60 



SIXTH RKrORT 1836. 



The last column shows to what number multiplied bj' 0'375, the 

 product of the atomic weight by the specific heat is equal. These 

 numbers approximate to 3, 6, 9, 11, 13, 16, 19, 22, 25, 28, and 31 ; and 

 Dr. Thompson thinks it probable that if the experiments on the specific 

 heat of these compounds had been perfectly accurate, there would have 

 been the exact numbers, which, multiplied by 0'375, would have re- 

 presented the product of the atomic weight into the specific heat. 



Now, sulphuric acid is a compound of one atom sulphur and three 

 atoms oxygen, so that an integrant particle of it contains four atoms. 

 British chemists, in general, consider water as a compound of one atom 

 oxygen and one atom hydrogen ; but the continental chemists consider 

 it as a compound of one atom oxygen and two atoms hydrogen, con- 

 sidering the number of volumes as measuring the number of atoms. 

 Many unanswerable reasons might be given for adopting this last con- 

 clusion as the true one. If, then, we admit that sulphuric acid con- 

 tains four atoms, and water three atoms, we may compare the number 

 of atoms in each compound with the multipliers of 03 75, which 

 represent the product of the atomic weight of each into its specific 

 heat. This is done in the following table. 



From this table it is evident that when an integrant particle of oil 

 of vitriol is combined with an integrant particle of water, the specific 

 heat of the compound, instead of being 0-375 x 7, is only 0-375 x 6 ; 

 so that jth of the whole heat is thrown out. This amounts to 185°. 

 We see from this the cause of the evolution of heat, and we see at 

 the same time that the whole heat which existed in the water and oil 

 of vitriol before combination was 185 x 7 = 1295°. 



When an integrant particle of acid, composed of (1 acid -|- 2 water) 

 is mixed with a particle of water, the heat of the compound is less than 

 0-375 X 13, by 0375 x 2. In this case y-^jths of the heat are evolved. 

 When an integrant particle of acid composed of ( 1 acid + 3 water) is 

 mixed with a particle of water, the heat of the compound, instead of 

 being 0375 x 16, is only 0375 x 13, or fgths of the heat are evolved. 



