INTRODUCTION. 19 



The four ancient elements, earth, air, fire and water, were assum- 

 ed at hazard, because they are so conspicuous and important ; the 

 conception was grand but it was wholly erroneous. 



Instead of four elements, we have at the present time not less 

 than fifty, nearly four fifths of which are metals ; the remainder 

 are chiefly combustibles, and bodies, which, combining with com- 

 bustibles and metals with peculiar energy, are generally called support- 

 ers of combustion.* 



Our simple bodies then are 



1. Metals, about 40f 



2. Combustibles not metallic, 7-j- 



3. Principles or supporters of combustion, 2 or 3 



4. One body, or possibly two { of an undetermined char- 

 acter; in all 50 or 51 



5. Imponderable bodies, light, heat and electricity; besides the 

 power called magnetism and the other varieties of attraction. 



The principal object of chemistry is to display first, the great 

 powers upon which its phenomena depend ; and secondly, the proper- 

 ties of the elements, the mode and energy of their action, the combi- 

 nations which they are capable of forming, the properties of the result- 

 ing compounds, and the laws by which they are governed. This 

 statement, obviously, includes all bodies natural and artificial. There 

 are many chemical compounds made by art, which, as far as we are 

 informed, do not exist in nature, and there are many natural bodies 

 which art has not yet been able to imitate. 



The philosophical chemist studies both the properties of the ele- 

 ments, and the constitution of the intermediate or proximate com- 

 pounds of the whole material world, as far as it is tangible by man. 

 Of the chemical constitution of the planetary and stellary bodies, we 

 have no knowledge, except from the hints that are afforded by the 

 occasional projection to our earth, of stony masses, severed by ex- 

 plosion from luminous meteors or fire balls, which occasionally pass, 

 with great velocity, through our atmosphere. 



It will be easily understood, that the philosophical chemist under- 

 takes an arduous and responsible duty, involving much manual skill 

 and labor and mental effort, but the reward is rich and gratifying. 



* Some object to this phrase, preferring to consider combustion as being only an ex- 

 ample of intense chemical action ; this view is philosophical ; but combustion is so fre- 

 quent an occurrence and involves so many imporant chemical events, that it is con- 

 venient, in accordance with the general practice of mankind, to designate it and 

 the bodies concerned in it, by a peculiar phraseology. 



t It is perhaps doubtful where some of these bodies ought to be classed whether 

 among metals, or combustibles. 



t Perhaps silicon and bromine ; we have however classed them where they ap- 

 pear to belong. 



