RAIRD &1ATLOCK (LONDON) LTD. 



SECTION No. 17. 



Water and Electrical Pyrometers for the 

 Measurement of High Temperatures. 



JFtgL 



5383 (Section) 



Siemens' Water Pyrometer. 



The pyrometer is shown in sections in the accompanying sketches. It consists of a cylindrical copper vessel provided with 

 a handle, and containing a second smaller copper vessel with double walls. An air space, a, separates the two vessels, and a layer 

 of felt the two walls of the inner one, in order to retard the exchange of temperature with the surroundings. The inner vessel 

 holds a little over one pint of water. A mercury thermometer, b, is fixed close to the wall of the inner vessel, its lower part being 

 protected by a perforated brass tube, whilst the upper projects above the vessel and is divided as usual on the stem into degrees, 

 Fahrenheit or Centigrade, as desired. At the side of the thermometer there is a small brass scale, c, which slides up and down, 

 and on which the high temperatures are marked off in the same degrees into which the mercury thermometer is divided ; on a 

 level with the zero division of the scale a small pointer is fixed to it, which passes in front of the thermometer. 



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