22* ON A N.VTUIUL SYSTEM 



only one that leads to a knowledge of princi- 

 ples, both as to quality and quantity ; and i here- 

 to re indifpenfably ncceilary in every enquiry in- 

 to coin poll tion. 



} XLIII. The Difficulty if founding a Svflcm of 

 Foffih. 



IT was the opinion of the celebrated Lehman, 

 whofc judgement in fuch mutters was unqueili- 

 onable, that a thoutand years would not be fuf- 

 ficient for the conftrudiun of a fyftem of tollils, 

 arranged according to proximate principles, on 

 account of the immenfe number of various fofiils, 

 and the daily augmentation it is receiving; the 

 variety and cxpence of the neceflary expe- 

 riments, and the want of a more general fpirit 

 of adventure and induilry rcquiiitc for fuch uii 

 undertaking. 



J XLIV. Internal ami external Cbaraflcrs. 



A collodion of thofc properties on which the 

 leading principles depend, is called the internal 

 churach'r ; and the chief fupcrficial marks of a- 

 uy foflil taken together, conflitute the external 

 character. 



OF 



