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).
Instructions and advice regarding the correct usage of a Hobson Petrol Gauge.
| Identifier | ExFiles\Box 44\3\ Scan156 | |
| Date | 15th January 1929 | |
| To Mx.{John H Maddocks - Chief Proving Officer} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} X4038 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG15.1.29 HOBSON PETROL GAUGE. X8460 With reference to Mx{John H Maddocks - Chief Proving Officer}/McM10/T7.1.29. We think the instructions in the label are quite good. We think however you should state positively that - "the front end of the air line should never be disconnected under any circumstances until the rear end of the line has been detached from the tank". Also with regard to the initial pumping up of the gauge. The correct way to start the gauge off is to empty the tank completely and couple up the gauge as specified on your lable and then fill the tank about half full. The gauge should then read correctly the amount of petrol in the tank. If the gauge is connected up initially when there is some petrol in the tank, the car will have to run a considerable distance on the road before a correct reading is obtained. Therefore every time it is found necessary to uncouple the gauge, the best practice is to empty the tank before re-coupling. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||