HEAT PHENOMENA. 



243 



in the same sense. If so, a portion of tlie drainage of the Sierra must reach 

 great depths beneath the Washoe District, depths at which the tempera- 

 ture must be very high. It seems probable enough that meeting the fissure 

 of the CoMSTOCK and the partings subsidiary to it, the water thus conveyed 

 to the region of heat rises to the mines. The hypothetical structure sug- 

 gested is illustrated in Fig. 12. 



Fig. 12.— Ideal section across tlie Virginia Range. 



What it would account for.— lu a couutry SO ciisturbed by volcanic action and 

 so highly metamorphic as that underlying the Washoe District probably 

 is, the circulation must be much obstructed. Comparatively open water 

 channels leading from the Sierra are likely to connect only with fissures 

 almost capillary near the Lode, and vice versa. This would account for the 

 fact that some springs in the mines yield a steady supply of water, while in 

 other cases a great body is eventually pumped out and leaves only an insig- 

 nificant flow. It would also account for the increase of the heat of the 

 water with the depth, and its decrease at considerable distances from the 

 Lode and its accompanying fissures; for if narrow water channels extend 

 from a distant source of heat towards a constantly radiating surface, equality 

 of temperature can never result. The rising currents must constantly lose 

 heat. Descending currents will also be established, which will, however, 

 cause only local irregularities in the increment of temperature. Where 

 great quantities of water are drained from a single source, the tendency 

 would plainly be to a rise of temperature, and the head which the floods so 

 often show would find an ample explanation in the supposed connection 

 with channels from the great range. No reasoning on such points, however, 

 can be conclusive, for the opportunities of establishing the truth of the 

 hypothesis are very meager. 



