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



Stefan, and Barton, the value of the resistance and the self- 

 induction — has been taken into account only in the case of 

 discharges along rectilinear wires, the true resistance and the 

 true self-induction for rapidly oscillating currents having 

 been calculated in this special case only. 



Finally, to treat this argument in a complete manner there 

 would be required the knowledge of the energy spent in the 

 different parts of the circuit, including the spark ; and, as a 

 matter of fact, a study of this distribution has formed the 

 object of important researches, such as those of Riess, Paalzow, 

 Villari, and more recently of Heydweiiler and of Oardani ; 

 but in all the experiments above mentioned, though the 

 relation between the measured quantities and the capacity, 

 self-induction, and resistance of the circuit is allowed for, yet 

 it is not ascertained how the distribution of energy may be in- 

 fluenced by the period of discharge. In the case of oscillating 

 discharges, in fact, measurements have been made either for 

 a single value of the period of oscillation only, or those made 

 for different periods, by different experimenters, are difficult 

 to compare with each other. A general and systematic study 

 of such elements as may have a bearing on the oscillatory 

 discharge phenomenon is therefore wanting. This we intended 

 to undertake. 



2. In this paper we give an account of the first part of 

 our researches, the results arrived at being already worthy 

 of notice. For these experiments we connected in the same 

 apparatus : 



(1) A device for measuring the period of oscillation ; 



(2) Condensers free from the defect of delay of polarization, 

 and circuits with exactly known coefficients of self-induction; 



(3) Special calorimeters to determine the amount of heat 

 evolved by the discharges, either in the spark or in the 

 metallic circuit traversed by them; 



(4) An electrometer enabling the potential of discharge to 

 be exactly measured; 



(5) A device for determining the residual discharge ; 



i. £., such apparatus as might enable us to know the period 

 of oscillation, energy disposable at the beginning of the dis- 

 charge, quantity of electricity effectively discharged, and the 

 energy dissipated in the form of heat in the different parts of 

 the circuit. 



I. Measurement of Pebiod of Oscillation. 

 A. Anterior Researches, 



3. Since Feddersen's beautiful experiments, calling the 

 attention of physicists to the phenomenon of condenser 



