48-i C. Barus — Note on Volcanic Activity. 



glass in water will not be amenable to these simplified con- 

 ditions at once, but there can be no doubt that the general 

 bearing of the effect of temperature on 1) is definitely fore- 

 shadowed by Nernst's equation, even if the case above is rather 

 one of the solution of water in glass. If it were known that 

 this liquid is more soluble in hot glass than in colder glass, 

 under the requisite temperatures, similar conclusions as to the 

 diffusion of cold to hot might be drawn ; but all that has been 

 proved by experiments is the occurrence of a larger rate of 

 solution for the hot glass. 



Apart from theoretical considerations, however, the question 

 as to the distribution of a solvent in a solution, the parts of 

 which are kept at different temperatures, is one of considerable 

 interest. It is well worthy of extended experimental investiga- 

 tion, particularly in those cases in which a high degree of 

 concentration obtains. On this subject I hope to offer some 

 contributions myself, at another opportunity. 



3. To return to the subject of vulcanism ; as I take it, the 

 diffusion of water takes place from colder to hotter strata under 

 the relatively small pressure required to keep it liquid. Thus 

 it is conceivable in a favorable case, that the lower strata will 

 in the course of time be more fluid than the upper strata both 

 from heat and from solution, so that heat may pass from lower 

 to higher levels by convection. In such regions, in other words, 

 convection would bring an excessively high temperature 

 abnormally near the surface ; or there would be an abnormal 

 local rise of the isotherms. Hence, recalling that the solution 

 of water in glass is accompanied by a remarkable contraction 

 of the system of glass and water, and is therefore in itself 

 favorable to the localized production of heat, while the identical 

 phenomenon (by reason of the diffusion of water from cold to 

 hot) is at the same time tending to raise the deeper and hotter 

 isothermal levels nearer to the earth's surface, one may reason- 

 ably conclude that two phenomena both conducive to volcanic 

 activity are acting in concert. Furthermore they are liable to 

 be evoked along the shore line of the ocean, and particularly 

 in those places where this line is unstable and undergoing 

 displacement. For it is here that water will most probably 

 have access accidentally to unusual depths. 



Brown University, Providence, R. I. 



