194- 0I< THE MEIONITF. 



could take for the substance in question. I remained in 

 this uncertainty, till I hud read the paper of Mr. Mohs, in 

 He suspect? it which we are informed, that Mr. Werner had not yet adopted 

 to be only a va- the meionite of Haiiy as a distinct species, suspecting it may 

 spar! " "^ * " be nothing Kiore than a simple variety of feldspar. Now the 

 object of this paper is to demonstrate the reality of what is 

 but a simple conjecture on the part of a naturalist, who 

 knows when to doubt, and when to decide. On reading it 

 with that double attention, which the name of Werner and 

 the talents of Mr. Mohs would naturally inspire, I felt in 

 spite of myself the regret of not being able to embrace the 

 same opinion respecting the nature of the mineral that 

 forms the subject of the present paper. 

 They do not Mr. Mohs admits, that the characters taken from figure 



' " to r , y^jjj^jj. g,-ej^t differences between the meionite and the feld- 



spar; and he confesses, that these differences are little capa- 

 bnt supposed ble of being reconciled: but, as he thinks it not altogether 



to be reducible . .,, 1,1 c <- . 1 



tooneeom- impossible, to reduce the torms ot the meionite to a very 

 mon form. simple form, which he has observed in the series of forms 

 presented by feldspar, he has flattered himself with being- 

 able to justify completely the suspicion of Mr. Werner. 

 The geometrical form in which he gives the proofs alleged 

 in his paper has enabled me to combat them with the same 

 weapons. I appeal therefore to these geometrical reasons, 

 which are employed with the more propriety in the present 

 case, because it is only by the help of the nicest precision, 

 that an able hand has traced the line of demarcation between 

 the meionite and other species of the mitierul kingdom. 

 A species cai) It is a principle generally admitted, even by the confession 

 have but one ^^ ^i^. -^ify\^^* that in a mineral species there can be but 



prunitive form, ... . 



and iis inie- one primitive form, and one single form for its integrant 



grant molecule j^l^P^^jgg^ To prove therefore, that the meionite cannot 

 the same. . _ ' 



be a variety of feldspar, it is sufficient to demonstrate, that 



the primitive forms and integrant molecules of these two 



minerals are v^'ry different. 



* " Es ist ein grundsatz dass in eincv gattung nur cine kerngestalt, und 

 nur eine integrirendes moiecul, vorkomnien koennen ; und der orictog- 



nost traegt kein bedenl.en dicsen grundsatz in seiner vollen all<je- 



meinheit geltcn zu lasseii." Ephemerides of Baron Moll, Vol. II, Part 

 I, p. 15, 1806. 



I. Fehl' 



