142 Scien tific In t'dUgt nee. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistet and Physics. 



1. The Separation of Yttrium from the Yttrium Earths. — 

 Professor James and his co-workers have tried many reagents in 

 order to discover the most suitable ones for the separation of cer- 

 tain rare earths from each other. In a recent article J. B. 

 Bonardi and C. James have described a continued search for a 

 rapid, efficient and economical method for the separation of 

 yttrium from the accompanying yttrium earths. The process 

 used in each case was the fractional precipitation of the mixture 

 by means of successive additions of the reagent. The extent of 

 the separation was then ascertained, usually by making atomic 

 weight determinations upon the earths obtained in the succeeding 

 fractions, but in some instances the unchanged color of the earths 

 gave sufficient indication of unsatisfactory separation. The 

 reagents tried were ammonium sebacate, azobenzene sulphonic 

 acid, potassium sulphite, sodium citrate, sodium tungstate, sodium 

 tartrate, sodium ^-nitrobenzoate, ammonium camphorate, sodium 

 phenoxacetate, and potassium cobalticyanide. The last reagent 

 mentioned gave the most promising results. The neutral solution 

 of the chlorides was heated to boiling and stirred while a solu- 

 tion of potassium cobalticyanide was slowly added. The pre- 

 cipitates were white and granular and filtered easily. Five 

 fractions obtained from a mixture of earths in this way gave the 

 following results: 



12 3 4 5 



Atomic weight 98-7 95"1 90'8 88-2 905 



Weight of fraction ll'9g. 11'8 g. 10-4g. 4*1 g, 0-7g. 



Fraction 5, which was precipitated with oxalic acid after four 

 previous precipitations with the cobalticyanide, showed an unex- 

 pectedly high atomic weight, but it was found to be contami- 

 nated with neodymium, a rare earth metal of high atomic weight, 

 belonging to another group. This fraction and fraction 4 showed 

 an entire absence of the erbium bands in the absorption spec- 

 trum. The oxides of these two fractions were white, while frac- 

 tion 1 gave oxides of a decidedly pink tint. The authors 

 consider this method for the preparation of pure yttrium one of 

 the most rapid that they know, and they propose to carry on 

 further investigations soon with this very interesting reagent. — 

 Jour. Amer. Chem. Soc, xxxvii, 2G42. B. l w. 



2. A Volumetric Method for Potassium. — G. Ajon has pro- 

 posed the following method for application to fertilizers, and 

 states that it yields accurate results. Put into an Erlenmeyer 

 flask 25 cc of a 2 per cent KC1 or K 2 S0 4 solution, add slowly 

 while agitating 50 cc of 2 N~ tartaric acid and then 25 ec of 0-5 N 

 NaOH solution. Shake for 5 min. with a rotary motion, then 



