1818.] the Atoms of Chemical Bodies, 343 



Weight of an atom. 



21 Lime 3-625 k 



22 Barytes 9-750 ! 



53 Strontian 6-500 m 



24 Magnesia 2-500 n 



25 Yttrium 4-000 



26 Yttria 5-000 







k If sulphate of lime be a compound of 5 acid + 3-625 lime, 

 its constituents will be 



Acid. Lime. 



57-97 + 42-03 

 Berzelius's analysis gives us 58*00 + 42-00 



which maybe considered as an exact coincidence. 



1 If sulphate of barytes be composed of 5 acid + 9 - 75 barytes, 

 its constituents will be 



Acid. Barytes. 



33-90 + 66-10 



Mr. Arthur Aikin's analysis gives 33*96 + 66-04 



Berzelius and Fourcroy found 34-00 -f- 66-00 



m Carbonate of strontian, supposing it a compound of 2-75 

 acid + 6*5 strontian, should consist of 



Acid. Strontian. 



29-73 + 70-27 

 I found its constituents to be 29-90 + 70-10 



If sulphate of strontian be a compound of 5 acid + 6'5 stron- 

 tian, its constituents should be 



Acid. Strontian. 



43-48 + 56-52 

 Stromeyer found it 43*00 + 57*00 



These coincidences are sufficiently near. The deviations are on 

 opposite sides ; so that the mean of the two would almost tally 

 with our theoretic number. 



Acid. Magnesia. 



n Berzelius found sulphate of magnesia com- 7 fj^.rA i •^••"ifi 

 posed of. 5 



If it be a compound of 5 acid + 2*5 mag- 7 pp.fjn . qo.oq 

 nesia, its constituents will be 5 



This coincidence I consider as exact. 



° According to Berzelius (Afhandlingar, iv. 236), sulphate of 

 yttria is composed of equal weights of acid and base. Hence 

 an atom of yttria weighs the same as an atom of sulphuric acid. 

 The weight of an atom of yttrium is conjectural. It is founded 

 on the supposition that yttria is a compound of 1 atom yttrium 



