1'IIKFACE. XIII 



" witli consistency to a whole science, a method 

 " which, though not new in itself, had yet been dis- 

 " regarded in Mineralogy, and to remove all the 

 " difficulties arising from deficiencies I had to 

 " supply, and from errors I had to correct. This 

 " problem, however, requires so much time and 

 " labour, that the person who undertakes to re- 

 " solve it, must leave many parts to subsequent 

 " investigation, while those who judge of the merits 

 " of a first attempt of this kind, will be disposed 

 " to relax in the severity of their criticism. Yet 

 " I wish that this work may be subjected even 

 44 to the strictest examination, provided it be can- 

 " did, well grounded, and does not omit to con- 

 " sider, that at the present moment the disposi- 

 " tion~of the whole must be of greater importance 

 " than the minuter details of the various depart- 

 " meats of the work. I know none of the im- 

 " perfections still to be met with, which could 

 " not be removed by future labours, and which 

 " will not soon disappear, if I have been for- 

 " tunate enough to call the attention of natu- 

 " ralists towards the exact knowledge of the phy- 

 " sical qualities of minerals, and to induce them 

 " to investigate these more closely and accurately 

 " than has hitherto been customary. Like every 

 " other department of Natural History, Minera- 

 " logy is a charming science. But its charms are 

 " grounded only upon its exactness ; and nothing 

 " has a more baneful influence on the science itself, 



