816 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



of the electrode with one of the laminae of the crystal might aid the 

 charge in one direction of charge and hinder it with the opposite di- 

 rection of charge, and might, hence, cause differences in the capacity 

 coefficients in the two directions, and might also account for the form 

 of the curves of Figure 12. We have submitted the thermoelectric 

 hypothesis to a mathematical treatment, assuming that both Joulean 



TABLE VII. 

 Data of Experiment II. Compared with Equation (30). 



heat and Peltier heat act at the junction of one of the electrodes with 

 the crystal, and have arrived at the result 



(1) That the assumption of Joulean heat alone in combination with 

 capacity gives a capacity coefficient that is the same in the two opposite 

 directions, and for both directions the effect of the heat term is to make 

 the capacity coefficient diminish with increasing applied e. m. f. 



(2) Peltier heat and Joulean heat, if both present in combination 

 with the capacity, would give different capacity coefficients in the two 

 opposite directions, but the effect of the heat would still manifest itself 

 as an apparent decrease of capacity with increase of applied e. m. f. for 

 both directions of application of the e. m.f. 



Neither of these results is in complete accord with the experimental 

 facts. 



Various other possible explanations of the apparent unilateral ca- 

 pacity of the crystal condenser have suggested themselves, but we have 



