XVI INTRODUCTION. 



convert It to the corresponding value on the Kelvin scale. These correc- 

 tions will differ according to the kind of thermometer used in obtaining the 

 value f , and while they are small for temperatures between 0° and 100° 

 they are large at extreme temperatures and are important in all questions 

 involving thermometric precision. 



Since, however, the approximate absolute scale is sufficiently exact for 

 nearly all purposes, and especially since it is most convenient in computa- 

 tions and in the publication of results, much confusion and uncertainty of 

 terminology and meaning will be obviated if scientists will agree to give 

 the approximate absolute scale a particular name of its own. 



For the purpose of these tables the name Approximate Absolute will be 

 employed, and in accordance therewith thermometric scales may be desig- 

 nated as follows: — 



Scale. Ice point. Boiling point. Symbol. 



Centigrade 

 Fahrenheit 

 Reaumur 



Thermodynamic 



-^ , . 1 (Names strictly synon\'mous and strictly 



Kelvm -11 1 



one ideal scale. 



Approximate Absolute 273 373 A. A. 



Table 1 . Conversion of the Approximate Absolute thermometric scale to the 

 Centigrade, Fahrenheit, and Reaumur scales. 



The equivalent values of the four scales are given for every degree on 

 the Approximate Absolute scale from 375° to 0°. 



By the help of the table of proportional parts preceding this talile, it 

 is also convenient for converting Fahrenheit to Centigrade and Reaumur, 

 and Centigrade to Fahrenheit and Reaumur. 



The formulae expressing the relations between the different scales are 

 also given, in which 



A.A.° = Temperature — Approximate xA^bsolute Scale. 

 C° = Temperature — Centigrade Scale. 

 F.° = Temperature — Fahrenheit Scale. 

 R° = Temperature — Reaumur Scale. 

 Examples : 



To convert 285°5 Approximate Absolute into Centigrade, Fahrenheit, 

 and Reaumur. 

 From the table, 285? A. A. = 12? C. = 53?6 F. = g% R. 



From the proportional parts, 0.5 = 0.5 = 0.9 = 0.4 



285.5 A.A.= 12.5 C. = 54.5 F. = lO.oR. 



