Objects, Advantages, And Pleasures Of Science.

natural that the stone should fly upwards or stand still , as that it should fall down . But no degree of reflection for any length of time could accustom us to think 2 and 2 equal to anything but four , or to believe the whole of anything equal to a part of itself .

III . NATURAL OR EXPERIMENTAL SCIENCE . Natural jihilosophy , in its most extensive sense , has for its province the investigation of the laws of matter , that is , the jmoperties and the motions of matter ; and

it may be divided into two great branches . The first and most important ( which is sometimes , on that account , called Natural Philosophy , by way of distinction , but more properly Mechanical Philosophy ) investigates the sensible motions of bodies .

The second investigates the constitution and qualities of all bodies , and has various names , according to its different objects . It is called Chemistry , if it teaches the properties of bodies with respect to heat , mixture with one anotherweihttaste

, g , , appearance , and so forth -. Anatomy and Animal Physiology ( from the Greek word signifying to speak of the nature of any thing ) , if it teaches the structure and functions of living bodies , especially the human ; for when it shows those of other

animals we term it Comparative Anatomy ; Medicine , if it teaches the nature of diseases , and the means of preventing them and of restoring health ; Zoology ( from the Greek word signifying to speak , of Animals ) if it teaches the arrangement or classificationand the habits of the different lower

, animals ; Botany ( from the Greek word for herbage ) including Vegetable Pysiology , if it teaches the arrangement or classification , the structure and habits of plants ; Mineralogy , including Geology ( from the Greek words meaning to speak of the

earth ) , if it teaches the arrangement of minerals , the structure of the masses in which they are found , and of the earth composed of those masses . The term Natural History is given to the three last branches taken together , but chiefly as far

as they teach the classification of different things , or the observation of the resemblances and differences of the various animals , plants , and inanimate and ungrowing substances in nature .

But here we may make two general observations . The first is , that every such distribution of the sciences is necessaril y imperfect , for one runs unavoidably into another . Thus , Chemistry shows the qualities of jilants with relation to other substancesand to each other ; aud Botany

, does not overlook those same qualities , though its chief object be arrangement . So Mineralogy , though jirincipally conversant with classifying metals and earth , yet regards also their qualities in respect of heat , and mixture . So too , Zoology ,

beside arranging animals , describes their structures like Comparative Anatomy . In truth , all arrangement and classifying depends upon noting the things in which the objects agree and differ ; and among those things in which animals , plants , and minerals agree or differ , must be considered the anatomical qualities of the one and the chemical qualities of the other .

Prom hence , in a great measure , follows the second observation , namely , that the sciences mutually assist each other . We have seen how Arithmetic and Algebra aid Geometry , and how both the purely Mathematical Sciences aid Mechanical Philosojihy . Mechanical Philosophyin

, like manner , assists , though in the present state of our knowledge , not very considerably , both Chemistry aud Anatomy , especially the latter ; and Chemistry very greatly assists both Physiology , Medicine , and all the branches of Natural History .

The first great head , then , of Natural Science , is Mechanical Philosophy , and it consists of various subdivisions , each forming a science of great importance . The most essential of these , and which is indeed fundamental , and ajiplicable to all the rest , is called Dynamics , from the Greek word signifying power or force , and it teaches the laws of motion in all its varieties . Tho

case of the stone thrown forward , which we have already mentioned more than once , is an examjile . Another , of a more general nature , but more difficult to trace , far more important in its consequences , and of which , indeed , the former is only one particular caserelates to the motions of

, all bodies , which are attracted ( or influenced , or drawn ) by any power towards a certain point , while they are , at the same time , driven forward , by some push giveu to them at first , and forcing