216 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



After applying corrections for loss and retention of COo, as previonsly 

 inflieated, tlie mean results of the foregoing series become — 

 CO.. MgO. FeO. 



51.9931 47.2743 .7860 



The ratio between the MgO and tlie COo, after correcting for the iron, 

 will be considered further on. 



Of the white magnesite from Snarnm but a single analysis was made, 

 which for present purposes may be ignored. As for the Frankenstein 

 mineral three series of analyses were executed. In the first series the 

 following results were obtained : 



8.996 grm. CO, = 8.2245 grm. MgO. 47.760 per cent. MgO. 



7.960 " 7.2775 " 47.761 



9.3265 " 8.529 " 47.767 



7.553 " 6.9095 " 47.775 



Mean, 47.766, ± .0022 



This mean, corrected for loss of COo in drying, becomes 47.681. I give 

 series second with corrections applied : 



6.8195 grm. MgCOj gave 3.2500 grm. MgO. 47.658 per cent. 



11.3061 " 5.3849 " 47.628 



9.7375 " 4.635 " 47.599 



12.3887 " 5.9033 " 47.650 



32.4148 " 15.453 " 47.674 



38.8912 " 18.5366 " 47.663 



26.5223 " 12.6445 " 47.675 



Mean, 47.650, ± .0069 



The third series was made upon very pure material, so that the cor- 

 rections, although a]iplied, were less influential. The results were as 

 follows : 



4.2913 grm. MgCO, gave 2.0436 grm. MgO. 47.622 per cent. 



27.8286 " 13.2539 " 47.627 



14.6192 " 6.9692 " 47.672 



18.3085 " 8.7237 " 47.648 



Mean. 47.642, ± .0077 



In a supplementary paper ' by Scheerer, it was shown that an impor- 

 tant correction to the foregoing data had been overlooked. Scheerer. re- 



1 .\nn. Chem. Pharni., 110, 240. 



