Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

326 MOLESWORTH'S POCKET-BOOK Electrical Formulae, by Paget Higgs, LL.D,, C.E., and R. S. Bbough—continued. 5. The comparison of capacities. . d' sin. — , 2 n E S . d n ’ E * san. - With the reflecting galv. d' and d may be put „ . d' . d lor sin. — and sin, -. A z Standard-jar method: Let a — first discharge and an = nth discharge deflection of standard condenser charged from 8 to be measured; k — capacity of standard condenser; then S= K . . V« ~ 6. Line Testing. (Schwendler.) Let W = measured circuit resistance. w — measured conduction resistance. I = measured insulation resistance. Then the following inequality must hold, w < W < I. Let i = true insulation resistance. L = true conduction resistance of whole line. I = true conduction resistance up to re- sultant fault. r = true resistance of receiving instru- ment at distant station, corrected for temperature.