On Chemical Analysis by Specirum-observatioM. 499 



of the anhydrous salt in the form of a sandy friable white mass, 

 which rapidly absorbs moisture from the air. At a red heat the 

 anhydrous salt melts ; and it may be heated to whiteness, at which 

 temperature it begins to volatilize, without losing carbonic acid. 

 Placed on a platinum wire in the flame, it soon volatilizes com- 

 pletely. The aqueous solution of the salt possesses a strong 

 alkaline reaction and taste ; when rubbed between the fingers, it 

 produces the peculiar soapy feeling characteristic of the alkalies, 

 and it acts as a cautery when it is allowed to remain for some time 

 in contact with the skin. Water containing 10 Q 0Q th part of 

 the salt turns red litmus-paper distinctly blue. 



Monocarbonate of caesium possesses a property which is re- 

 markable in the alkaline carbonates, that, namely, of solubility 

 in absolute alcohol. 100 parts of alcohol dissolve, at 19° C, 

 ll'l, and at the boiling-point of the alcohol 20*1 parts of this 

 salt. The carbonate can be obtained in the form of small irre- 

 gular crystals by quickly cooling the alcoholic solution. If the 

 cooling be carried on slowly to temperatures below 0° C, the 

 salt sometimes separates out in tabular crystals often 1 inch in 

 length, especially if some quantity of caustic oxide of caesium be 

 present. 0*7921 grm. of the fused salt lost, on treatment with 

 dilute sulphuric acid, 0-1120 grm. carbonic acid. Hence the 

 salt contains — Calculated. Found. 



CsO . . . 131-35 85-65 85-86 



CO 2 . . . 22-00 14-35 14-14 



153-35 100-00 100-00 



d. Bicarbonate of Ccesium. 

 A solution of monocarbonate of caesium, exposed in an atmo- 

 sphere of carbonic acid, passes into this salt in the course of a 

 few days. The solution, on standing in the air at the ordinary 

 temperature over sulphuric acid, deposits large but indistinctly 

 formed striated crystals, which are unalterable in the air, and 

 assume a prismatic form ; they possess a feeble alkaline reaction ; 

 their aqueous solution gives off carbonic acid on boiling, and in 

 outward properties they cannot be distinguished from the cry- 

 stals of the corresponding rubidium salt. 0'8155 grm. of fused 

 monocarbonate of caesium yielded - 976l grm. of bicarbonate 

 when exposed for some days in an atmosphere of carbonic acid, 

 and afterwards dried over sulphuric acid. Hence the composition 



of the salt is- 



CsO . . . 131-35 71-25 7156 



2C0 2 . . . 44-00 23-87 



HO. . . . 9-00 4 



Calculated. Found. 



71-56 



28-44 



•87| 

 •88J 



184-35 100-00 100-00 



