'Oti C'i'ystallograpU^, 1 99 



<of analysis, by einploying a choice of characters happily 

 combined, some of which are presented as of themselves 

 to our senses, and the others only require, for being re- 

 gularly defined, pronipt and easy operations. 



Here crystallography, which had seconded analysis in 

 the formation of the method, wi-!l reappear to advantage, 

 m order to furnish characters founded on file amglc-s of 

 crystals, which may be measured in an instant. 



Tiius the means which have presided in the composition 

 of the method will be at the same time the most solid, and 

 those which will be the least arbitrary, and the means 

 U'hich shall direct the use of the method will have the 

 merit of simplicity and convenience. , 



It may be seen from what precedes, that a mineralogica! 

 ?»TSlem, heing complicated with characters frequently bor- 

 roweol from very different considerations, requires more 

 cautious proceeding in the person who employs it than a 

 botanical system, the uniform and regular progress of 

 which is traced according to a modification which spealcs 

 to the eyes, in suc^ a mamner that all the labour of the 

 observer is confined to the different applications of one and 

 the same principle. Btit this inconvenience, if it be one, 

 is compensated in a great measure by the advantage of only 

 having to determine among a number of species incom- 

 parably less than that which botany embraces : and the 

 method being in this respect confined in a narrower circle, 

 the observer finds his way more easily in the midst of the 

 circuits which he is obliged to take in order to attain his 

 object. We may add, that even the variety of the cha- 

 racters which he associates in one and the same inquiry, 

 and the various kinds of knowledge which he Combines 

 with the observations of what is presented to his senses, 

 contribute to give additional interest to the study of the 

 objects which interest his mind, and to render this study 

 at once more gratifying and instructiv^e. 



We have given in the preliminary discourse a detailed 

 explanation of the method which we have adopted. The 

 plan oF it has been conceived in such a manner that, with- 

 out suffering ourselves to fabricate connexions disavowed by 

 nature, with a view to anticipate the results of analysis, we 

 might profit by all those which should admit of our esta- 

 blishing a regular distribution of those parts of the method, 

 in which the labours oF the chemists have procured more 

 certain and better connected information. We have di- 

 vided the whole mineral kingdom into four classes, ,thc . 

 titles of which we here place before the reader. 



N4 1. Acidi- 



