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 Joseph Lucas Ltd. comparing their P.100 headlamp with an American C.M. Hall lamp.
| Identifier | ExFiles\Box 61a\2\ scan0095 | |
| Date | 15th July 1930 | |
| X1357 EFC2/AD. 15th July, 1930. Messrs. Joseph Lucas Ltd. Great King St.{Capt. P. R. Strong} Birmingham. Dear Sirs, We have received your further letter ref. X/LT/5. of the 11th inst, concerning the question of dimmer switch and C.5. dynamo output. At the moment however, we are writing to you more particularly on the question of head lamps. We have had occasion recently to examine, in the undersigned's laboratory, an American make of head lamp manufactured by the C.M.Hall Lamp Co. Detroit, Michigan U.S.A. and as this appears to us to incorporate a number of good points we venture to put these forward for your consideration. The head lamp is of light weight, only 7 lbs. The front is sealed against weather by means of a cork ring between the front glass and the reflector, whereas the Lucas P.100 lamp depends upon two rubber seals which do not allow the reflector to keep bright as we think we have already previously mentioned to you. The glass of the Hall lamp is easily removed from the rim by spring clips, whereas the Lucas glass is "peaned" in. The focus of the Hall lamp is adjustable without obstructing the beam or removing anything. The Lucas front has to be opened and adjustment made inside. The Lucas however, is adjustable by hand whereas the Hall is adjusted by a screw driver at the rear. | ||