CHEMISTRY. 363 



Austria, the need of further Hght upon the highly interesting and 

 pressing problems which it suggests was imperative. Therefore, with 

 the help of Mr. Charles Wadsworth, 3d, this work has been continued 

 in the laboratory this year. New specimens of radioactive lead, sent 

 by the kindness of Professor Charles L. Parsons, of Washington, D. C, 

 Mr. S. Radcliff, of Australia, and Dr. Ellen Gleditsch, of Kristiania, 

 have been carefully studied in the manner already described, and, 

 although the investigation is not quite ripe for definite publication, it 

 is far enough advanced to confirm in every respect the earlier work. 

 Particularly the Australian radioactive lead was found to have a very 

 low atomic weight, at least as low as the lead from North Carolina 

 uraninite, and no impurity was detected in its ultra-violet spectrum, in 

 amount capable of producing anything like this effect. Evidently, 

 then, an impurity very similar to lead must exist in radioactive lead; 

 and this impurity can not be separated from it by a moderate number 

 of crystallizations, first of the nitrate and then of the chloride. That 

 some other property of this admixture besides the atomic weight must 

 be different from that of pure lead one can hardly doubt, and the many 

 chemical and physical properties of the AustraUan lead are, therefore, 

 under investigation. During the coming winter every effort will be made 

 to effect the separation and identification of the admixed element. More 

 material than that heretofore available is necessary to solve the problem. 



2. Causes of Inclusion in the Silver Voltameter. 



This investigation also is a continuation of the work on this sub- 

 ject carried out last year. During the present winter the work was in 

 charge of Mr. Norris Folger Hall, who obtained many interesting 

 results on varying inclusion, showing that a number of circumstances 

 tend to affect this quantity and, therefore, the weight of the gentlj'^ 

 heated silver deposited in the silver coulometer. In general, condi- 

 tions were found which made possible the inclusion of distinctly less 

 mother liquor than that found during the previous winter, with the 

 help of Dr. Frederick 0. Anderegg, but the results point to the same 

 conclusion as before, namely, that the amount of inclusion should be 

 determined before one can be sure of the true weight of the precipi- 

 tate. The details of this investigation also are not quite ready for 

 pubheation; and, like the preceding, it will be continued during the 

 coming academic year. 



3. The Standardization of the Thermometric Scale. 



During the preceding winter, by means of a thermochemical method, 

 a new method of standardizing or subdividing the thermometric scale 

 was devised. It consisted in carrying out a mild physico-chemical 

 reaction again and again, each time beginning the reaction (which 

 evolved enough heat to raise the reacting system about 0.2°) at the 

 final temperature of the previous trial. Knowing the change of heat 



