Mr A. Conneirs Analysis of Gmdinite or Hydi-oUte. 363 



It sufficiently appears, both from the analyses of Vauquelin 

 and from that here detailed, that this mineral is nearly allied 

 to chabasite, in a chemical point of view, as, according to Mr 

 Haidinger, it is crystallographically ; and it is not impossible, 

 that if analyses applicable to different localities were repeated 

 and sufficiently extended, the chemical formula for chabasite 

 might be found to embrace gmelinite. It does not, however, 

 apply to the above analysis, and still less to those of Vauque- 

 lin. The formula indicated by the above result is, (C NK) S^ 

 + 3 Al S^ + 7 Aq. ; and it may be noticed that whilst this for- 

 mula exhibits one atom of silica and one atom of water more 

 than that for chabasite, the formula which a former analy- 

 sis of levyne, a mineral also nearly allied to chabasite in a chemi- 

 cal view, suggested, shewed one atom of silica and one atom of 

 water less than in chabasite ;* and that in gmelinite, bisilicate 

 of alumina is associated with tersilicate of lime and alkalies ; 

 in chabasite, with bisilicate ; and in levyne with silicate of these 

 bases ; as appears from the formulae : 



(CNK; S' + 3 A1 S^ + 7 Aq. Gmelinite. 

 (CNK) S« + 3 Al S« + 6 Aq. Chabasite. 

 (CNK) S + 3 Al S2 +5 Aq. Levyne. 



I have much less expectation that the chabasite formula will 

 ever be found to embrace levyne ; because the proportion of si- 

 lica and that of alumina, actually found in the latter mineral, 

 differ in a marked manner and in opposite directions from those 

 in chabasite ; whilst in gmelinite the difference is much less 

 considerable, although still excluding the chabasite formula.-f- 



* London and Edin. Jour, v, 40. 



-f It was objected, on high authority, to the formula for levyne, that the 

 alkaline bases cannot be in a lower state of saturation than the earthy, be- 

 cause they will, by their stronger affinity, take silica from the latter. I5ut 

 might not a similar argument be employed against their ever being in an equal 

 state of saturation ; and may it not be asked, how, on this principle, an alka- 

 line base should ever rest satisfied until it had at least got into that state of 

 saturation which the same high authority considers to be the neutral state ? It 

 does not seem very unreasonable to suppose, that the relative states of .satu- 

 ration may be influenced by the relative (quantities of acid and bases present. 



