146 PEOCEEDINGS OP THE AMERICAN ACADEMY 



XIII. 



ON THE CHARGING OF CONDENSERS BY GALVANIC 



BATTERIES. ' 



By B. O. Peirce and R. W. Willson. 



Presented March 13, 1889. 



I. The Use of Water Cells. 



The different methods which are commonly used for comparing the 

 capacities of condensers often lead to widely different results. 



Several condensers may be apparently of the same capacity when 

 tested by one process, while each differs from all the others under a 

 second set of conditions. Every condenser has its own character- 

 istics, and these must be specially studied before it can be used in 

 accurate work. 



The present investigation grew out of the discordant results which 

 one of us obtained in attempting to compare condensers made in dif- 

 ferent ways. Our experiments have removed some of our own diffi- 

 culties, and we think that an account of our work may prove useful 

 to others. 



We shall begin by considering the behavior of different batteries 

 when they are suddenly called on to furnish definite quantities of elec- 

 tricity in definite short times, and in this first paper we shall give some 

 results which we have obtained in using water cells. 



These results are interesting, because the water battery possesses in 

 an exaggerated degree some properties which are common to all bat- 

 teries, and which may seriously affect* the quantity of electricity fur- 

 nished to a large condenser by a cell with which it is connected for a 

 short time only. 



The cells that we used were made of ordinary " 2^ ounce wide mouth 

 flint glass bottles," filled to the neck with faucet water, and containing 

 each a strip of zinc and a strip of copper placed vertical and nearly par- 

 allel to each other, at a distance apart of about two centimeters. The 



* Von Beetz, Wied. Ann., xxvi. p. 24, 1885. 



