Chemistry and Physics. 431 



dilution with a small amount of water this liquid gave with 

 hydrogen sulphide a white floeculent precipitate. If, however, 

 the distillate was greatly diluted the precipitation was slow and 

 incomplete, but in this case the addition of strong hydrochloric 

 acid caused an immediate precipitation. The white sulphide was 

 soluble in ammonia and in alkaline sulphide solution. Upon 

 ignition the sulphide gave a white oxide. It was found further 

 that the element gave a sparingly soluble double potassium 

 fluoride. These reactions agree with the properties ascribed by 

 "Winkler to germanium. Two portions of the sulphide were col- 

 lected on a Gooch filter, dried at 110° and weighed, then after 

 conversion to oxide by ignition it was found that the ratio 

 Ge0 2 : GeS, was - 749 and 0*744, whereas the theoretical ratio 

 for the atomic weight 72-5 is 0-766. An approximate determina- 

 tion of the Ge0 2 in the material used gave - 25 percent. Several 

 zinc ores were tested for germanium by the chemical method 

 that has been mentioned. Joplin ore and some Mexican ores 

 gave positive tests, but the amounts were very much smaller than 

 that in the Wisconsin material. The Franklin ores gave negative 

 results. A spectroscopic examination of the product by Dr. K. 

 Burns of the U. S. Bureau of Standards indicated that germanium 

 was the principal constituent while zinc was absent, lead weak, 

 silicon present, tin fairly strong, copper present (?), cadmium 

 trace, gallium present and indium trace. This occurrence of 

 germanium is very interesting and it leads to the hope that a 

 practical source of this exceedingly rare element has now been 

 found. — Jour. Indus, and Eng. Chem., viii, 585. h. l. \v. 



2. A New Volumetric Method for Cobalt. — W. D. Engle and 

 R. G. Gustavson have devised a method for the determination 

 of cobalt, which can be applied in the presence of nickel and 

 gives excellent results according to the test analyses of the 

 authors. To apply the method the metals of the copper and iron 

 groups and also manganese are first removed by suitable methods. 

 The solution may contain, besides cobalt, nickel, zinc and the 

 metals of the alkalies and alkaline earths, but must be free from 

 any substance that will liberate iodine from potassium iodide in 

 acid solution. This solution having a volume of about 100 cc is 

 made acid with dilute sulphuric acid, using about 5 CC in excess, 

 and 1 or 2 g. of dry sodium perborate are added. After agitation 

 and solution of the perborate, sodium hydroxide is added to 

 strong alkaline reaction and the mixture is boiled for 10 minutes 

 to decompose the excess of perborate. This operation precipitates 

 cobaltic hydroxide, Co(OH) 3 , while nickel does not form a higher 

 oxide. The solution is now cooled to room temperature and, 

 after 1 g. of potassium iodide has been added, the solution is 

 acidified with dilute sulphuric acid and, after the precipitate has 

 dissolved, the liberated iodine is titrated with standard sodium 

 thiosulphate solution. The theoretical value of this solution, 

 based upon standardization with potassium dichromate, was found 

 to agree very closely with the value obtained by standardizing 



