266 



Dr. Thomas Thomsons Observations 



their atomic numbers, making that of silicon 2 and that of 

 alumina 2*5. This would raise the atom of silica to 4 and 

 that of alumina to 4-5. Substituing these for the atomic 

 numbers in the table their product by the specific heat 

 gives us 0-716 and 0-874. 



The numbers in the third column of the table do not 

 cpuite agree with each other ; but there is such an approxi- 

 mation as to warrant the conclusion, that the deviations 

 are owing to errors committed in determining the specific 

 heats. The mean of the whole 16 gives 0738 as the pro- 

 duct of the atomic weight by the specific heat. Now, 

 0-375 x 2 = -750 which approaches pretty near the mean 

 found. 



From this it appears that the specific heat of all these 

 binary atoms is the same, and that it amounts to twice as 

 much as the quantity combined with the simple atoms. It 

 would seem from this that each of the atoms in the binary 

 compound retains all the heat with which it was united previous 

 to its entering into the state of a compound. 



The atomic numbers of Berzelius approach so near my 

 own in all these binary compounds except three, that it 

 is needless to compare them. The three exceptions may be 

 seen in the following little table. 



Atoms of 

 Berzelius. 



Specific 

 beat. 



Product. 



Oxide of chromium, . 10-03631 0-196 1-967 

 Sulphuret of mercury, . 27-3281 0-052 1-421 

 Sulphide of arsenic, . . 13-42414 0-11111-49 



The mean of these products is 1-626, which is rather 

 more than double the average deduced from the 16 binary 

 compounds. But Berzelius considers oxide of chromium 

 as a cpiarternary compound. Now 0-375 x4 = 1*5. The 

 other two he makes ternary compounds and 0*375 x 3 = 

 1*125. Numbers which deviate too far to admit us to adopt 

 Berzelius's atoms as the true ones. 



Let us now attend a little to the five binary compounds 

 at the end of table second. 



The atomic weight of water multiplied into its specific 

 heat gives 1-125. This number corresponds with that be- 

 longing to the ternary compounds. Now, we might con- 

 sider water as a compound of one atom oxygen and two 



