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).
Letter to G.E.Co. Ltd. regarding the specifications and purpose of double-filament Bifocal Lamps.
| Identifier | ExFiles\Box 61a\1\ scan0372 | |
| Date | 24th October 1928 | |
| X 4477 copy sent to their London addresss. EFC7/T. 24th October, 1928. Messrs. The G.E.Co. Ltd., 34/35 Moor Street, Birmingham. Dear Sirs, With reference to the enquiry sent by our G.O. ref. ROY{Sir Henry Royce}/FL/R.18. of the 18th inst., for Bifocal Lamps, and your answers ref. O/P.446 of the 19th inst. from your Birmingham House, and FHL/S. of the 23rd inst. from your Kingsway House, this matter is having consideration. In the meantime we wish to say that we have in our stock two lamp bulbs of your manufacture which have double filaments and double contact caps with common filament connection on the cap. The axis of one of the two filaments coincides with the axis of the bulb, whereas the other one is displaced to one side. Each of these filaments is 12 Volts, 36 Watts, the bulb being marked "12/14 V.{VIENNA} 36 W. Osram Twin Filament, Gasfilled, G.E.C. Patent". We should be pleased, before going to the extent of altering the lampholder in the P.100 Lucas lamps with a view to taking these, to know from you for what purpose these lamps were made, as it appears to us they were made for bifocal dipping. Yours faithfully, * Previous corres X.1357. FOR ROLLS-ROYCE LIMITED. | ||