18 Prof. A. Battelli and Mr. L. Maeri 



on 



a manner perfectly similar to that described in the above 

 quoted article. The number n of complete oscillations was 

 about 126 per second. The very regular speed of the 

 tuning-forks — the duration of whose oscillations was obtained 

 by comparison with a Graham pendulum regulated by means 

 of a chronometer of the Royal Navy — facilitated the execu- 

 tion of these measurements, from which we derived the 

 following values : — 



Condensers I. and II. in parallel 0*015750 microf. 



Condenser No. 1 0*0079763 „ 



No, II 0-0078849 „ 



17. Resuming, we mav write in the following table the 

 values of the capacities as obtained by the various methods: — 



Electro- 



A. The two condensers in parallel, static Units. 



[c.g-.s.] Microf. 

 derived from comparison with 



Latimer-Clark standard ... 14388 0*015987 

 j derived from bridge measure- 

 ments 14175 0*01575 



B. Condenser No. 1 only. 



Capacity derived from bridge measure- 

 ments 7178 0*007976 



C. Condenser No. 2 only. 



Capacitv derived from bridge measure- 

 ments 7096 0*007885 



The sum of the capacities of condensers No. 1 and No. 2 

 thus agrees fairly well with that of these two condensers 

 when connected in parallel, the more so as measurements of 

 the capacity of each condenser apart will present less cer- 

 tainty on account of their small value, and as the neighbour- 

 hood of the other condenser will have a slight influence on 

 the capacity of either of them. 



The smallness of the difference between the absolute value 

 as found by us by the bridge method and the one derived 

 from a comparison with the Latimer-Clark standard may be 

 considered as an evidence of the accuracy of our measure- 

 ments. This difference is probably due to the fact that the 

 standard may have undergone a slight variation in the fifteen 

 years passed since Prof. Roiti made his experiments, and that 

 with the comparative experiments the charge lasted 1 sec, 



