90 



Transactions of the Royal Canadian Institute 



Specimen 

 B 



d 

 ,689 



Cun'e 

 a-3 



Table II — Continued. 

 R R' Mean R' 

 46.60 46.50 



54 



46.40 



Mean for one insulator. 



2 in series 1.000 a-2 44 56.3 



2 in series 1.351 a-1 52 50.9 

 Mean for two insulators in series 

 Bin 1.351 a-1 41 59.2 

 series 58 . 6 



3 in 2.000 a-0 50 50.8 

 series 51.8 

 Mean for three insulators in series 



4 in 1.351 a-1 35 67.3 

 series 67 . 7 

 4in 2.000 a-0 41 59.3 

 series 58 . 4 

 Mean for four insulators in series 



58.9 



51.3 



67.5 



58.85 



4 . 37cm. 



Jeffrey- Dewitt Suspension Type Insulator 



Specimen d Curve R R' Mean R' R/R' \/x Capacity 



2-A 1.000 a-2 54 46.1 45.9 1.176 1.020 7.55cm. 



45.7 



2-B 1.000 a-2 55 45.7 45.6 1.206 1.050 7.77cm. 



45.5 



Mean for one insulator 7 . 66cm. 



Hewlett Suspension Type Insulators 



Specimen d Curve R R' Mean R' R/R' \/x Capacity 



3-A 2.000 a-0 68 32.8 32.8 2.072 .690 5.11cm. 



32.8 



3-B 2.000 a-0 69 32.4 32.4 2.128 .700 5.18cm. 



32.4 



Mean for one insulator 5 . 14cm. 



Comparison between Tables I. and II. shows that the second method 

 gives much the more satisfactory results. It is applicable to the measure- 

 ment of other small capacities, such as that of electrometers. 



It must be remembered that, in Method II., there is some uncertainty 

 about the lead correction. If the leads to the insulators and to the guard- 



