CONTRIBUTIONS FROM THE CHEMICAL LABORATORY 

 OF HARVARD COLLEGE. 



A REVISION OF THE ATOMIC WEIGHT OF 



MAGNESIUM. 



By Theodore William Richards and Harry George Parker. 



Presented May 13, 1896. 



Although numerous determinations of the atomic weight of magne- 

 sium have been made, the results obtained show such very wide variations 

 among themselves that the value in use at present cannot be accepted 

 with any certainty. It will not be necessary to review in detail all the 

 work published, as most of it was done more than forty years ago, before 

 quantitative methods had attained their present exactness ; but the follow- 

 ing table of methods used and results obtained will assist in a clear com- 

 prehension of the situation. 



Previous work on the Atomic Weight of Magnesium.* 



Synthesis of sulphate by the action of sulphuric acid on the oxide. 



Berzelius, 1826. Lehrbuch, 5th edition, IIL 1227 25.3 



Svanberg and Nordenfeldt, 1848. Erdmann's Journ. 



Prak. Chem., 1848, XLV. 473 24.7 



Bahr, 1852. Erdmann's Journ. Prak. Chem., 1852, 



LVL 310 24.8 



Marignac, 1884. Annal. Chim. Phys., 1884, (5.), L 



289, 321 24.37 



Conversion of sulphate into oxide. 



Jacquelain, 1851. Annal. Chim. Phys., (3.), XXXIL 



1 95 24.5 



Determination of sulphuric acid in sulphate. 



Gay-Lussac, 1820. Annal. Chim. Phys., XIIL 308 24.6 



* We are indebted to F. W. Clarke for most of tlie above references. 



