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PROCEEDINGS OF THE AMERICAN ACADEMY. 



paraffin, while in mica there is almost no variation in the region of 

 charging intervals considered. And if we examine the original throws 

 observed, we find that for the very short charging times the throws 

 vary greatly in case of paraffin, while for the mica they are practically 

 constant. All the paraffin condensers show close agreement in their 

 behavior, and so do the two mica condensers. (See figures 5, 6, and 7.) 



Observations of March 12 and 13. 



The following tables (XXXIV-XXXVII1) give mean values of ballistic 

 throws observed and reductions. The condensers " Par. KA " and 

 " Par. KB " are built of the same paraffined paper as the others, but 

 the sheets were merely piled together without the use of the hot flat- 

 iron. Thus we have layers of air as well as the paper sheets as the 

 dielectrics. 



TABLE XXXIV. (Figure 7.); 

 " Par. KA " vs. Am. 



