[ 86 ] [Book II, 



BOOK II. 



OF THE NATURE OF FIRE, 



CHAP. I, 



HISTORY OF THE DISCOVERIES RELATIVE 

 TO FIRE AND HEAT. 



Opinions of the Ancients. -Of Bacon, Boyle, and Newton. Of Horn- 

 bergy Sgravefend, and Ltmery. Invention of the ^Thermometer. 

 Opinion of Boerhaave.* Great Difco-very of Dr. Black. 



SO wonderful is the nature, fo extenfive is the action, 

 and fo formidable is the power of fire, that by 

 one of the moft confiderable nations of antiquity * it 

 was adored, as the embodied prefence of the fupreme 

 God : and even in countries where the adoration was 

 lefs palpable and direct, fomething myfterious was al- 

 ways attributed to this fubtile and aftonifhing ele- 

 ment j and the rites and myfteries of fire were cele- 

 brated in temples and in groves, from 'the Ihores of 

 the Hellefpont to the banks of the Tiber. 



An opinion feems to have been prevalent among 

 the early phiiofophers of Greece, that fire is the only 

 elementary and homogenial principle in nature, and 

 that from its different modifications all this variety of 

 different bodies is produced f. This idea is ridiculed 

 by Lucretius, who adopts the fyftem of Epicurus: and 



* The Ferfians. See Herod, Lib. II. c. 18. 

 f Lucret, Lib. 1. 636. 



indeed 



