INTRODUCTION. 



motion, and qualities of light form the science of OPTICS : 

 the changes that take place in the atmosphere, as they are per- 

 ceived by the senses, or indicated by instruments, is the ob- 

 ject of METEOROLOGY : And it is the province of CHEMISTRY, 

 another great branch of Physical Science, to investigate the mu- 

 tual agencies of the elementary principles of matter upon one 

 another, their composition, and the laws by which they are re- 

 gulated. These divisions of the great field of Natural Science 

 have, from the universality of their influence, been called Ge- 

 neral Physics ; while Natural History in its limited sense, 

 and as confined to the examination of what have been called 

 the three kingdoms of Nature, viz. the Animal, Vegetable, and 

 Mineral, has received the name of Particular Physics. Natu- 

 ral History, besides, is distinguished from the other branches of 

 science now named in this, that while Dynamics is a science 

 chiefly of Calculation, and Chemistry of Experiment, the basis 

 of this great science rests chiefly on Observation. 



In the limited sense in which Natural History is thus to be 

 understood as confined to the three great divisions of Animals, 

 Vegetables, and Minerals, a System of Nature is a grand cata- 

 logue of the objects in these kingdoms, in which each individual 

 has a distinctive character and an appropriate name. These in. 

 dividuals, for the sake of arrangement, are collected into groups 

 which have something in common, and which are termed Genera; 

 Genera are further combined into other groups, which form in 

 systems what are called Orders ; and Orders are finally arranged 

 under one great head, which is termed a Class. This scale of 

 divisions, of which the highest contains the least, is, as. Baron 

 Cuvier remarks, a kind of dictionary, where theproperties of things 

 are investigated to discover their names, and which reverses the 

 usual order of such works, where the names are indicated as 

 detailing the qualities of the things named. 



But though method and arrangement form the first step to 

 the knowledge of the numerous objects which claim the attention 

 of the naturalist, Natural History is by no means confined to a 

 list of names. If the method be a good one, and the subdivi- 

 sions arranged conformably to the fundamental and natural con- 

 nections of bodies, the very arrangement and classification of 

 names of beings which have something in common, leads to the 



