Chemistry and Physics. 469 



Blakiston's Son <fe Co.). — The present edition of this valuable 

 treatise on electrolytic analysis shows but few changes from the 

 previous edition, which appeared about four years ago, but the 

 essentials of all that has appeared upon the subject during the 

 interval have been added. The book shows in an impressive way 

 the great advances that have been made in this comparatively 

 recent branch of analytical chemistry, and the large number of 

 determinations and separations that can be conveniently and accu- 

 rately made in this manner. h. l. w. 



8. The Disintegration Products of Uranium. — It is now 

 generally accepted that uranium is the primary substance from 

 which ionium and radium with its series of products are derived. 

 In old minerals all a-ray products in radio-active equilibrium with 

 uranium emit an equal number of a-particles per second except 

 uranium itself, which emits twice as many. Consequently either 

 two a-particles are emitted at the disintegration of each atom, or 

 the uranium is in equilibrium with an unseparated a-ray product. 

 Furthermore, it is known that uranium-X is a direct product of 

 uranium, but at present no definite transformation product of the 

 former has been obtained. Also, some irregularities in the 

 behavior of uranium-X have been noted by several investigators. 



An important advance towards the solution of the general 

 problems just suggested has been made by G. N. Antonoff. 

 This investigator has established the existence of a new radio- 

 active product which he symbolizes by " Ur Y." 



In referring to the work of his predecessors, Antonoff says : — 

 " In all these investigations no evidence of the purity of the 

 uranium preparations has been given." Therefore, the first step 

 in the present investigation was to make preparations of uranium 

 from which all known radio-active impurities had been separated. 

 Special tests afforded definite proof that this condition had been 

 attained. For details of the chemical processes involved in the 

 purification of the uranium salts reference must be made to the 

 original paper. It should be stated, however, that two methods 

 were employed in the separation of uranium-X. The first method 

 consisted in precipitating barium in the uranium solution as 

 barium sulphate, and the second in adding an iron salt to the 

 uranium solution and precipitating it by boiling. 



It is known that uranium-X emits both "soft" and "hard" /3- 

 rays. The activities of the uranium-X preparations were deter- 

 mined first with the salts uncovered and afterwards when 

 aluminium foil 0-01 om thick was placed over the radio-active 

 material. The first measurement gave the total activity, and the 

 second the activity due to the hard rays. Uranium-X separated 

 from uranium by the barium method gave exponential decay 

 curves with practically identical periods for both types of rays. 

 Also the absorption curves of such preparations taken at different 

 intervals of time after separation are always of the same shape, 

 indicating that the uranium-X contains no other active product. 



On the other hand, when uranium-X is separated by the ferric 

 method, a rapid initial drop in the decay curve was always 



