408 Dr. C. R. A. Wright on the Relations between 



Now 



A 8 =0-24 (100-15) XxJro =0-0204, 



A 4 =3-407 (100-15) x T0 V D - =0-289, 



aDd A 5 = 0-218 (100-15) x^^ =0-0185 ; 



where 0*24 is the specific heat of carbon between 15° and 100°, 

 and 3'407 and 0*218 the specific heats under constant pressure 

 of hydrogen and oxygen respectively ; hence 



2SF 100 = 12m (7-964 + 0-0204) + rc(34-275 + 0*289) 

 + 16j_ x 0-0185 -23(1-1! + H 2 ) 

 = mx 95-813 -fwx 34-564 +__ x 0-296-28(H 1 + H 8 ). 



13. If, however, the carbon, hydrogen, and oxygen jointly 

 occupied the same volume as the resultant vapour, the heat ge- 

 nerated on coalescence at 100° would be less than this amount 

 by a quantity h 6 , representing the work done in compressing the 

 materials from the bulk occupied at 100° and 760 millims. to 

 that occupied by the compound vapour. Neglecting the space 

 occupied by the solid carbon, 



. , , , 273 + 100 _____ 76x13-6 

 h 6 = (n+p-2) -^3- x 11160 x g^ggg 



= (n+p-2)x 0-372, 



where w+j.t-2 is the number of metropneums of contraction 

 taking place when the constituent hydrogen and oxygen are 

 compressed into the same bulk as the resultant vapour. 



13*6 is the weight in grammes of one cubic centimetre of 

 mercury, and 42,350,000 is the mechanical equivalent in centi- 

 metre-grammes of the unit of heat employed, viz. 1000 calories. 



14. Hence, altogether, 



2SF ]00 =m x 95-813 + n x 34-564+^ x 0'296-25(H 1 + H 2 ) 



-(ti+jo-2)x 0-372, 



where H 2 is given by the formula 



H 2 = Sl (t -15) +/+_ 2 (100-_), 



s x being the specific heat of the substance in the liquid state 



between 15° and its boiling-point, t, 

 s 2 being the specific heat, under constant pressure, of the 

 vapour above the boiling-point, 

 and / the latent heat of vaporization at the boiling-point under 

 a pressure of 760 millims. 



