( 514 ) 



dp 

 for the nnantitv ^, doiivod hv A.ma(;at from tlio isotherm is not 

 ' f>,. 



coiistjint, which points to the tact thai Ity assiimiim- the constants 

 independent of the teniperatnre, no {)crfect agreement with the 

 observations will be obtained. 

 By means of the formnla: 



dp_i l ^a)(l-b^).a 

 dt„ V — b 



whicli is derived from tlie equation of state, when tlie constants are 



put independent ot the temperature, I liave determined the ^— for 



dt 



different vohimes, and compai-ed these vahies with tliose found by 



A MAG at/) 



TAB L E II. 



dp 



Iji the third cohimu ot tabh' II the values of — are 0:1 ven derived 



by Amagat from his detei'miuation of isotherms at 0'' and at 100', in 

 the fourth column the calculated \alues, and in the fifth the devia- 



dp 

 tions expressed in per cents ot ,— . 



dp 



If b\ means of the formula for -- we calculate from the pressure 

 at 15°, 7 the [)ressure at 25'. then the deviation of 0,0 " „ in the 



-— passes into one ot 0.04 " „ in the jtressure tor the \'olume 9730. 



dt^ ^ » i 



The devialioji of ihe p iutroihiccd iu this way, is smaller than 



1) 1. c. Table 2G. 



