448 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. The chemistry of the Cyanide Process. — Two views have 

 been expressed concerning the chemical reaction which takes 

 place in this very important, recent process for extracting gold 

 from its ores. These are represented by the following equations : 



2Au + 4KCN + 2H,0 = 2KAu(CN)^ + 2KOH + H^ 

 4 Au + 8KCN + 2Hp + O, = 4K Au(CN), + 4K0H 



The second equation represents the view which is now gener- 

 ally accepted, and Bodla^ender has recently shown conclusively 

 that no hydrogen is evolved when gold is placed in contact with 

 potassium cyanide solution. He placed finely divided gold and 

 the cyanide solution in an exhausted retort, and after a contact 

 of fourteen days no hydrogen could be detected, He showed, 

 moreover, that the presence of oxygen was necessary for the dis- 

 solution of the gold, but he has found that the commonly accepted 

 equation, the second one given above, does not fully represent 

 the reaction, but that hydrogen peroxide is at first produced and 

 that the reaction takes place in two stages, viz., 



2Au + 4KCjSr + 2H,04-0., = 2KAu(Crsr), + 2KOH4-H,0, 

 2 Au + 4KCN + H^O, = 2KAu(CN)., + 2K0H 



The author proved conclusively that hydrogen peroxide is pro- 

 duced in the reaction, and that its formation is more abundant 

 the moi-e rapidly the solution of the gold takes place. When the 

 hydrogen peroxide was removed as fast as it was formed by hav- 

 ing calcium hydroxide present in the solution (thus producing a 

 precipitate of calcium peroxide), the author was able to obtain 

 about two-thirds of the theoretical hydrogen peroxide by quanti- 

 tative determination. — Zeitschr.fUr angeio. Chem.^ 1896, 583. 



H. L. W. 



2. JBeryllium not isomorphous with the fnetals of the ynagne- 

 sium group. — The true place of beryllium in its relation to other 

 elements has been a matter of much discussion. It is at present 

 generally admitted that it is a bivalent element, and the isomorph- 

 ism of its salts with those of the metals of the magnesium group 

 is assumed by the authors of certain text books, although such 

 isomorphism does not appear to have been distinctly proven. 

 Retgers has now made a careful study of the crystallization of 

 mixtures of beryllium sulphate and the sulphates of copper, nickel, 

 iron and manganese, and has discussed the results ol Klatzo, who 

 used the sulphates of magnesium and zinc in the same way with 

 beryllium sulphate, as well as the results of Marignac and of 

 Atterberg in connection with beryllium and magnesium salts. 

 He finds that there is no evidence of the isomorphism of beryllium 

 with any of these metals. He believes also that the apparent 



