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 discussing the adoption and types of fixed focus two-filament headlamps.
| Identifier | ExFiles\Box 61a\1\ scan0419 | |
| Date | 3rd December 1928 guessed | |
| 2 As mentioned in a previous letter, fixed focus two-filament headlamps will no doubt grow in popularity and are being adopted as standard for Chevrolet and Whippet, this next year. For your equipment, however, I believe that a focusing adjustment would be more satisfactory. No doubt, you are considering a type of lamp which has in addition to the main light source, an auxiliary of three or six candlepower for pakring. In connection with the 21-21 candlepower lamp, you might be interested in trying out the 32-21 which gives a considerably better driving beam. Thirty-two candle-power lamps are not legal in all states, but wherever they can be used in modern types of equipment such as the one which you are considering, there is a material improvement in road lighting. I hope the above gives the information which you desire. Yours very truly, (Signed) R.E. Carlson. IN CHARGE OF AUTOMOTIVE LIGHTING | ||