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).
Tests on annular spark gaps under various conditions.
| Identifier | ExFiles\Box 54\3\ Scan245 | |
| Date | 21th October 1924 | |
| X4645 21.10.24. X.4645. ANNULAR SPARK GAPS UNDER VARIOUS CONDITIONS. Dia. of central electrode. Diameter of hole. Remarks. .087" .312" (3.59)(2). Invisible Coronal discharge prior to breakdown. .087" .325" (3.74)(1) Invisible coronal discharge. .100" .312" 3.12 (4) Invisible comal discharge. .100" .325" 3.25 (3) Invisible coronal discharge. .125" .312" 2.50 (6) Slight invisible coronal discharge. .125" .325" 2.60 (5) Slight invisible coronal discharge. EFC. | ||