From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Test report continuation describing the electrostatic effect of earthing copper and iron tubes on spark length.
| Identifier | ExFiles\Box 61b\4\ scan0198 | |
| Date | 24th November 1919 guessed | |
| -2- Contd. If, however, the tube is earthed, the length of spark is considerably reduced owing to the capacity effect of the tube, also that it is reduced to the same extent for the copper tube as for the iron tube, shewing that the effect is wholly electrostatic within the limits of measurements. A similar test was made using a Remy 6 volt 12 cylinder coil, with running current considerably reduced from normal by the insertion of resistance, from which exactly similar results were obtained as follows :- Length of gap for regular sparking. Tube. Tube insulated. Tube earthed. None (Cable straight) .090" - Copper. .090" .035" Iron. .090" .035" " EFC. | ||