CHEMISTRY — BASKKRVTLLE, BAXTER. 147 



The results of the two analyses, using different methods, are as follows : 



If the anh3^drous salt be taken as a basis for the calculation, we find the 

 following figures, agreeing closely : 



ThO^ 

 SO3. 



Calculated for 

 ThOSOi. 



Per cent. 

 76.74 

 (23.26) 



Found. 



Per cent. 



76.84 



(23.16) 



Since, in this particular instance, we failed to obtain the octo- or ennea- 

 hydrate, preparing instead a substance heretofore unknown, we have begun 

 a series of determinations with a sample of octohydrate. 



In conclusion it may be remarked that, whereas the equilibria of the 

 various hydrates of thorium sulphate between 0° and 100° C. have been 

 made the subject of an extensive study by Roozeboom, there are no data at 

 hand concerning the decomposition curves of the tetrahydrate and of the 

 anhydride at temperatures above 100° C. For an exact revision of the 

 atomic weight of thorium these data will be now indispensable. 



Baxter, Gregoty P*, Harvard University, Cambridge, Massachusetts. Grant 



No. 293. Researches upon ato7nic zveights, particularly of manganese. 



(For previous reports see Year Book No. 3, p. 105, and Year Book No. 4, 



pp. 149-150.) $1,000. 



Five investigations have been carried on by Professor Baxter or under his 



direction. 



(i) With Dr. Murray A. Hines the investigation upon the atomic weight 

 of manganese, begun with Grant 154 (see Year Book No. 4, p. 149, 1905) 

 by analysis of manganous bromide, was continued by the analysis of man- 

 ganous chloride. This salt was prepared for analysis by fusion in a current 

 of hydrochloric acid gas which had been dried with sulphuric acid. Then, 

 after solution in water, the chloride was titrated against a weighed equiv- 

 alent amount of the purest .silver. Finally the precipitate of silver chloride 

 was collected and weighed. The result for the atomic weight of manganese 

 obtained from the analysis of manganous chloride is essentially identical 

 with that previously found by analysis of manganous bromide, the final 



