590 



SCIENCE 



[N. S. Vol. XLIX. No. 1277 



the level of the valley. Fifteen miles to the 

 eastward a similar disintegration of a m-Oim- 

 tain in the peninsular axis was taking place 

 but without the accompanying gaseous emana- 

 tions. It is reasonable to assume that this 

 axial disturbance is attributable to slow up- 

 thrust due to volcanic pressure from the 

 underlying magma. 



It is somewhat difficult to reconcile the idea 

 of a cooling-ofF mass of material such as lies 

 on the slope of Mount Lassen as the origin of 

 the activity in the Valley of Ten Thousand 

 Smokes. The activity is too pronoimced, too 

 constant and too evidently magmatic to admit 

 of any explanation other than the direct vol- 

 canic origin of the gases. This valley is just 

 as truly volcanic to-day as are the craters of 

 Vesuvius and Kileaua. The superficial liquid 

 lava alone is absent. 



The character of the gaseous emanations 

 IKjints to their magmatic origin. I found that 

 the gases as they issued were not in chemical 

 equilibrium but continued to react after being 

 collected, the total volume increasing. More- 

 over, these gases far from being spent prod- 

 ucts of volcanic action contain some of the 

 most chemically active gases found issuing 

 from any volcano on the face of the globe. 

 The secondary products of these gases, that is 

 the sublimates, etc., formed by their action oh 

 the rocks through which they pass to the 

 sm-face are of a kind and quantity found 

 only in the most active volcanic areas. Dikes 

 of volcanic sublimates and incrustations sev- 

 eral feet high and himdreds of yards in 

 length mark the outlet of these subterranean 

 emanations. 



There are huge tunnels running horizontally 

 beneath the surface of the mud flow, tunnels 

 formed by the solvent action of the issuing 

 gases. At the upper end of the valley seventy- 

 five feet below the surface is a horizontal 

 tunnel large enough to drive a team and 

 wagon through. There are no incrustations 

 on the walls of this passage but they are 

 baked a brilliant brick red. It is only near 

 the surface that the cooling ofE of the gases 

 permitted the deposition of inerustants on the 



walls of the vents, and even here the tem- 

 perature is at times so high — several hundred 

 degrees centigrade — that little matter is de- 

 posited and the gases only become visible 

 several feet above the opening of the vent. 



Gautier^ shows that a cubic mile of granite 

 if forced to give up its aqueous content, as by 

 fusion, would release 100,000,000 tons of water. 

 Another 20,000,000 tons would be supplied if 

 the hydrogen contained in this mass of rock 

 could be burned. Water at a high tempera- 

 ture and under pressure reacts actively with 

 other compounds that are not appreciably 

 affected by it at ordinary temperatures. 

 Barus^ found that at 210°, 50 grams of water 

 dissolved over 200 grams of glass. With car- 

 bon dioxide it forms carbon monodixe, hydro- 

 gen, methane and free carbon. It decomjwses 

 metallic sulphides and no doubt reacts upon 

 other compounds of the metals. Should it be 

 dissociated into its elements as is quite pos- 

 sible at the temperature obtaining within vol- 

 canoes then it becomes at one and the same 

 time an oxidizing and reducing agent of the 

 strongest character. 



A better explanatory postulate for the phe- 

 nomena of the Valley of Ten Thousand 

 Smokes is afforded by considering the origin 

 of the gaseous emanations to be that of the 

 chemical reaction between the water content 

 of the crust in contact with the heated magma, 

 and the secondary reactions consequent upon 

 the chemical activity of the water imder these 

 conditions, gives rise to the variety of gases 

 and sublimates found issuing from the surface 

 vents. The explosion of June, 1912, may have 

 ruptured the sedimentary rocks underlying 

 the valley and permitted these gases to escape 

 through the crevices so formed or a subsidence 

 of the valley floor may have precipitated a 

 mass of the crust into contact with a region 

 sufficiently hot to fuse the rocks. The pres- 

 sure of the gases so formed may have caused 

 the explosion wrecking Katmai and the floor 

 of the valley itself. There is little doubt but 

 that the activity is far from subsiding for 



1 Compt. Bend., Vol. 143, 1906. 



2 Am. Jour. Sci., Vol. 9, 1900. 



