

Broioning and Spencer — Separation of CcBsium, etc. 281 



This method was applied quite successfully to the extraction 

 of caesium from pollucite as follows : 



The mineral was decomposed by hydrochloric acid, and after 

 evaporation and the removal of silica the acid extract was poured 

 upon crystals of ammonium aluminium alum and warmed until 

 the crystals had dissolved. On cooling, caesium alum separated 

 in abundance; and the mother liquor, although not free from 

 caesium, after one treatment consisted mainly of ammonium 

 chloride. After about two recrystallizations the crystals 

 obtained in the first treatment were found to give no test for 

 either ammonium or chlorine and to be pure caesium alum. 

 The remainder of the caesium was easily obtained by a few 

 crystallizations of the mother liquor. 



This method has advantages over the other methods for the 

 extraction of caesium from pollucite which involve the pre- 

 cipitation of the caesium as the double lead or antimony chlo- 

 ride and the decomposition of these compositions by hydrogen 

 sulphide or ammonium hydroxide. 



A few experiments were made to determine the insolubility 

 of the caesium and rubidium in a saturated solu.tion of ammo- 

 nium aluminium alum. It was found that 1 cm 3 of a solution 

 of RbCl containing 0-0002 grams Rb would give a perceptible 

 precipitate when treated with 5 cm 3 of a saturated solution of 

 ammonium alum, and that 1cm 3 of a solution of CsCl contain- 

 ing - 00005 grams Cs would give a precipitate of caesium alum. 



By the careful study of conditions and the use of the other 

 alums it is hoped that these observations may lead to some 

 advances in the analytical study of these elements, and we hope 

 to give further attention to this problem. 



SCIENTIFIC INTELLIGENCE. 



I. Miscellaneous Scientific Intelligence. 



1. The Collection of Osteological Material from Machu 

 Picchu ; by George F. Eaton. Memoirs of the Connecticut 

 Academy of Arts and Sciences, vol. V, pp. 1-96, figs. 50, plates 39, 

 charts 3. New Haven, Conn., 1916. — The monograph in hand is 

 a creditable and well-illustrated report on the collection of 

 osteological material gathered from Indian graves at Machu 

 Picchu by the Peruvian Expedition of 1912, under the leadership 

 of Professor Hiram Bingham, and the auspices of Yale University 

 and the National Geographic Society. 



The remains described were obtained from graves " found at 

 various places on the steep sides of the Machu Picchu mountain, 



