34: Messrs. Carnelley and O'Shea on Melting-points and 



From the above table it is seen that, by dividing tbe expe- 

 rimental boat of formation (N) by the number in tbe second 

 column (M), a nearly constant number is obtained, whicb is 



N 

 given in the last column. The mean of the numbers for ^ 



= 2*4(> or about 2*5, which latter has been assumed as correct. 

 On multiplying M by this number 2*5, we obtain the calculated 

 heats of formation as shown in the third column; and these 

 agree fairly well with the experimental heats of formation in 

 the fourth column. The bracketed numbers in the last column 

 represent those values of N which have been used in finding 



the constant ^» 



In the following table are given the percentage differences 

 between the calculated and experimental heats of formation : — 

 first (column I.), as referred to the experimental numbers given 

 in brackets in the last column of the preceding table ; and 

 second (column II.), to the nearest extreme experimental 

 number, when the calculated number is either greater or less 

 than all the experimental numbers. For comparison, there is 

 given in column III. the percentage difference between the 

 greatest and least of the experimental values reckoned on the 

 bracketed numbers in the last column of the preceding table. 





I. 



II. 



III. 





I. 



II. 



III. 



KOI 



1-9 



30 



20 



2-2 



100 



6-0 



13 



90 



160 



40 



6-0 



3-0 



33 



40 



25-0 



370 



8-0 



110 



27-0 



1-3 



30 







2-2 

 100 











90 

 160 



40 







2-4 



3-3 



2-3 

 25-0 

 37 



80 

 110 

 270 



4-4 



30 



12-0 



5-4 



110 



70 



16-0 



8-5 

 33 

 8-0 



19-0 

 



CdCl 2 



14-0 



90 



90 



25 



130 



90 



14-0 



14-0 



140 



9-0 



390 



11-0 



40 



240 



20-0 



1-1 







18-0 



150 



300-0 



14-0 

 9-0 

 90 

 



5-5 



90 



140 



140 



140 



9-0 



39-0 



11-0 







24-0 



20-0 



1-1 







18-0 

 150 







4-0 



7-0 



110 



7-3 



0-5 



150 



220 



150 







5-7 



NaCl 



CdBr 2 .. 



ZnCl 2 



KBr 



NaBr 



ZnBr 2 . 



LiOl 



Znl 



KI 



Cdl 2 . 



Nal 



PbCl 2 



TIC] 



SnCl 2 



TIBr 



PbBr . 



Til 



SnBr .. 



AgCl 



CuCl .. 



CuCl 



SnI 



CuBr 



Pbl 



AgBr 



SnBr 4 . 



Oul 



SnI 



Agl 



A1 2 C1 6 



Al 2 Br 6 



SbCL 



MgCl 2 



MgBr 2 



BaBr 9 



Al I 





PI 3 





Mean of all except PI 3 = 



11-0 



100 



80 



The average difference between the heats of formation as 

 found by experiment and by calculation from the melting- 



