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THE 



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Thermometers 



By FRED G. ORSINGER. Chicago. 



Since foreign contemporaries use and 

 quote other than the Fahrenheit ther- 

 mometer, so generally used by our mem- 

 bers, a short discussion of the various 

 systems used was considered of interest. 



Thermal or Heating value is that prop- 

 erty by virtue of which a body has for 

 absorbing or giving off heat. 



Thermometer — An instrument for 

 measuring temperatures, but very often 

 supposed to be a heat measure. This 

 latter is, however, erroneous, as it is in 

 no sense a measure of heat, but gives 

 simply a relative comparison as to the 

 degree of heat in the body or fluid 

 measured; that is, a thermometer regis- 

 tering 1 75 degrees in one body, while in 

 another a thermometer registers 50 de- 

 grees, indicates that one body is 125 

 degrees warmer than is the other. 



The Fahrenheit thermometer was in- 

 troduced by Gabriel Daniel Fahrenheit, 

 in 1724. It is used in America and 

 Great Britain and the British Colonies. 

 The number degrees or zero on the 

 scale corresponds to the lowest degree 

 of cold that could be artificially pro- 

 duced when the thermometer was orig- 

 inally introduced. 



The freezing point of water is taken at 

 32 degrees above zero, and the tempera- 

 ture of pure boiling water at 212 de- 

 grees. In both cases the measurement 

 is recorded under the ordinary atmos- 



pheric pressure of 14.7 pounds per 

 square inch. 



Between 32 and 212 degrees there are 

 180 degrees, which are usually spaced 

 into 1 -degree intervals. 



The Centigrade thermometer, which 

 was designed by Anders Celsius, a Swed- 

 ish astronomer in 1742, and in Germany 

 is known as the "Celsius" and also 

 "Centigrade" and indicated as "C" is 

 used in Europe and in scientific work 

 generally. degrees or zero corresponds 

 to the freezing point, or melting ice 

 (which is marked 32 on the Fahrenheit 

 scale) and 100 degrees to boiling water. 

 From the freezing to the boiling point 

 there are 100 degrees. 



Rene Antoine Ferchault de Reaumur 

 introdviced, in 1730, the thermometer 

 which bears his name. It is used in 

 Russia, Sweden, Turkey and Egypt. 

 degrees or zero, corresponds to melting 

 ice, 80 degrees to boiling water. From 

 the freezing to the boiling point there 

 are 80 degrees. 



Each degree of Fahrenheit is 5/9 of a 

 degree Centigrade, and 4 9 of a degree 

 Reaumur. 4^he Centigrade temperature 

 interval between the freezing and the 

 boiling point being 100 and the Fahren- 

 heit interval 180, it follows that 1 de- 

 gree Centigrade is c(iual to 1 .S degrees 

 Fahrenheit. 



Centigrade temperatures are convert- 

 ed into Fahrenheit's scale by multiply- 

 ing the former by 9 and dividing by 5, 

 and adding 32 degrees to the ([uotienl; 

 and conversely, Fahrenheit tempera- 

 tures are converted into Centigrade scale 

 by deducting 32 and taking 5 9 of the 

 remainder. 



ilxamph : 



Centigrade Degrees — 20 X 9 =36 and 

 36 + 32 68 degrees F. 5 



Fahrenheit Degrees: 68—32=36 and 

 36X5 20 degrees C. 



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