260 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE 



I. Chemistry and Physios. 



1. New Method of Forming Liquid Alloys of Sodium and 

 Potassium. — It has been found by Jaubert that when metallic 

 sodium acts upon potassium hydroxide, or when metallic potas- 

 sium acts upon sodium hydroxide, there are formed in both 

 cases, at a slightly elevated temperature, liquid alloys of the 

 two alkali metals containing up to nearly 80 per cent of 

 potassium. The very remarkable circumstance that both of 

 these reactions take place and both give practically the same 

 product appears to be due to the fact that these alkali metals 

 combine to form the compounds NaK and NaK 2 with the libera- 

 tion of a considerable amount of heat. The following equations 

 represent the reactions : 



K, + NaOH = KOH + NaK,, 

 Na 3 + 2KOH = 2NaOH + Nal 

 Na„ + KOH = NaOH + NaK. 



These reactions give almost quantitative yields, and they are 

 brought about by heating the reacting substances to from 225° 

 to 350° in the different cases. The operation may be carried 

 out either under paraffine or in an exhausted vessel. The 

 reaction corresponding to the second of the equations given 

 above is one by means of which an alloy rich in metallic potas- 

 sium is now being made cheaply on a commercial scale in 

 France, and the product promises to have important industrial 

 applications, since, as is well known, potassium in many cases 

 gives reactions entirely different from those of sodium, and it often 

 reacts where sodium is without action. In connection with 

 these results the author points out the falsity of the statement, 

 given in most works on chemistry, that the alkali metals react 

 with their hydroxides to form their oxides ; for example, 



Na + NaOH = Na 2 + H, 



and that only the opposite reaction, 



Na 2 + H =: NaOH + Na, 



is possible, as has been shown by Becketoff. — Bulletin, IV, iii, 

 1126. h. l. w. 



2. The Determination of Cerium and other Rare Earths in 

 Rocks. — It has been found by Dietrich that when oxalic acid 

 or ammonium oxalate is added to a cerium solution in the pres- 

 ence of ferrous sulphate, cerium oxalate is precipitated, but this 

 precipitate contains a considerable amount of iron when a large 

 quantity of this metal is present. When a neutral solution of a 

 ferric salt is present no precipitate of cerium oxalate is produced 



