Part 17

§ 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.

§ 150.

AURUM (gold) mineralized by ſulphur, together with ſilver, lead, and iron.

Minera aurifera Nagyayenſis.

I have not yet fully examined this.

PLATINUM, OR PLATINA.

§ 151.

Its ſpecific gravity is 18,000, when very pure. It diſſolves in aqua regia, and the loſs of phlogiſton during the ſolution, according to the experiments hitherto made may be expreſſed by 756. Beſides the muriatic acid, which when dephlogiſticated diſſolves every metal, no acid acts upon platina without it has undergone a previous calcination. It ſeems to retain its phlogiſton more obſtinately than any other metal. To melt it requires a heat greater than that at which iron melts.

§ 152.

PLATINA native united to iron. Native.

CRONSTEDT Min. § 179.

I believe it has never been found quite free from iron, but this can be ſeparated by art.

ARGENTUM, OR SILVER.

§ 153.

Its ſpecific gravity is 10,552. The nitrous acid readily diſſolves it, the vitriolic muſt be boiling hot; the muriatic attracts its calx very ſtrongly, but cannot remove its phlogiſton and therefore cannot diſſolve it in its metallic ſtate. The quantity of this phlogiſton which cauſes the difference betwixt its metallic and its calciform ſtate I before expreſſed as 100 in 100 parts of ſilver. But the force with which it retains this portion of its phlogiſton is leſs than that of gold; that is, it occupies the third place in a ſeries of all the metals. It melts at 1000 degrees of heat.

§ 154.

ARGENTUM nativum (ſilver native) united to gold. Native.

§ 155.

ARGENTUM nativum (ſilver native), united to copper. Native.

§ 156.

ARGENTUM nativum (ſilver native), united both to gold and copper. Native.