300 



GEOLOGY or THE COMSTOCK LODE. 



Table II. 



Table III. contains the successive values of Jt, or the difference of 



temperatui-e between the interior and exterior of the rock-chamber. It 



also shows the date of each observation and the number of hours which 



had elapsed since ebullition first set in. Corrections for the variation of a 



and the electromotive force of the normal element E have been applied. 



During the time covered by the first six observations the water lost by 



evaporation was supplied somewhat intermittently; subsequently, however, 



as well as throughout all succeeding experiments, it was fed into the boiler 



drop by drop, so that the feeding process may be considered as practicalh" 



continuous, ^t is positive, this sign having been chosen to indicate that 



the space exterior to the rock-chamber — or the end of the thermo-element 



in steam — is the hotter. 



Table IIL 



