HYDRATES AND CARBONATES OF THE ALKALI-METALS, ETC. 443 



baryta is not subject to dissociation at the degree of red heat which prevailed in our 

 muffle. To make, however, quite sure of this result, the carbonic acid in the product 

 was determined by the direct method, and the baryta in the residual solution as sulphate. 

 The 2-2149 grm. of product gave 0*4928 of C0 2 , and 2*6182 of BaS0 4 . Hence— 



Found. Calculated from BaC0 3 . 



Carbonic acid, . . . 22-249 22-312 



Baryta, . . . 77-635 77-688 



99-884 100-000 



Carhonate of Lithia. 



This carbonate, as we have seen, is completely reduced to anhydrous oxide, if kept at 

 a red heat in hydrogen for a sufficient time * the last instalments of the carbonic acid, 

 however, go away very slowly, which indicates the existence of a basic carbonate 

 relatively difficultly reducible by hydrogen. The following two 



Nitrogen- Experiments were made with the view of seeing whether, or to what extent, 

 a similar decomposition can be brought about by the action of heat alone. In both the 

 carbonate was heated within a porcelain boat in a muffle as described above. 



In Experiment I, the heating, after attainment of the maximum temperature, was 

 continued for one hour (?). # 



0'6024 grm. of the product gave 0*3303 of C0 2 and 0*9983 of Li 2 S0 4 corresponding 

 to 54*83 per cent, and 45*22 per cent, respectively, or to the following proximate 

 composition : — 



Carbonate of lithia, ..... 92'26 

 Caustic lithia, Li 2 0, ..... 7 - 74 



100-00 



Experiment II. — Carbonate taken = 0*8486 grm. ; the maximum temperature 



having been reached, the heating was continued for five hours. The residue then 



weighed by 0*1360 grm. less than the original carbonate. After other five hours' heating 



the total loss was 0*2728, which indicated that the change had not reached its end yet. 



Being, however, anxious to know the state of matters at that stage, I caused Mr 



Anderson to stop the experiment and analyse the product. 0*5484 grm. gave 0*2268 of 



C0 2 and 1*1780 of Li 2 S0 4 , whence we had — 



Lithia, . . . 58-620 Carbonate of lithia, . . 69*592 



Carbonic acid, . . 41-357 Oxide of lithium, . . 30-385 



99-977 99-977 



corresponding to the formula Li 2 0-f 0*4817CO 2 , or approximately to Li 2 C0 3 + Li 2 0. 

 This goes a certain way towards confirming my surmise as to the existence of a stable 

 basic carbonate ; yet I am inclined to think that all the carbonic acid can be expelled by 

 heating in nitrogen, provided only we heat long enough. 



* Note lost. 



