92 ProFessoi' Berzelius on Thorina, 



heated to redness, weighed 0.6754 grammes. The alkaline 

 hquid which passed through, being saturated with muriatic acid, 

 ■and precipitated by chloride of barium, gave 1.159 grammes 

 sulphate of barytes. In another experiment I obtained the 

 proportions — 



1.0515 thorina, 

 1.832 sulphate of barytes. 



To determine the number of atoms of oxygen it contains, I 

 analyzed the double sulphate of thorina and potash : 0.801 

 grammes of the salt in crystals were dried on the sandbath } 

 they became opaque milk-white, and lost 0.0365 grammes of 

 water. This loss was not increased by a heat which melts tin. 

 The remaining 0.7645 grammes were dissolved in warm water, 

 precipitated by caustic ammonia, and heated to redness. The 

 earth obtained, weighed 0.265 grammes : the solution which 

 was left gave, by the usual treatment, 0.3435 grammes sulphate 

 of potash ; so that the sulphuric acid, united to the earth, was 

 0.156, or the same as is contained in the sulphate of potash. 

 This analysis for the determination of the atomic weight affords 

 two grounds of calculation — namely, from the sulphuric acid 

 and from the sulphate of potash. Calculated from the former, 

 the atom becomes 851.3, from the latter 841.73 : the formerly 

 mentioned analysis of the sulphate gives — the first, 849.664, 

 and the second, 836.86; the mean of all four = 844,9, is pro- 

 bably nearest the truth. 



As alumina and the oxide of iron give, with sulphuric acid, 

 salts, in which the oxygen of the acid is only twice as great as 

 that in the base, and as these salts unite with sulphate of 

 potash in such a proportion that the quantity of sulphuric acid 

 in each of the component salts is equal, the same most likely 

 holds, also, in the case of thorina* — a circumstance here so 

 much the more probable, as the sulphate of thorina, thrown 

 down by boiling, seems necessarily to be a basic (sub) salt. 

 In this case, the earth contains three atoms of oxygen, and one 

 half more per cent, than is denoted by the preceding analysis, 

 I therefore analyzed the salt, which crystallizes by a spontaneous 

 evaporation from an acid solution of sulphate of thorina, but I 

 found the base and the acid to be here in the same ratio, the 

 water of crystallization only being very different. I digested 



* I put these in italics, because they are not in the original; though they seem 

 necessary to complete the sense. 



