642 On Oscillator 11 Discharges. 



that of d, though adopting as maximum distance that between 

 our circuits and the earth, is always smaller than 2 metres, 

 the preceding formula will give 



7 <6 Xmf> 



or -l < 0-000066. 

 i 



In the case of circuits wound into spirals, the dispersion 

 cannot be much different ; hence with our experiments it 

 may always be regarded as lieglio-ible. 



That the sum of the energies spent outside the metallic 

 circuit is negligible within the limits of accuracy reached 

 with our measurements of the discharge-potential and of the 

 heat evolved in the spark, may also be derived from the 

 experiments themselves. In fact, in the Tables I. to VII. 

 we compared the sum Qi-r-Q? of the heat evolved in the 

 spark and in the metallic spiral, with the energy corresponding 

 to JCY 2 ; and from a perusal of those tables it may be 

 seen that nearly all the energy is found again in the form of 

 heat in those two portions of the circuit. On the other hand, 

 we wish to maintain that the uncertainty as to the true value of 

 V (due to the great variability of the effective length of the 

 spark), and the fact that the spark-calorimeter does not give 

 a very exact measure of all the heat evolved in the spark 

 itself, deprives our comparison of part of its value. In these 

 first researches, however, it was more interesting to study the 

 repartition of the energy between the spark and a metallic 

 part of known resistance, than the absolute value of the total 

 energy; and this repartition we have succeeded in ascertaining 

 with sufficient accuracy. 



Conclusions. 



4'3. From a survey of these results the following conclusions 

 may, in our opinion, be drawn : — 



1. The period of oscillation agrees, within the limits of 

 experimental errors, with the theoretical value, as given by 

 Thomson's formula. The less satisfactory accordance observed 

 in the case of very short periods (about 7 x 10~ 7 ) is due to 

 the fact that in such cases the self-induction of the circuit 

 cannot be allowed for. 



2. The resistance of the spark in the case of little-damped 

 discharges, due to rather large amounts of electricity, as 

 those given by our condensers, and for explosive distances 

 comprised between 1 and 5 mm., is very small and always 

 inferior to 1 ohm. Ceteris paribus, this resistance increases 

 considerably less rapidly than the length of the spark. This 



