154 



hertz's researches on electrical waves. 



with ti length of 1.8 meters. The quantitative results of these experi- 

 ments are shown in Fig. 5, in which the abscissie of the curve are the 

 double lengths of the rectangles, and the ordinates represent the corre- 

 sponding maximum sparking distances. The sparking distances could 

 not be determined with great exactness, but the errors were not suffi- 

 cient to mask the general nature of th6 result. 



Fio. 5. 



Curve showing relation between length of side of rectangle (taken as abscissa) and 

 maximum sparking distance (taken as ordinate), the sides consisting of straight 

 wires of varying lengths, 



In a second series of experiments the sides a c and h d were formed of 

 loose coils of wire which were gradually pulled out, and the result is 

 shown in Fig. 6. It will be seen that the maximum sparking distance 

 was attained for a somewhat greater length of side, which is explained 

 by the fact that in the latter experiments the self-induction only was 

 increased by increase of length, while in the former series the capacity 

 was increased as well. Varying the resistance of the micrometer cir- 

 cuit by using copper and German silver wires of various diameters was 

 found to have no effect on the period of oscillation, and extremely little 

 on the sparking distance. 



Fig. (5. 



Curve showing relation between length of side of rectangle (taken as abscissa) 

 and maximum sparking distance (taken as ordinate), the sides consisting of spirals 

 gradually drawn out. 



