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).
Re-test report on a Runbaken syringe hydrometer, comparing its accuracy against standard Twaddell hydrometers.
| Identifier | ExFiles\Box 44\5\ Scan067 | |
| Date | 31th October 1923 | |
| EFC. COPY 31.10.23. RE TEST ON RUNBAKEN SYRINGE HYDROMETER. This hydrometer was compared with the standard Twaddell hydrometers in various strengths of acid, for accuracy in reading. The results are as tabulated below:- Twaddell. Std. S.G. Runbaken. 65 1325 1300 60 1300 1280 56 1280 1250 44 1220 1215 35 1175 1170 31 1155 1150 By these results it will be seen that the Runbaken hydrometer reads lower than the std. for the greatest error being .030 low and the smallest being .005 low. Good Points. (1) It is small and can easily be carried in the pocket when in the case. (2) The barrel is made of one-piece clear celluloid tube and will therefore not break or crack at joints. (3) The bulb is of good rubber and only needs compressing slightly to get sufficient acid for a reading. Bad Points. (1) A ring of celluloid is fixed inside the barrel so that the float cannot fall out, but at the same time the float cannot be taken out to allow for cleaning. (2) The dark colours on the float, with the small black density readings on them make it hard to take a reading, the eyes having to be strained to observe the figures at the acid level. Contd. | ||