SOLFATAKiSM IN THE KEDINGTON. 287 



soifataric gases. — At oiie poi'iit Oil tlie 150-foot level, ill an old stope, the 

 temperature is high and pungent sulpliurous odors are very noticeable. At 

 this place aeicular sulphur crystals also form upon the timbers. 1 am una- 

 ble to explain this occurrence except upon tlie supposition that sulphurous 

 acid and hydrogen sulphide are escaping, and by their mutual decompo- 

 sition yield sulphur. It is not infrequently the case in mines tliat hydro- 

 gen sulphide is produced by the reducing action of timber upon soluble 

 sulphates, and the oxidation of this gas may then yield sulphur; but I do 

 not know of any reaction by which sulphurous acid can be evolved at mod- 

 erate temperatures from soluble sulphates in contact with organic matter. 

 The presence of sulphites or hyposulphites among the mine deposits might 

 lead to the evolution of sulphurous anh3'dride; but, while such salts appear 

 to form near the surface at Steamboat Springs and Sulphur Bank, T have met 

 with no evidence, there or elsewhere, of their deposition at depths such as 

 to preclude the oxidizing action of the atmosphere upon alkaline sulphides. 

 Hence it seems possible to account for the sulphurous anhydride which 

 reaches the 150-foot level of the Redington onl}' on the supposition that it 

 represents a feeble remnant of soifataric action. The only other instance 

 known to me in which sulphur is similarly crystallized on timber is at some 

 of the workings of the Sulphur Bank which are now abandoned. In that 

 case there is no question that the sulphur is produced by the mutual decom- 

 position of sulphurous acid and hydrogen sulphide of soifataric origin. 

 The high temperature of the spot where the sulphur crystals were found 

 at Knoxville also strongly suggests volcanism. I have no record of this 

 temperature, but I am certain that it considerably exceeded lOC^F. No 

 work was progressing near the spot, so that the abnormal temperature was 

 not ascribable to candles and bad ventilation. The evolution of heat was 

 tolerably rapid, for the locality was not closed off from the otlier workings. 

 The high temperature must have been due either to volcanic emanations or 

 to local chemical action. The heat of the Comstock mines has been hypo- 

 thetically ascribed to local chemical action, but the hypothesis is not borne 

 out for those mines either by observation or by experiment, and I know of 

 no case in which such a temperature as that in the Redington, under similar 

 conditions of ventilation, has been clearly traced to local decomposition of 



