REFORM OF MINERALOGICAL SYSTEMS. 277 



towards the object which I have pointed out. But 

 we know not yet how far we are from the end. The 

 combination of chemical, crystallographical, physi- 

 cal and optical properties into some lofty general- 

 ization, is probably a triumph reserved for future 

 and distant years (p). 



Conclusion. The history of Mineralogy, both 

 in its successes and by its failures, teaches us this 

 lesson ; that in the sciences of classification, the 

 establishment of the fixity of characters, and the 

 discovery of such characters as are fixed, are steps 

 of the first importance in the progress of these 

 sciences. The recollection of this maxim may aid 

 us in shaping our course through the history of other 

 sciences of this kind ; in which, from the extent of 

 the subject, and the mass of literature belonging to 

 it, we might at first almost despair of casting the 

 history into distinct epochs and periods. To the 

 most prominent of such sciences, Botany, I now 

 proceed. 



