Platinum Resistance-Thermometers

Abstract

AT the meeting of the British Association, just coming to an end, it was pointed out to the Committee of Section A, by Mr. E. H. Griffiths, that the general adoption of the method of thermometry, founded on the variation of the electric resistance of platinum with temperature, that has been worked out by Prof. Callendar and himself, is seriously hindered by the existence of a report presented to the Belfast meeting of the Association in 1874 (British Association Report, 1874, pp. 242-249), by a Committee “appointed for the purpose of testing the new pyrometer of Mr. Siemens.” As I was secretary of this Committee and drafted the report, and as all the experiments were made either by myself or under my direction, I was desired by the Committee of Section A to ask you to allow me to state in the columns of NATURE (what is indeed obvious to anyone who refers to the 1874 report) that the tests carried out by the Committee of 1874, and the conclusions arrived at by them, had reference solely to the pyrometers supplied to them for examination by Messrs. Siemens Brothers, and that they have consequently no bearing on the question of the trustworthiness or accuracy of the platinum resistance-thermometers of the kind devised by Messrs. Griffiths and Callendar.