1821.] Strontian, Lime, Magnesia, Phosphoric Acid, S^c. S* 



Strontian 6-4730 ^ 



Lime 3*5603 



Magnesia 2-5836 



Phosphoric acid 4-4615 



Arsenic acid 7-20385 



When thus stated, they approach very nearly to the other 

 «Ltomic numbers contained in the table, though the number of 

 decimal places is sufficient to render their absolute accuracy 

 auspicious. They want one of the criterions which 1 have 

 shown, in my preceding papers, that the real atomic weights of 

 bodies possess. They are none of ihem multiples of 0-125, the 

 weight of an atom of hydrogen. Dalton's numbers were obtained 

 by dividing the atomic weights which he gives in his System of 

 Chemical Philosophy by 7, which is his weight of an atom of 

 oxygen. This is a fairer method than the one which I employed 

 in my last paper. I there took in his error with respect to the 

 weight of oxygen when compared with hydrogen. Here that 

 «rror is not reckoned at all, but tacitly corrected. 



Let us now have recourse to experiments to determine which 

 of these columns comes nearest the truth, or whether any of 

 them be absolutely correct. Sulphate of soda is composed an 

 follows : 



Sulphuric acid 5 



Soda -*,^-r'ff '^ ^ 



Sulphate of soda 9 



According to the numbers which 1 have made choice of for 

 •chlorine and strontium, chloride of strontium is composed of 



Chlorine 4-5 



Strontium 5'5 



Chloride of strontium 10*0 



To determine whether these numbers be correct, I took nine 

 grains of sulphate of soda recently kept for half an hour in the 

 «tate of igneous fusion, and dissolved it in a small quantity of 

 distilled water. 1 likewise dissolved in another portion of 

 distilled water 10 grs. of chloride of strontium, recently fused 

 and perfectly dry. These two liquids were carefully mixed 

 together, and allowed to remain in contact for 24 hours. I then 

 drew off a portion of the clear liquid, and examined it. No 

 change whatever was produced in it by nitrate of barytes. Of 

 course, it contained no sensible quantity of sulphuric acid. It 

 was not rendered in the least turbid by sulphate of soda, phps- 

 phate of soda, arseniate of soda, or chromate of potash. Hence 

 there is no evidence that it contained any strontian. » 



I consider myself as warranted by the preceding experimeat 

 tO'Conclude, that chloride of strontium is composed of - - 



