2 INTRODUCTION. 



be 1 Defined with precision : and into whatever path we chance to 

 strike, difficulties from the very nature of the case are unavoidable. 



The Natural Sciences relate either to Nature and her several 

 products considered by themselves : or they teach us so to apply 

 those products as to contribute to our service, or to satisfy our 

 wants. The latter are called practical natural sciences, the former 

 theoretical. To the practical natural sciences belong especially 

 Agriculture and Technology : and they are founded upon the 

 theoretical, of which the truths are applied only in a degree propor- 

 tioned to the particular object that is had in view. They may 

 therefore be called Applied Natural Sciences. Of the pure, or 

 theoretical Natural Sciences there are several. To them belong 1 

 Phenomenal Doctrine, Chemistry, and Natural History. What 

 characterises such sciences and distinguishes them from each other 

 lies less in the objects which belong to the province of each, than 

 in the manner of considering them, and in the different direction 

 of the enquiry. Metals, salts, earths belong as much to the province 

 of Chemistry as to that of Natural History : but the chemist, in 

 all these things, investigates only the matter and its properties, its 

 affinities and combinations : the mineralogist is busied with their 

 form, their natural occurrence, their classification. The chemist, 

 moreover, investigates those elements which occur in nature only 

 in combination with other matters : such elementary substances are 

 excluded from the province of Natural History. 



Whilst Physics investigate the common properties of bodies, and 

 the motions by which a temporary change is effected in their 

 condition, Chemistry enquires into their component parts, the 

 special properties of each elementary substance, and its various 

 combinations with other elementary substances. Natural History, 

 finally, arranges the bodies occurring in Nature according to form. 

 In a certain sense, therefore, it may be termed a special Phenomenal 

 Doctrine : but its essence lies in describing and classifying. It is 

 ordinarily limited to the bodies which occur upon the surface of 

 our earth, or at small depths below and accessible by mining : but 

 it is by no means necessary thus to limit it. It depends upon the 



1 [Natwr-lehre, The vast body of observed facts throughout nature " bound together 

 under the form of laws and principles." Vid. WHEWELL'S History of the Inductive 

 Sciences, and his Philosophy of the Inductive Sciences, passim.] Tr. 



