M. Scheerer's Observations on Elaeolith and Nepheline. 119 



Now since the weight of 1 at. of carbonate of lime is 632, it 

 results that considerable differences must originate by these 

 different atomic values on the per centage calculation of the 

 constituents of a combination of both atoms. In fact, were 

 the atomic weight of elaeolith = 5529 the cancrinite ought not 

 to contain more than about 10 per cent, carbonate of lime; 

 while, according to my formula, it should contain 14 per 

 cent. But the latter number is likewise confirmed by the 

 two analyses of G. Rose. 



IV. COLOUR OF THE EL.ZEOLITHS. 



Only two of the analysed varieties of this mineral possess 

 colour, those from Fredricksvarn, the one green, the other 

 brown. When both are finely powdered and decomposed 

 with concentrated hydrochloric acid, the silica separated has 

 the same colour, only in a less degree. This is especially 

 evident in the green elaeolith, which is more intensively 

 coloured than the brown, and with which I therefore chiefly 

 performed experiments. Even when the concentrated hydro- 

 chloric acid is evaporated, and the dry mass again moistened 

 with acid, and treated with water, the filtered silica still re- 

 tains its colour, which, however, immediately disappears on 

 heating the silica. It is further destroyed when the silica is 

 heated with nitric acid, or the mineral decomposed by fuming 

 nitric acid. This latter action sufficiently proves the colour 

 to be of organic origin. But the colouring substance must 

 certainly be of a peculiar nature, as it withstands the action of 

 fuming, nay, even chloriferous hydrochloric acid. 



The following are the main results afforded by these ex- 

 aminations of the elaeoliths. 1. The formula for elaeolith 



TVT 2 I * 



and nepheline must be altered to a < Si + 2 Al Si. The 



Ka 2 I 



atomic relation of soda and potash is as 4 : 1 Both mine- 

 rals are perfectly identical, the latter being merely character- 

 ized by a somewhat greater amount of lime. 



2. Elaeoliths, from the most varied localities, exhibit traces 

 of hydrochloric and sulphuric acids, especially of the former. 



3. The amount of water in elaeoliths varies considerably, 

 and must be considered as accidental. 



It is probably only hygrometric, and is perhaps prevented 

 from evaporating at 80 R. by a force similar to that which 

 several porous bodies exercise on gaseous substances. 



4. The colour of some elaeoliths is of organic origin. 



5. The specific gravity of the elaeoliths is exceedingly near 

 to 2-6. 



