243 



Xntf. This mineral contains sulphide of copper and a trace of iron. 

 See Dana, Mineralogy, p. 5. It differs from tetrahedrite, or gray copper, in 

 not giving a red sublimate when heated. See, I.e., p. 103. 



71 k SPECIMENS ILLUSTRATING THE STAGES IN THE PROCESS OF SMELT- 

 ING ORE. 



a. Five specimens of roasted ore. 



b. Pure metal in small nodules. 



MERCURY. 



715. CINNABAR. (Sulphuret of Mercury.) 



a. Massive. 



THALLIUM. 



716. THALLIFEROUS IKON PYRITES. 



a. Massive. 



. This mineral is a sulphide of iron containing thallium and 



other metals. See Dana, Mineralogy, p. 63. 



GOLD. 



717. NATIVE. 



a. On quartz. 



TIN. 



718. CASSITERITE. (Tin Stone, Native Oxide of Tin.) 



a. Crystallized. 



b. Massive, water worn. (Stream Tin.) 



c. Pseudomorphic, after felspar. 



Note. Specimen c consist of three not quite perfect crystals. It 

 probably came from WhealGoates, near St. Agues, Cornwall. See Dana, 

 Mineralogy, p. 158. 



719. STANNITE. (Tin Pyrites, Bell Metal Ore. Sulphuret of Tin.) 



a. Massive. 



Note. This mineral usually consists of the sulphides of tin, copper, 

 iron, and zinc. See Dana, Mineralogy, p. 68. 



TITANIUM. 



720. RCTILB. (Red Schorl, Titanite, Native Oxide of Titanium.) 



a. Crystalline, of a reddish brown colour. 



Note. Untile consists almost entirely of titanic aci.l, with traces of 

 iron only. See Dana, Mineralogy, p. 160. 



721. NITRIDE OF TITANIUM. 



a. Crystallized, of a copper-red colour. 



Note. This is a fine specimen of the crystals, deposited oil a pkce of 

 the slag from an iron fut uace. 



