452 Scientific Intelligence. 



their second decimal places, by these changes, and a recalculation 

 of the atomic weights will be necessary soon. Richards suggests, 

 however, that this systematic recalculation be delayed until a few 

 other new data should have been obtained — in particular, new 

 analyses of potassium chloride, silver chlorate, the bromides, sul- 

 phides and sulphates, and similar important compounds. Some 

 of these are already being made, and others will be undertaken 

 at once by Professor Richards. — Carnegie Institution of Wash- 

 ington. Publication ~No. 28. h. l. w. 



3. The Origin of Radium. — A continuation of the investiga- 

 tions of Dr. B. B. Boltwood upon the relative quantities of 

 uranium and radium in various minerals, an account of which 

 appeared in the preceding volume of this Journal, shows that 

 these quantities are proportional to one another, within the limits 

 of experimental errors, even in minerals containing much thorium 

 and very small amounts of uranium. The more recent experi- 

 ments were the examination of twenty-two specimens of min- 

 erals where the accurately determined percentages of uranium 

 vary from 74 to 0*3 per cent, and in this series allowance is made 

 for the emanation lost at ordinary temperatures by the various 

 samples. The author says that the inevitable and only possible 

 conclusion from the results is that uranium is the parent of 

 radium, and that the participation of thorium in the production 

 of radium, which has been suggested by some, is entirely excluded. 

 He also mentions experiments made to determine whether radium 

 is formed directly from uranium. These showed no evidence of 

 this change after a period of seven months and confirm the 

 results of similar experiments by Soddy, so that it is probable, 

 as suggested by Rutherford, that one or more intermediate 

 changes exist between the uranium atom and the radium atom. 

 Attention is called to the persistent appearance of lead as a con- 

 stituent of uranium-radium minerals as an indication that this 

 metal may be one of the final products of the disintegration of 

 uranium. — Phil. Mag. (6), ix, 599. h. l. w. 



4. Marceli Nencki, Opera Omnia — Gesammelte Arbeiten von 

 Prof. M. Nencki— Erster Band, 1869-1885; Zweiter Band, 1886- 

 1901. Large 8vo, pp. xliii + 840, and xiii + 893. Braunschweig, 

 1905. (Friedrich Vieweg und Sohn.) — These two sumptuous vol- 

 umes, edited by N. Sieber and J. Zaleski, contain a fine portrait 

 of Nencki as a frontispiece, a sketch of his life, a complete col- 

 lection of his scientific writings, as well as numerous articles by 

 pupils working under his direction. The work is an important 

 and useful one, because Nencki's publications are scattered 

 through many different journals, and because of the scientific 

 value of his researches. Nencki's work covers a wide field, and 

 the articles have been systematically indexed by the editors. 

 There are many important investigations in pure chemistry — it 

 is said that he took pride in having made over one thousand ele- 

 mentary analyses — but it is well known that his most important 

 work was in the lines of physiological and medical chemistry, and 



