220 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 54 



Mean, 60.2815, ± .0027 

 Hence Mg = 24.287. 



The best determinations of all are those of Eichards and Parker/ 

 who studied magnesium chloride with all the precautions suggested by 

 the most recent researches. The salt itself was not only free from oxy- 

 chloride, but also spectroscopically pure as regards alkaline contamina- 

 tions, and all weighings were reduced to a vacuum standard. The first 

 series of experiments gives the ratio between silver chloride and mag- 

 nesium chloride, and I have reduced the data to the form 2AgCl : MgCL : : 

 100 : X. The weighings and values for x are subjoined : 

 MgCL. AgCl. Ratio. 



1.33550 4.01952 33.225 



1.51601 4.56369 33.219 



1.32413 3.98528 33.226 



1.40664 4.23297 33.231 



1.25487 3.77670 33.227 



Mean, 33.226, ± .0013 



Hence Mg= 24.335. 



The remaining series of experiments, three in number, relate to the ratio 

 2Ag: MgClo, which was earlier investigated by Dumas. For the elaborate 

 details of manipulation the original memoir must be consulted. I can 

 give little more than the weights found, and their reduction to the usual 

 form of ratio, 2Aor : MgCL, : : 100 : x: 



'Zeitsch. anorg. Chem., 13, SI. 1896. 



