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IX. Chemical Notices from Foreign Journals. By E. Atkinson, 

 Ph.D., F.C.S., Teacher of Physical Science in Cheltenham 

 College. 



[Continued from vol. xxi. p. 504.J 



IN the investigation of the new metal caesium (Cs), which stands 

 nearest potassium, Bunsen* has found that, besides csesium, 

 there exist sanother metal previously unknown, and which seems 

 to resemble potassium as closely as does csesium. 



The platinum salt of caesium is more difficultly soluble in water 

 than that of potassium. On trying to separate the latter from 

 the former by repeated boilings with water, in proportion as the 

 quantity of potassium decreases, the continuous potassium spec- 

 trum between Ka and K/3 becomes fainter, and new lines appear, 

 more especially two very intense ones in the violet between SrS 

 and K/3. A limit is soon reached at which the quantity of potas- 

 sium cannot be further diminished. This is the case when the 

 sum of the atomic weights of the metals, combined with platinum 

 and chlorine, has reached 109 (H = l). If from the platinum 

 compound thus obtained the mixture of the hydrated oxides of 

 potassium and caesium is prepared, and if about the fifth part of 

 this is converted into carbonate, absolute alcohol will extract 

 from the dried mixture of the salts principally the hydrated 

 oxide of caesium. If this operation be repeated, a limit is ulti- 

 mately attained at which the part dissolved in alcohol has a 

 constant composition. This limit is reached when the atomic 

 weight has risen from 109 to 123*4. The substance which has 

 this enormous weight (next to gold and iodine the highest 

 known) forms a deliquescent hydrate, as caustic as hydrate of 

 potass. It also forms a deliquescent, strongly alkaline car- 

 bonate, of which about 10 parts are soluble in 100 parts of abso- 

 lute alcohol at the ordinary temperature, and an anhydrous 

 nitrate, which, unlike nitre, is not rhombic but is hexagonal, 

 and by a hemihedral form is isomorphous with nitrate of soda, 

 &c. The spectrum of the substances purified up to the atomic 

 weight 123*4, shows the blue caesium lines in the most brilliant 

 lustre, but the violet lines of the unpurified mixture (of the 

 atomic weight 109) in so feeble a degree, that a small addition 

 of chloride of potassium, which is almost without perceptible 

 action on the lines Csa, causes them entirely to disappear in 

 consequence of the brightness of the ground produced by potas- 

 sium. The material for this investigation, only amounting to a 

 few grammes, was prepared from 44,000 kilogrammes of Diirck- 

 heim mineral water. On repeating the preparation from 



* Bericht der Akad. der Wissenschaften zu Berlin, 1861. 



