66 Scientific Intelligence. 



the decay of its induced activity, which showed a period of 11*2 

 hours for the half value, while Rutherford has given about 11 

 hours as the characteristic period for the induced activity pro- 

 duced by the thorium emanation. It may be considered certain, 

 therefore, that the substance obtained by Hahn gives off the 

 thorium emanation; but, since comparative tests showed that the 

 product possesses a power of emanation about 250,000 times 

 greater than thorium, it is concluded that it contains a new radio- 

 active element which produces the thorium emanation. The 

 question arises whether two distinct elements may produce the 

 same emanation, or whether the activity of thorium may be due 

 to a mixture with this new element — a question which has not yet 

 been decided. — Perichte, xxxviii, 1756. h. l. w. 



3. The Use of Quartz Apparatus for Laboratory Purposes. — 

 Mylius and Meusser of the Phys.-Techn. Reichsanstalt at Char- 

 lottenburg have investigated the action of various liquids upon 

 quartz vessels by finding the loss in weight after such action. 

 They find that water has no appreciable effect either at ordinary 

 temperature or at 100°. In fact, the electrical conductivity of 

 water may be diminished by boiling off the carbonic acid in these 

 vessels. The vessels are attacked by alkaline liquids, and in this 

 respect they appear to possess no advantage over glass. Dilute 

 acids, with the exception of hydrofluoric, and concentrated sul- 

 phuric acid have no appreciable action at 100°, or at lower tem- 

 peratures. Corrosion is produced by phosphoric acid when it is 

 concentrated above 400°, and white silicylphosphate separates. 

 Quartz vessels possess the property of absorbing certain dyes 

 from their solutions. The amounts thus absorbed are exceed- 

 ingly small, forming a uniformly colored film when the vessels 

 are rinsed, and this can be removed by the use of hot solvents. — 

 Zeitschr. Anorgan. Chem,, xliv, 221. h. l. w. 



4. Permeability of Quartz Vessels to Gases. — It has been 

 observed that vessels of quartz glass are permeable to helium at 

 temperatures below red heat, and Berthelot has recently found 

 that other gases, for instance, atmospheric nitrogen, are capable 

 of penetrating tubes of this material at a temperature of about 

 1,300°. This property of fused quartz will somewhat limit its 

 applications for investigations at high temperatures. — Comptes 

 Mendus, cxl, 821. h. l. w. 



5. Outlines of Inorganic Chemistry ; by Frank Austin 

 Gooch and Claude Frederic Walker. 12mo, pp. xxiv + 233 

 -t-514. New York, 1905 (The Macmillan Company). — This text- 

 book of elementary chemistry, a large and comprehensive work, 

 is divided into two distinct parts, " inductive " and "descriptive." 

 About twice as many pages are devoted to the latter part as to 

 the former. It has been the aim of the authors to introduce the 

 student to chemistry by consideration of the simplest and fewest 

 things, and much attention has been paid to the inferences to be 

 drawn from experimental phenomena. Part I takes up the con- 

 secutive experimental development of the principles upon which 



