92 Scientific Intelligence. 



weight of radium. Thorpe states that the chloride gradual^ 

 increases in weight when exposed to the air, apparently on 

 account of oxidation by ozone, the presence of which can be per- 

 ceived by the odor, and by other tests. Another peculiarity of 

 the radium salt is its action upon the vessels containing the 

 solution. It gradually changes the color of colorless rock crystal 

 vessels to deep purplish black, and these as well as porcelain and 

 glass vessels appear to be slightly attacked chemically with 

 the formation of silicates. — Chem. News, xcvii, 229. h. l. w. 



3. The Poli/iodides of Potassium, Rubidium, and Caesium. — 

 Using solubility methods, together with analyses of the undis- 

 solved residues, Foote and Chalker have determined the poly- 

 iodides of potassium, rubidium, and caesium existing at 25°, and 

 have found positive evidence of the existence of KI 3 , KI 7 , Rbl 3 , 

 Csl 3 , and Csl 5 , while they found no evidence whatever of the 

 existence of Rbl 7 , Rbl 9 , Csl 7 and Csl 9 which had been supposed 

 to exist by Abegg and Hamburger, who used somewhat similar 

 physical methods, but did not analyze the residues. It is to be 

 noticed, also, that Abegg and Hamburger did not find KI 3 , the first 

 of these compounds that was discovered. It appears that while 

 Abegg and Hamburger's work was correct in principle, there 

 must have been some irregularity in their solubility determina- 

 tions, leading to incorrect conclusions. — Amer. Chem. Jour., 

 xxxix, 561. h. L. w. 



4. A Volumetric Method for Copper. — A process based upon 

 the titration of cuprous thiocyanate with potassium iodate solu- 

 tion in the presence of strong hydrochloric acid has been worked 

 out by Jamieson and others of the Sheffield Scientific School. 

 The reaction corresponds to the equation 4CuSCN + 7KI0 3 -f- 

 14HCI = 4CuS0 4 + 7KCl + 7lCl + 4HCN + 5H 2 0. The titration is 

 carried out in a glass-stoppered bottle with a liquid containing 

 about half of its volume of concentrated hydrochloric acid in the 

 presence of a little chloroform. The disappearance of the iodine 

 color in the chloroform marks the end of the reaction, and it 

 is exceedingly sharp and delicate. The presence of filter paper 

 does not affect the result. This general method of titration is 

 due to L. W. Andrews, but it was not applied by him to thiocy- 

 anates, to which it has now been found to be applicable. The 

 authors give details for applying the method to copper ores and 

 alloys in such a way as to remove interfering substances. Test 

 analyses showed excellent results, and the method appears to be 

 a very rapid and accurate one. — Jour. Amer. Chem. Soc, xxx, 

 760. " h. l. w. 



5. Thermodynamics of Technical Gas- Reactions; by F. Haber. 

 Translated by Arthur B. Lamb. 8vo, pp. 356. London and New 

 York, 1908 (Longmans, Green & Co.). — This book consists of a 

 series of seven lectures which have been considerably enlarged 

 for publication. The mechanical theory of heat is developed, as the 

 author says, from its very foundations. Then a number of reactions, 

 which are important industrially, are treated from a theoret- 



