622 Prof. A. Battelli and Mr. L. Magri on 



metallic circuit. The last column contains the value of the 

 period, as given by our measurements. 



At the beginning of each table the values Lt of the self- 

 induction of the circuit are indicated — including the con- 

 ductors serving for the connexions — as measured by Nernst's 

 high-frequency current method ; the value R't of the re- 

 sistance by the metallic calorimeter, as calculated by 

 Hayleigh's formula, multiplied by the value of the ratio 



~ of the resistance of unit length of the wire of the spiral to 



that of an equal length of wire stretched out in a straight line 

 (§ 24, Part I.). The value of the capacity C of the condenser 

 and the theoretical value T of the period, calculated by the 

 formula 



T = — v/LC, 



v 



are also given. 



The quantities Q l5 Q 2 , and ~, likewise given in the tables, 



will serve for the study of the distribution of energy, to be 

 made in Section V. 



The theoretical values of T are, on the other hand, not 

 very sure, owing to the uncertainty attending the value of L 

 corresponding to the spirals, and we are thus not able to 

 ascribe to them more than a relative importance. 



32. The results contained in Tables VIII. to XI. are, 

 however, of a much higher importance. They are relative to 

 experiments made with circuits where the self-induction for 

 each period, which period, as derived from the measurements 

 made on the spark-photographs, could be calculated exactly 

 (see §§22 and 28, Part I.), and we wish to call attention 

 more especially to these. 



On the Plate (PI. XV.) some of the photographs which 

 served to determine T are reproduced. 



Xos. 1, 2, and 4 are reproductions of photographs relative 

 to Tables X., IX. e, and XL a, respectively. No. 3 is 

 relative to Table IX. 5 : this was obtained by producing 

 a discharge between platinum-iridium electrodes, all the 

 remaining being obtained with cadmium electrodes. 



