Letter from John J. Griffin & Sons, Ltd. regarding the testing of condensers.
| Identifier | ExFiles\Box 34\1\ Scan314 | |
| Date | 14th August 1922 | |
| JOHN J.GRIFFIN & SONS, LTD MAKERS OF PHYSICAL, ELECTRICAL & SCIENTIFIC INSTRUMENTS. CHEMICAL APPARATUS. CHEMICALS & REAGENTS. TELEPHONE: GERRARD 2621 (3 LINES) TELEGRAMS: GRAMME, WESTCENT, LONDON. A.B.C. CODE 5TH & 6TH EDITIONS. ENCLOSURES KINGSWAY, (CORNER OF KEMBLE STREET) LONDON, W.C.2. 14th August, 1922. ALL COMMUNICATIONS TO BE ADDRESSED TO THE FIRM. IN ANY REPLY PLEASE QUOTE H.P./D Messrs. Rolls-Royce Limited, Nightingale Road, Derby. Dear Sirs, In reply to yours of the 4th inst., we have gone very carefully into the question of testing Condensers of the magnitude you mention by galvanometer methods, but have not been able to get satisfactory results even with our most sensitive suspended coil instrument. We are of opinion that the only satisfactory means of comparing Condensers of low values of 0.001 to 0.05 would be the high frequency method involving the use of a thermionic valve and a double telephone headgear. We are unable to quote you a firm price for such apparatus but the cost would be considerable. We shall be pleased to go further into the matter should you wish us to do so. Yours faithfully, JOHN J. {Mr Johnson W.M.} GRIFFIN & SONS LTD. [Handwritten Notes & Stamps] Blue ink initials: Wd {Mr Wood / Mr Whitehead} Red Stamp: NATIONAL SCHEME FOR DISABLED MEN Purple Stamp: RECEIVED AUG 15 1922 Red pencil initials: EAC Handwritten pencil note: S7C4/T3.8.22 | ||
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).