INTRODUCTORY REMARKS. O 



Chemistry is not behind in its wonders. That the diamond 

 should be made of the same material with coal ; that water 

 should be chiefly composed of an inflammable substance ; that 

 acids should be, for the most part, formed of different kinds of 

 air, and that one of those acids, whose strength can dissolve 

 almost any of the metals, should consist of the self-same in- 

 gredients with the common air we breathe ; that salts should 

 be of a metallic nature, and composed, in great part, of 

 metals, fluid like quicksilver, but lighter than water, and 

 which, without any heating, take fire upon being exposed to 

 the air, and by burning, form the substance so abounding in 

 saltpetre and in the ashes of burnt wood : these, surely, are 

 things to excite the wonder of any reflecting mind nay, of 

 any one but little accustomed to reflect. And yet these are 

 trifling when compared to the prodigies which Astronomy 

 opens to our view : the enormous masses of the heavenly 

 bodies ; their immense distances ; their countless numbers, 

 and their motions, whose swiftness mocks the uttermost efforts 

 of the imagination. 



Akin to this pleasure of contemplating new and extraordi- 

 nary truths, is the gratification of a more Jearned curiosity, 

 by tracing resemblances and relations between things, which, 

 to common apprehension, seem widely different. Mathemati- 

 cal science to thinking minds affords this pleasure in a high 

 degree. It is agreeable to know that the three angles of 

 every triangle, whatever be its size, howsoever its sides may 

 be inclined to each other, are always, of necessity, when 

 taken together, the same in amount : that any regular kind of 

 figure whatever, upon the one side of a right-angled triangle, 

 is ecnial to the two figures of the same kind upon the two 

 other sides, whatever be the size of the triangle : that the 

 properties of an oval curve are extremely similar to those of a 

 curve which appears the least like it of any, consisting of two 

 branches of infinite extent, with their backs turned to each 

 other. To trace such unexpected resemblances is, indeed, the 

 object of all philosophy; and experimental science, in par- 

 ticular, is occupied with such investigations, giving us general 



B 2 



