HI-STOIlY OF GOLD. 243 



fuilitates against our being able by these means to ascertain 

 the degree of oxidation of this precious metal. 



If muriatic acid be applied io -tiiis powder, it dissolves the Action of 

 oxide, and leaves the pure gold, which is always more abun- ^'^ ** "^'^ 

 dant. Nitricacid of 40° dissolves only a few atoms of the 

 oxide, and it must be assisted by heat. This solution is of a 

 slight yellow colour; and if it be diluted with water, the gold 

 separates from it of- the colour of fulminating gold. This pre- 

 cipitate still retains the state of an oxide, accordingly the mu- 

 riatic acid dissolves it immediately. 



The aqueous sulphuric acid dissolves some of it also, but 

 less than the preceding. It is seen by the violet colour it 

 assumes, if a few drops of muriate of tin be added. To con- Carbonates not 

 elude, carbonates are not in any respect more advantageous ^j^^^g^ ^ *^ 

 for the 'precipitation of gold ; which has compelled me to give 

 up this point, repeating the words of Bergman : " all gold is Gold, diftcult 

 " precipitated with difficulty, so that lam uncertain of the *° ^^"^"i''^'"^''* 

 *' weights." 



Fulminat'mg Gold. 



A hundred parts of fulminating gold passed through sulphu- Fulminating 

 rated hydrogen, washed and heated, left seventy-three of pure ^*^ 

 gold.^ A hundred parts of gold consequently give about 137 

 of fulminating gold. If any means of appreciating the ammo- 

 nia that attaches to the oxide could be found, the oxidation 

 of the gold could easily be deduced from this. 



Kunckel observed, that the oxide of gold obtained by means 

 of alkalis, and moistened with ammonia, became fulminating. 

 Orschal too must be reckoned among the number of thot^e 

 who have been near falling victims to its detonation. An agate Dangers at- 

 mortar, in which he was rubbing this dangerous oxide, flew '^ * 



into splinters under his hand. He received no wound, but he 

 adds that he felt a sensation, as if a musket loaded with sand had 

 been discharged full in his face. According to him, Raymond 

 I-ully experienced a similar accident. 



Orschal too used fulminating gold to give a purple colour to Uscd to colour 

 glass. It even appears, that this use of it was known before his S^**^^ purfilu. 

 time. Hence it might have been concluded at that period, 

 that tin was not a necessary ingredient in the purple colour. 



I i 2 Fulmiiia- 



