23 



Oxide of zinc, 67-792 



Silicic acid, 23-424 



Carbonic acid, 1-421 



Water, 7-263 



99-900 



If we look upon the carbonic acid as existing in a compound 2 ZnO, 

 COjjHO, that is in a corresponding degree of hydration to that in which 

 silicate of zinc is found, the proportions in which the silicate and car- 

 bonate in the mineral will be found to be, in 100 parts : — 



2ZnO,Si02,HO, . . . 92-702 

 2ZnO,C02,Ho, . . . 7-298 



100-000 



7'298 of this hydrocarbonate would contain : — 



ZnO, 5-296 



CO2, 1-421 



HO, 0-581 



7-298 



If we deduct these numbers from those given above in the table of 

 the results of the analysis of the mineral, we shall get the following pro- 

 portions, which represent the quantities of oxide of zinc and water which 

 belong to the sHicate, as distinguished from those which belong to the 

 carbonate : — 



ZnO, . 62-596 



SiOa, 23-424 



HO, 6-682 



92-702 



Or in 100 parts, and compared with the composition of silicate of 

 zinc calculated from the formula 2ZnO,Si02,HO : — 



Calculated from Calculated from 



the Formula, the Analysis. 



2ZnO, . . 67-213 .... 67*523 

 SiOa, . . 25-409 .... 25-268 

 HO, . . 7-377 .... 7-207 



99-99 99-998 



The ratio between the number of equivalents of silicate and carbonate 

 deducible from the preceding calculations is about 11:1; so that the 

 pure white, fibrous silicate may be classed in the same category as the 

 siliceous balls, and the formula ll(2ZnO,Si02,HO) + ZnO^CO^jHO, 

 assigned to it. In this case we have distributed the water between the 



