AURUM, OR GOLD.
William Withering translation
§ 144.
The ſpecific gravity of this metal, when pure, is 19,640. Aqua regia diſſolves it; but except the dephlogiſticated muriatic acid, and in certain circumſtances the nitrous, no ſimple acid acts upon it, unleſs it has been previouſly calcined[56]. The quantity of phlogiſton neceſſarily taken away in the ſolution of 100 parts of gold, I eſtimate at about 394; whilſt the ſame quantity of ſilver, loſes by ſolution in the nitrous acid, 100[57]. Gold retains the phlogiſton neceſſary to its metallic form, more obſtinately than any other metal, except, perhaps, platina. It melts and calcines in the focus of a burning glaſs at 1301 degrees of heat.
§ 145.
AURUM nativum (gold native) united to ſilver.
Native.
73I do not know that gold has ever yet been found perfectly pure.
§ 146.
AURUM nativum (gold native) united to copper.
Native.
§ 147.
AURUM nativum (gold native) united to ſilver and copper.
Native.
§ 148.
AURUM nativum (gold native) united to ſilver, copper, and iron.
Native.
§ 149.
AURUM (gold), mineralized by ſulphur, by means of iron.
Pyritical.
Cronstedt Min; § 166. a. Pyrites aureus.
But ſome doubt may be made about the mineralization of gold[58].
74§ 150.
AURUM (gold) mineralized by ſulphur, together with ſilver, lead, and iron.
Minera aurifera Nagyayenſis.
I have not yet fully examined this[59].
75