Combination of Sulphuric Acid and Water. 265 



liquids, and place beside them the multiples of 0-375, 

 which represent the specific heat of these liquids. 



From this table it appears 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 

 0375 X 7 (the number of atoms), is only 0*375 x 6. So 

 that one of the atomic constituents is deprived of the whole 

 of its heat : in other words one-seventh part of the whole 

 heat is disengaged. This portion, by experiment, amounts 

 to 185° ; so that the whole heat in the oil of vitriol and 

 water before combination must have been 1295°. 



When one atom of (one acid + two water is mixed with 

 one atom of water, the heat of the compound is less than 

 0*375 X 13 (the number of atoms) by 2. But, the com- 

 bination of 1 oil of vitriol and 1 water is less by 1. Hence, 

 in this second combination, the real diminution is only 1; 

 so that the heat evolved should be ^^th of the whole. I 

 found it only 70°. But the experiment was made upon too 

 small a scale. When the experiment was made by mixing 

 24 cubic inches of oil of vitriol with the requisite quantity 

 of water to constitute a compound of (1 atom acid + 3 

 atoms water), the heat evolved was 219°, Now, if this be 

 ^\ths of the whole heat as it ought to be from the table, 

 the whole heat would amount to 1423°*5. By the second 

 experiment in which the heat evolved was 70°, the whole 

 heat would amount to 1110°. Now the mean of these two 

 numbers is 1266°, which nearly agrees with the deduction 

 from the mixture of oil of vitriol with one atom of water. 



