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).
Testing of Philips Cadmium Yellow bulbs and various headlamp dipping and switching schemes for R-R and Bentley chassis.
| Identifier | ExFiles\Box 61a\2\ scan0386 | |
| Date | 6th November 1934 | |
| S/W. Hs{Lord Ernest Hives - Chair}/Wst. c. to Sg.{Arthur F. Sidgreaves - MD} W or. c. " C. E.{Mr Elliott - Chief Engineer} c. " Bl. WST Cx{Major Len W. Cox - Advertising Manager}7/KW6.11.34. Headlamps and Foglamps for R-R and Bentley Chassis. regarding the above. I was very interested in your Hs{Lord Ernest Hives - Chair}/Wst5/MA.1.11.34 When you carry out these tests I wonder if you would care to try the effect of the Philips Cadmium Yellow bulbs as mentioned in the enclosed advertisement. Sg{Arthur F. Sidgreaves - MD} sent me this many months ago, and I have kept it until the approach of Winter and probably foggy days, and it does seem to be a good opportunity for you to ascertain if there is anything in the claim made for these. You will notice the advertisement says that Cadmium Yellow light penetrates fog to a greater degree than that of any other type of motor bulb. As we all feel that there is room for some improvement in the lighting used in our cars in view of regulations and the necessity for efficient anti-dazzle, etc., we welcome the tests you are about to carry out. We also still feel very strongly that we may be forced into the dip and switch scheme because of the lack of response to a scheme where both the headlamps remain alight even though dipped, and we would be glad if you would include such a scheme in your experiments. The weakness of this scheme in our view when we tried it previously in London with two cars, one with the dip and switch scheme and one with the double dip scheme, was that there was insufficient light when one of the headlamps was switched out. Possibly a dip and switch scheme could be arranged whereby if there is not sufficient light for safe driving at night - particularly when the roads are wet and dark - with only one headlamp left when the offside headlamp is switched out and the nearside one dipped, a centre spot lamp could be introduced into the scheme, so that the spot lamp would be directed to the nearside and the headlight would not dip quite so much as otherwise would be the case. Enc. Cx.{Major Len W. Cox - Advertising Manager} | ||