INTRODUCTION. Xv 



though that patient writer had only mentioned it, to inform 

 his readers that it was unslacked lime, which had fallen from 

 a broken cart. 



Such tourists, while they have themselves seen as little as Study of rocks, 

 they have read, are as loud as Dr. Meara in their assertions 

 that rocks can only be studied in nature j while, in fact, it is 

 as impossible to discern rocks from nature alone, as from 

 books alone. The one must assist the other. The vague- 

 ness of ideas in the works of Dolomieu and Faujas, and 

 many other observers, is such that nothing can be learned. 

 But how distinguish rocks, or acquire accurate knowledge, Necessity of 

 from works of which the authors cannot distinguish a granite 

 from a porphyry, &c. ? If, in zoology, a horse was called a 

 lion by one writer, a tiger by another, a leopard by a third, 

 and a panther by a fourth, what knowledge could be acquired ? 

 or if, in botany, the rose of one author was the lily of an- 

 other, while others styled it by a hundred different names ? 

 While Buffon and his disciples speak with contempt of nomen- 

 clature, they might as well tell us that in civil history the 

 actions of Pompey might be ascribed to Caesar, and those of 

 Anthony to Cleopatra, for of what consequence are names ? 

 Saussure, with his usual judgement, pursued a very different 

 course ; and the most laborious parts of his work are evi- 

 dently those in which he attempts to establish a precise 

 nomenclature. It may safely be asserted that the science can 

 have no foundation till a precise and rich nomenclature be 

 established j and that till then it will remain a chaos, and 

 not a world. 



The student of rocks must therefore begin with a precise 

 nomenclature, as otherwise his observations cannot be of the 

 smallest utility. If he mean to pursue this study, he may 

 also find it more interesting to pass from this arid subject 

 to the beauties of crystallisation and the metals -, and thus 

 from great and general ideas descend to minute. The 

 student of zoology would scarcely begin with entomology. 

 But even among the authors of mineralogy there are ore and 

 dross : and who would believe that an hundred authors have 



