434 Hormell — Dielectric Constant of Paraffins. 



importance in securing the best possible results from the oscil- 

 lator. A rapidly rotating disc presenting projections to the 

 opposite terminal of the gap gave very indifferent results. 

 Zinc balls, polished brass balls, and brass balls with platinum 

 terminals inserted after the fashion of the iridium cylinders, 

 were used, but none of these gave the constancy secured 

 through the use of the iridium. Platinum terminals gave the 

 next best results, but on account of their rapid deterioration 

 they required almost constant attention in order to keep their 

 surfaces well polished. The iridium gap needs no attention 

 except for occasional adjustment of length. 



The secondary terminals of the Tesla coil are joined to the 

 primary terminals E / E (figure 2) of the Blondlot oscillator. 

 The remaining portion of figure 1 is shown in detail in 

 figure 3. 



The Blondlot oscillator (figure 2) is the modified form used 

 by W. D. Coolidge.* Some additions, however, have been 

 made in order to bring the adjustments more completely under 



*Annalen der Physik, lxvii, p. 578, 1899. 



