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CARNEGIE INSTITUTION OF WASHINGTON. 



This work should be continued and pursued in several different 

 directions. The effect of temperature and pressure upon the course 

 of the various reactions should be carefully studied, as also the effect 

 of the nature of the solvent used. It is only by an elaborate study, 

 such as I have planned, that anything like a clear view regarding the 

 relation between the two tautomeric chlorides can possibly be gained. 



Richards, Theodore W., Harvard University, Cambridge, Massachusetts. 

 Continuation of exact investigation of atomic weights and other 'physico- 

 chemical properties of elements and simple compounds. (For previous 

 reports see Year Books Nos. 2-15.) 



Although various causes contributed to diminish the amount of 

 experimental work, several results of importance were obtained. The 

 following investigations have been conducted during the past academic 

 year with the assistance of this grant, employing permanent apparatus 

 purchased with previous grants as well as with funds of the university. 



Atomic weight of ordinary lead. 



1. Attempt to Separate the Isotopic Forms of Lead by Fractional Crystallization. 



This research, which was a logical outcome of the earlier researches 

 on the nature of radioactive lead, was partly carried out during the 

 summer with the help of Dr. Norris F. Hall. Lead from Australian 

 carnotite (believed to contain about 1 part of ordinaiy lead to 3 parts 

 of radium G, with a mere trace of radium D) was fractionally crystal- 

 lized over 1,000 times as nitrate and the end-fractions were purified 



