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LVIII. Electrical Recording Thermometers for Clinical Work. 

 By H. L. Callendar, M.A., LL.D., F.R.S., Professor of 

 Physics at the Imperial College of Science and Technology y 



s. w* 



In Memoriam Dr. A. GAMGEE, F.R.S., obiit Mar. 29, 1909. 



1. FTTEE scientific interest and importance of a method 

 _L o£ continuously recording the temperature of the 

 body, whether in health or disease, is now being generally 

 recognized, and I have been persuaded that my experiments 

 in the construction and testing of suitable apparatus for the 

 purpose may be of some value at the present juncture, 

 although I have no results of physiological importance to 

 produce. 



My attention was first directed to the subject by Professor 

 J. G. Adami, F.R.S., of McGill College, Montreal, at whose 

 suggestion I constructed some electrical resistance thermo- 

 meters specially adapted for recording the temperature of 

 different parts of the suface of the body. Unfortunately I 

 had to leave Montreal early in 1898, before the apparatus 

 had taken its final shape, and the results obtained at that 

 time, consisting merely of experimental records of my own 

 normal temperature, did not seem to be of sufficient interest 

 to merit publication. I did not return to the subject until 

 November 1908, when I undertook to make some thermometers 

 for Dr. A. Gamgee, F.R.S., and to collaborate with him in 

 evolving a practical method suitable for general use in clinical 

 work. His paper, then recently published, " On Methods 

 for the Continuous (Photographic) and Quasi- Continuous 

 Registration of the Diurnal Curve of the Temperature of the 

 Animal Body " f , dealt exclusively with thermoelectric 

 methods of temperature measurement : but he had become 

 convinced that the thermoelectric method was unsuitable for 

 general use, on account of the delicacy of the apparatus, and 

 the necessity for employing an elaborate thermostat. The 

 Copper-Constantan thermocouples which he employed gave 

 an E.M.F. of 40 microvolts per 1° C, which was ample for 

 delicate photographic methods of registration, but insufficient 

 for the more robust type of instrument required for general 

 use with ink records. A more serious difficulty in practice 

 was the necessity of keeping one of the junctions of the 

 couple at a constant temperature in the neighbourhood of 



* Communicated by the Physical Society : Presidential Address^. 

 February 11, 1910. 



t Phil. Trans. Roy. Soc. B. vol. 200, p. 219 (1908). 



