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).
Certificate of assay for two contact points identifying the material as metallic tungsten.
| Identifier | ExFiles\Box 35\5\ scan 058 | |
| Date | 28th July 1919 | |
| X.2894 X.1818 RB{R. Bowen}/271/29½ Assay Offices & Ore Floors. Hatton Garden, London. E.C. 28th July, 1919. X.1818 CERTIFICATE OF ASSAY. X.2894 -------------------- ------- For Messrs. Rolls-Royce Ltd. Nightingale Road, Derby. We have assayed the Two Contact Points. as under and find the following to be the result. 2 Contacts. 2.79 grains. 2.74 grains. ---------------------------------------- These Contacts are Metallic Tungsten For Johnson, Matthey & Co. Ltd. | ||