Chemistry and Physics. 91 



SCIENTIFIC INTELLIGENCE 



I. Chemistry and Physics. 



1. The Atomic Weight of Lead from Ceylon Thorite. — F. 

 Soddy and H. Hyhan have carried out a preliminary atomic 

 weight determination upon the lead extracted from Ceylon thorite. 

 The authors found in this mineral 54*5 per cent of thorium, 0*35 

 per cent of lead, and 0*72 or 1*6 per cent of uranium, accord- 

 ing to two methods of determination, the first chemical, the 

 other calculated from the radium present in the mineral. Accord- 

 ing to recent theories of radio-activity a mineral rich in thorium 

 and poor in uranium may contain lead with an appreciably higher 

 atomic weight than ordinary lead, for if the end products of 

 both uranium and thorium are, as is supposed, the isotopes of 

 lead, the former should have an atomic weight of 206, and the 

 latter 208*4, while the accepted value for ordinary lead is 207*1. 

 Rather more than a gram of purified lead chloride was obtained 

 from about a kilogram of the mineral. This was compared with 

 ordinary lead chloride, and titration with silver nitrate solution 

 was the method used. The results indicated that the thorite 

 lead had an atomic weight of 208*4 if the ordinary lead was 

 207*1, while the value calculated from the composition of the 

 mineral, if all the lead in it was derived from the radio-active 

 elements, was 208*2. The authors say that the results so far car- 

 ried out do not settle the question, but show a difference in the 

 expected direction of the right order of magnitude. — Chem. 

 News, cix, 159. h. l. w. 



2. The Extraction of Germanium from the Waters of Vichy. 

 — J. Baedet, by spectroscopic examination, has found a great 

 many heavy metals in mineral waters, and among them gallium 

 and germanium were almost constantly present. Since there are 

 few available sources of germanium, as the deposit of argyrodite 

 at Freiberg is exhausted, and as the extraction of this metal 



from the blendes in which it was discovered by LYbain is a long 

 and expensive operation, Bardet has undertaken the experiment 

 of extracting germanium from the residues of the evaporation of 

 mineral waters. It was found that in the manufacture of Vichy 

 salts from the natural waters the first heating of the water causes 

 the decomposition of the bicarbonates and the precipitation of 

 the alkali-earth carbonates, and that this precipitate, which is 

 chiefly calcium carbonate, contains the greater part of the heavy 

 metals, including the germanium. From about 100 kg. of this 

 precipitate pure germanium oxide weighing 060 g. was extracted 

 by a comparatively simple process. It was calculated that this 

 represented some 250,000 liters of the original Vichy water, and 

 corresponded to T -o| ; Vo o - m -S- °^ germanium oxide per liter. This 

 estimate is a minimum on account of losses during extraction 



