At^soTiPTivK ro^v^:t^ of titk snTT,. fiAt 



monia, in order to asceitain whether tlie formation of a 

 Bohible salt of the (lis[)laccd base limited the reaction; 

 but the results were substantially the same as before, as 

 shown by analyzing the residue after removing carbonate 

 of lime by digestion in dilute acetic acid. 



Eichliorn found that the artificial soda-chabazite re-ex- 

 changed soda for lune when digested in a solution of 

 chloride of calcium ; in solution of chloride of potassium, 

 both soda and lime were separated fiom it and replaced 

 by pot:i8h. So, the ammonia-chabazito in solution of chlo- 

 ride of calcium, exchanged ammonia for lime, and in so- 

 lutions of chloi-ides of potassium and sodium, both am- 

 monia and lime passed into the liquid. The ammonia- 

 chabnzite in solution of sulphate of magnesia, lost ammo- 

 nia but not lime, thougli doubtless the latter base would 

 have been found in the liquid had the digestion been con- 

 tinued longer. 



It thus appears that in the case of chabazite all the 

 protoxide bases may mutually re})lace each other, time 

 being the only element of difference in tlie reactions. 



Similar observations were made with natrolite (hydrous 

 silicate of alumina and soda,) as well as with chlorite and 

 labradorite, although in case of the latter difficultly de- 

 composable silicates, the action of saline solutions was 

 very slow and incomplete. 



Mulder has obtained similar displacements with the 

 ZL'olitic minerals stilbite, thomsonite, and prehnite. {C/te- 

 mie der Ackerkrume, T, 396). He has also artificially 

 prepared hydrous silicates, having properties like those 

 of Way, and has noticed tl:at sesquloxide of iron readily 

 participates in the displacements. Mulder also found that 

 the gelatinous zeolitic precipitate obtained by dissolving 

 hydraulic cement in hydrochloric acid, precipitating by 

 ammonia and long washing with water, underwent the 

 same substitutions when acted upon by saline solutions. 



