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).
Test report on 24 Exide Type S1 hydrometers, noting the absence of float spikes.
| Identifier | ExFiles\Box 44\5\ Scan099 | |
| Date | 31th January 1928 | |
| X 3741 To BY/HM.{Capt. W. Hallam - Head Repairs} from EFC. EFC5/T31.1.28. 24 EXIDE TYPE S1 HYDROMETERS HANDED TO US FOR TEST REPRESENTATIVE OF 10% OF PRODUCTION. We have carefully checked these against our standard floating type hydrometer and we find every one of them to read reasonably accurately and to show no particular faults. We notice, however, that the floats of these hydrometers are not now provided with the spikes to prevent the phenomenon which sometimes we noticed of the float sticking to the side of the main hydrometer tube, and thus giving incorrect readings. Instead of having these spikes they are smooth. We carefully watched for any sticking, but did not observe anything of this nature, though we should have thought from our previous experience that the provision of the spikes was a definite improvement. We think it might be just as well to have the Exide Co.'s confirmation that the spikes have been definitely discarded as being unnecessary. There may even be some reason against the provision of these. We have already sent to you these 24 hydrometers. EFC. | ||