460 Scientific Intelligence. 



5. Separation of Antimony and Tin. — A new method for 

 this somewhat difficult separation is given by A. Czeewek. It 

 depends upon obtaining a solution in nitric and tartaric acids, 

 heating to boiling and adding phosphoric acid, whereby the tin 

 is completely precipitated. The precipitate, after being washed 

 with water containing ammonium nitrate, is dissolved in ammo- 

 nium sulphide, and the tin is precipitated and determined in the 

 usual manner. The antimony and other metals that the filtrate 

 may contain must also be precipitated as sulphides in order to 

 separate them from the phosphoric acid present. Satisfactory 

 results are given in a number of test analyses. — Zeitschr. Analyt. 

 Chem., xlv, 505. H. l. w. 



6. Lehrbuch der Allgemeinen Chemie ; by Dr. W. Ostwald. 

 Volume II, Part III. — The third part of Volume II of the Lehr- 

 buch has appeared in sections, and we have just received the first 

 part of the second section. The book is so divided into volumes 

 and parts and sections that it is a little confusing in this respect. 

 The work is so well known to students of general chemistry that 

 it is unnecessary to speak of it as a whole. The part which has 

 just been issued covers solid solutions more fully than this has 

 been done before and begins the chapter on adsorption. 



h. w. F. 



7. Radio- activity. — The literature of this subject increases 

 very rapidly. Apart from the numerous observations on the 

 various forms of radio-active substances and their multifarious 

 manifestations, there are certain aspects of radio-activity which 

 have a broad bearing upon the constitution of the sun and the 

 radio-active constitution of this earth and its atmosphere. A 

 recent paper on the radio-activity of the ashes and lava thrown 

 up by the late eruption of Vesuvius (August Becker, Ann. der 

 Physik, No. 8, 1906) is of much interest. Since it has been 

 shown by various observers that radio-activity is widely present 

 in the earth's crust, the question has arisen, whether it would not 

 be possible to connect the phenomena of radio-activity with the 

 earth's temperature ? Under the assumption of a mean value of 

 0*006 for the heat conduction of the earth's crust, and a tem- 

 perature fall of 1° C. for 30 meters, Liebenow estimates the 

 quantity of radium per cubic meter evenly distributed, which 

 would give the observed heat as approximately 2Xl0 _7 g. Since 

 the quantity of radium observed is 1000 times this, we must con- 

 clude that the heat production diminishes rapidly as we recede 

 from the crust and that at great depths there cannot be radio- 

 active substances. Strutt corroborates the results of Liebe- 

 now and concludes that at a depth of 75 km radio-activity fails. 

 Becker, therefore, submitted to test the ashes and lava of the 

 eruption of Vesuvius, and corroborates in general the observa- 

 tions and conclusions of Strutt, pointing out, however, that 

 we are unable to estimate conditions of pressure and tempera- 

 ture at the. depth from which the lava and ashes came, presum- 

 ably 30 km . 



