a little of it is exposed to a moderate heat ori a 

 slip of plating, a hissing noise is produced, accompanied 

 with slight explosions, and the substance is partially 

 dissipated in dense fumes. Its solution in muriatic acid 

 affords a dense white precipitate with muriatt^ of barytes. I 

 have made no experiments on this compound, so as to de- 

 termine its composition with accuracy. Oneexpei^iment, 

 however, may afford an imperfect approximation of this knid. - 

 8 grains of ammonia sulphate of platina were dissolved m 

 muriatic acid ; the solution was boiled to dryness m a 

 platina crucible, and decompounded at a red heat. It fur- 

 nished 5 grains of metallic plalina. 



This would seem to indicate in 100 parts. 



Oxideof platina 70 



Sulphate of ammonia") 



and water j ^^ 



100 



11. Of fulminating Platina. 

 This compound is obtained, by introducing dry finely 

 pulverized sulphate of platina into pure ammonia, and suf- 

 fering them to remain together for several hours. It may 

 also be procured by pouring this alkali on the dry sulphate 

 exposed to the atmosphere,'' but the former method appears 

 to be the best. — After remaining in contact with the ammo- 

 nia, it is to be washed with distilled water, and dried at a 

 temperature 'not exceeding the boiling point of water. I 

 have not been able to examine this substance with much 

 attention. The few experiments I have made with it at 

 short intervals of leisure I shall state. 



Its colour is light brown. It is procured in small loosely 

 coherent lumps, or in powder. It is tasteless, and insolu- 

 ble ill water. It explodes at the temperature of 490 

 Fahrenheit, which was ascertained by introducing a ther- 

 mometer into mercury heated, so as to explode the powder. 

 When about half a grain in fine powder was gradually 

 healed in a platina crucible, it exploded at once with a 

 loud report. When a little of it in small lumps was heated 



