436 QUICKSILVER DEPOSITS OF THE PACIFIC SLOPE. 



penetrate to a cleptli of at least twenty or thirty feet, and this helps to ex- 

 plain the fact that the water reaching the surface carries so little quick- 

 silver. These same causes, or some of them, must also induce precipitation 

 of the other ores and of g'old from solutions. 



Another method by which mercuric sulphide may be precipitated is, as 

 has been seen, mere dilution. Now, ascending solutions of cpiicksilver must 

 sometimes meet with springs, and, when they do so, metacinnabarite or 

 black sulphide will be precipitated, and n-ith it also a small amount of me- 

 tallic quicksilver. In nearly all mines a small quantity of virgin quick- 

 silver is found, and in most it constitutes a very small proportion of the 

 entire ore.^ Accompanying this precipitation is the formation of sodic hypo- 

 sulphite, which actually occurs in the waters of Steamboat Springs. Dilu- 

 tion of solutions of quicksilver with extraneous spring waters tluis alTords 

 one method of explaining the occurrence of metacinnabarite" found in at 

 least five of the mines of California, and also that of native quicksilver. 

 Native quicksilver, however, occurs in many mines in which no metacin- 

 nabarite has ever been seen. This does not preclude the supposition that 

 the metal has been isolated by dilution, for black sulphide in the presence of 

 solutions of mercury might readily be converted into the allotropic modi- 

 fication, and I know of no reason for denying that much of the cinnabar of 

 the ore deposits may have been deposited in the amorphous state. Cinna- 

 bar and metacinnabarite are sometimes found mixed, as if a conversion to 

 the red mineral were incomplete. In one of the abandoned drifts near the 

 exhausted ore bodies of the New Idria mine the walls were covered with 

 incrustations of secondary salts over an inch in thickness. In this mass, 

 which had been deposited since the drift was opened, I found a tiny vein of 

 cinnabar, about three inches in length and perhaps a quarter of a milli- 

 meter in thickness. The existence of this very recently formed veinlet evi- 

 dently indicates the presence in the mine of solvents of mercuric sidphide 

 in tritling quantities, w.hich might be quite sufficient, however, to convert 

 black ore into cinnabar. Professor Sandberger has described a series of 



' It is a very curious fact that from ancient times to the beginning of the last century virgin quick- 

 silver was snppose'l to possess qualities superior to that of the metal reduced from cinualiar (Briiok- 

 mann, Magualia Dei iu Lncis Subterraneis). 



-The forniatiou of metacinnabarite by dilution has already been suggested by Mr. .S. B. Christy. 



