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 Examination for Dial thermometer No. 1633, detailing scale reading corrections.
| Identifier | ExFiles\Box 40\1\ Scan053 | |
| Date | 4th October 1923 | |
| No. 4249 Certificate of Examination. X.3695 Corrections to be applied to the Scale Readings of Dial thermometer No. 1633 BY NEGRETTI & ZAMBRA, determined by comparison with Standard Instruments verified at the National Physical Laboratory. at -10° -.15° At 60° +.1° 0° -.15° 70° +.15° +10° -.05° 80° +.15° 20° 0° 90° 0° 30° 0° 100° +.1° 40° +.1° 110° +.1° 50° +.05° Centigrade Note.—I.—When the sign of the Correction is +, the quantity is to be added to the observed reading, and when — to be subtracted from it. II.—Mercurial Thermometers are liable, through age, to read too high ; this instrument ought, therefore, at some future date, to be again tested at the melting point of ice, and if its reading at that point be found different from the one now given, this difference should be applied to any corrections shown above. 38, HOLBORN VIADUCT, LONDON, E.C. 1. 4th October 1923. Negretti & Zambra | ||