HEAT — VEINS. 385 



the siliceous deposits frequently contain pyrite and cinnabar (HgS) and 

 the sulphur bank, which has there been formed through the heated vapors, 

 has been worked as a mercury mine. J. D. Whitney described in 1865 a 

 specimen of gold in cinnabar which was supposed to have come from near 

 " Sulphur Springs," four miles ' south of Bear Valley, between Clear Lake 

 and Colusa; and Mr. M. Atwood removed doubt as to the source of the 

 specimen by finding in a fissure at the place mentioned (as reported by 

 Mr. Phillips) cinnabar overlaid by a brilliant deposit of metallic gold. 

 Similar facts are reported by Le Conte (1882, 1883), from the Clear Lake 

 region and Steamboat Springs. In the former, at "Sulphur Bank," occurs 

 sulphur with cinnabar below (which is now worked), and also pyrite and 

 gelatinous silica. 



Le Conte explains the occurrence of cinnabar (HgS) on the ground of its solubility in 

 a hot solution of sodium sulphide (NRjS), — this alkaline sulphide resulting from the action 

 of the sulphur gas on the rocks which contain a soda-lime feldspar, — and its subsequent 

 deposition. (For Le Conte on Vein-making, see Am. Jour. Sc, 1882, 1883.) Becker 

 sustains, by experiments (1887), the view that the metallic sulphides (HgS, FeSj, ZnS, 

 and less easily Cu^S) are soluble in solutions of alkaline sulphides, and that they pass 

 in vapors to be deposited in the veinlets and fissures of the rocks above. He observes 

 that the Steamboat Springs are now depositing gold ; that gold is dissolved by a hot solu- 

 tion of Na2S, and that 843 parts of a cold solution of Na2S will dissolve one part of gold. 

 Deposition of the sulphides is occasioned by cooling ; by contact with acid waters — these, 

 according to Le Conte, descending from the surface where some of the sulphur in the 

 gases makes sulphuric acid and aluminum sulphate ; and also by dilution. Becker pub- 

 lished in 1888 a full report on the quicksilver mines of California. The following facts 

 illustrate further mineral transformations. Daubree found, in the thermal waters at Bour- 

 bonne-les-Bains, in the bottom of a part of which, in Roman times, bronze, silver, and gold 

 coins had become buried, the following mineral species, derived from the alteration of the 

 metal of the first two of these kinds of coins through the agency of the mineral waters, their 

 temperature 140° P. : the copper ores, chalcocite (Ca,S), chalcopyrite (CuFeS.^), bornite 

 (CujFeSg), tetrahedrite, atacamite, cuprite (CU2O), chrysocolla, native copper; the lead 

 ores, cerussite (PbO.C02), anglesite (PbO.SOg), galena (PbS), phosgenite, and pyrite. 

 The bronze was found to consist of copper, tin, and lead, or of copper and zinc, with a 

 trace of iron. The waters afforded, on analysis, chlorides and sulphates of the alkalies 

 (Na2, Kj, Ca, Mg), with bromides and carbonates of Ca and Fe, an alkaline silicate, with 

 traces of arsenic, manganese, iodine, boron, lithium, strontium, caesium, rubidium, and, in 

 exhalations, some H2S, N, and O. Similar results were observed by Daubree at the warm 

 springs of Plombieres, Department of the Vosges. 



Veins made by heat in the Earth's Crust, without aid from deep-seated Igneous 



Ejections. 



The crustal heat may be that of the earth's crust either during, or not 

 during, an epoch of metamorphism. Under this head are included most of 

 the great and small granite veins of the world, the auriferous (gold-bearing) 

 quartz veins, and all the common veins of metamorphic rocks. They some- 

 times intersect the foliation, but very often follow it. Their formation was, 

 in general, part of the results of metamorphic heat and conditions ; and the 

 movements attending mountain-making, which produced the metamorphic 



