80 Scientific Intelligence. 



connection with the theory of the production of radium by ura- 

 nium. Other investigators have concluded that this ratio is 

 practically constant, but she has obtained the following results 

 after making corrections for certain sources of error in her method: 



Radium : Uranium 



French autunite, __.__ 2*85 X 10~ 7 



Joachimsthal pitchblende, 3-58 X 10 -7 



Ceylon thorianite, 4-] 9 X 10 -7 



While these results show magnitudes of the same order, they do 

 not agree closely, and the author concludes that the determina- 

 tion of the mean life of radium based upon the existence of a 

 constant ratio between the uranium and radium in minerals can- 

 not be considered exact. 



It may be observed in regard to this conclusion that the author 

 does not appear to take into consideration the possible removal 

 by solution of a part of the radium from the minerals, h. l. w. 



4. The Action of Radium Emanation upon the Elements of 

 the Carbon Group. — Ramsay and Usher, using the emanation 

 produced in about a week from 1*21] lg. of metallic radium, have 

 caused this to act upon solutions of silicon, titanium, zirconium, 

 thorium, and lead compounds for periods of about four weeks, 

 with the result that they believe that they have proven the pro- 

 duction of carbon by this action. The following table shows the 

 amounts of carbon found per cubic millimeter of emanation : 



Solution of Carbon, mg. 

 H 2 SiF 6 0-518 



Ti(S0 4 ) 2 0-982 



Z ^ s ° 4 ) 2 jn ::::::::;:;:;;:;;;;::;:;:; o-8?3 

 Th ( N °3) 4 ]n ;;;;;;;■;;;;;;;;;;;;;;;;; 0^8 



Pb(C10 3 ) 2 0-102 



r p 



The carbon was found in the form of the dioxide, or as a mixture 

 of this with the monoxide. The amount of C0 2 measured amounted 

 in one case to more than 0*5 CC . The authors state that mercurous 

 nitrate gave no trace of carbon dioxide or monoxide, and that 

 similar experiments are being performed with the compounds of 

 other elements. 



It is probable that the statement in regard to this production 

 of carbon from other elements will be received with much 

 incredulity, because Sir William Ramsay's previous assertion of 

 the production of lithium from copper in a similar manner was 

 not confirmed. — Berichte, xlii, 2930. h. l. w. 



5. Quantitative Chemical Analysis ; by Clowes and Coleman. 

 8vo, pp. 5^4. Philadelphia, 1909 (P. Blakiston's Son & Co.). — 

 This English book, which is also issued in America, has passed 

 through eight editions, with continual improvement and enlarge- 

 ment, since its first appearance in *1891. It gives an introduction 



