EXPEEIMENTS ON KAOLINIZATION. 



307 



Table XIII. 



a= +0.033; 



P= +0.000106 + 0.000006. 



The constants /? in these tables are, however, of inconvenient magni- 

 tude, and it will be more expedient to represent these quantities on the 

 scale of a year. Let JT, then, denote the apparent increase of the tem- 

 perature of the rock in the apparatus per year, the variation being sup- 

 posed to have continued during the whole of this time in the same manner 

 as during the time of observation. Then from Tables XI. and XII., which, 

 together, comprehend an interval of two weeks, 



JT — + \°J)^0°.\- 



and from Table XIIL, corresponding to the same interval, 



z/T = -0°.9dbO°.l. 



These figures express the final result of the investigation. They indi- 

 cate that, as far as these experiments go, it would be about equally correct 

 to assume a positive or a negative thermal effect from the action of aqueous 

 vapor on the rock; and that for the present, at least, a thermal effect may 

 be assumed to be absent. 



By comparing corresponding- values of a in the tables above, it becomes 

 evident that the changes in the values of ^t cannot in any way be referred 

 to the thermo-element; nor is there, in the results taken as a whole, an effect 



