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 from Joseph Lucas Limited discussing the performance of double filament headlamp bulbs.
| Identifier | ExFiles\Box 61a\1\ scan0240 | |
| Date | 25th August 1926 | |
| CONTRACTORS TO THE ADMIRALTY, WAR OFFICE, AIR MINISTRY, INDIA OFFICE, G.P.O. AND LEADING RAILWAYS. Codes: A.B.C. 5TH & 6TH EDITN & BENTLEYS. TRADE MARK 'KING OF THE ROAD' LAMPS, HORNS, 'CYCLEALITIES', 'MOTOR CYCLEALITIES', 'MOTORALITIES', MAGNETOS, BATTERIES, ELECTRIC LIGHTING & STARTING SYSTEMS. JOSEPH LUCAS LIMITED GREAT KING STREET BIRMINGHAM SERVICE DEPÔTS BIRMINGHAM. GT. HAMPTON STREET. BRISTOL. 25 TEMPLE STREET. COVENTRY. PRIORY STREET. GLASGOW. 227, ST GEORGE'S RD. LONDON. SCRUBBS LANE, WILLESDEN, N.W.10. LONDON. 155, MERTON ROAD, WANDSWORTH, S.W.18. MANCHESTER. CHESTER ROAD, STRETFORD. NEWCASTLE-ON-TYNE. 68, ST.{Capt. P. R. Strong} MARY'S PLACE. WHOLESALE DEPÔTS BRISTOL. 25, TEMPLE STREET. DUBLIN. TAYLOR BROS. 41, MIDDLE ABBEY STREET. GLASGOW. 227, ST.{Capt. P. R. Strong} GEORGE'S ROAD. LONDON. 224, SHAFTESBURY AVENUE, W.C.2. MANCHESTER. 277, DEANSGATE. NEWCASTLE-ON-TYNE. 68, ST.{Capt. P. R. Strong} MARY'S PLACE. TELEPHONES: NORTHERN 2201 (PTE. BCH.{F. H. Birchmore - Chassis Delivery Manager} EX.). TELEGRAMS & CABLES: 'LUCAS, BIRMINGHAM'. WHEN REPLYING PLEASE REFER TO OL/FEA. Messrs. Rolls-Royce Ltd., D E R B Y. 25th August, 1926. Handwritten text at top: #1575 X S200 Stamped text in middle: X1369 Dear Sirs, Your Ref. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}3/T - Headlamps. In reply to your letter of the 23rd August, giving us an extract of a letter you received in connection with the double filament bulbs, we would say that we are fully aware of this type of device and have tried it out ourselves. We do not find however, that the results are quite as favourable as one would be led to believe by your American friends. We have much pleasure in sending for your own confirmation or otherwise, several bulbs having this double arrangement of filament which we have been using for our own experiments. Some of these are exactly similar to the American bulbs except that they are made for a 12 volt circuit. Have you tried the double filament type of bulb having an internal shield arranged to obscure half the light given from one filament? When this is carefully arranged in the reflector the results are very effective. You get the main driving | ||