T. STERUY HFINTT. 37-i*i 



includes both the vegetable and the animal. These two, 

 notwithstanding the apparently close affinities between 

 flie lowest forms of each, arc, on the whole, clearly dis- 

 tinguished. We thus arrive at the three great divisions 

 commonly called kingdoms of nature, the mineral, the 

 vegetable, and the animal. These distinctions are found 

 at the basis of what we appropriately call Natural His- 

 tory, that is to say. the history or the knowledge of 

 natural bodies. The student of these notes the density, 

 cohesion, color and geometric forms of mineral species, 

 and the details of structure in plants and animals. From 

 the observation of all these characters, and the consider- 

 ation of differences and resemblances, men have con- 

 structed systems of classification in mineralogy, botany 

 and zoology ; have devised a terminology and a nomen- 

 clature ; and have thus, in each of the three kingdoms of 

 nature, organized a body of knowledge which we desig- 

 nate as systematic and descriptive mineralogy, botany 

 and zoology, or the physiography of minerals, plants 

 and animals ; the study of which, as a whole, is some- 

 times conveniently comprehended under the title of 

 General Physiography, that is to say a description of 

 nature. This, in its wider sense, includes not only the 

 individual objects belonging to each one of the three 

 kingdoms of terrestrial nature, but the earth as a whole, 

 including geography and geognosy, and extending its 

 field into other worlds, embraces descriptive astronomy. 



Having thus laid the foundation of the knowledge of 

 natural objects by a study of their sensible characters we 

 proceed farther to investigate their properties and 

 functions; in other words, their various activities, the 

 changes to which they are subject, their origin, growth 

 and decay. 



All of these phenomena may be conveniently consid- 

 ered under three heads. The first of these includes the 

 relations of natural objects to gravity, cohesion, light, 

 heat, electricity and magnetism, and it is these simple 

 non-chemical relations alone which, as we have seen, are 

 frequently designated as physical, a term which in this 

 connection may perhaps be advantageously replaced by 

 dynamical, since some of the highest authorities include 

 the phenomena in question under the general title of 

 dynamics, Under the second head come the chemical 



