and Vro^efs of the Rojal Society of hoiuhn. "i^^ 



Air. Hooke was one of the moft ingenious and indefati- 

 gable of the early members of this fociety. lie explained, 

 in an admirable paper, the beft method of making a hiftory 

 of the phaenomena of the weather. He made many experi- 

 ments, which were repeated, with many variations of cir- 

 cumftances, by the fociety, to prove, " that vifible and fen- 

 fible fire was but the acl of tlie dilTolution of heated bodies 

 by the air: that this diffolution of fiich bodies took place iti 

 a manner pcrfeftly fimilar to the folution of iron, tin, and 

 copper, by acids : that the evolution of heat and light was a 

 neceffary refult of the folution of heated and combuRiblc 

 bodies in air: that the aflies of a burnt body were a refiduum 

 of it, that was infoluble in air." This chemical theorv, as 

 the learned reader cannot but perceive, differs from that which 

 was propofed bv M. Lavoifier, and is now defervcdiy received 

 as philofophical truth, onlv in being exprelTed in the chemical 

 diale<Sl of that time, which is now obfolete; and in being, 

 in the intention of its author, to a certain degree accommo- 

 dated to other theories which then prevailed. In verifying 

 the theory of Hooke, the fociety made a number of experi- 

 ments : to afcertain how long a candle, a lamp, or ignited 

 coals, would continue to burn in a cubic foot of common, of 

 rarefied, and of condenfed ai*"; to exhibit the fudden extinc- 

 .tion of flame by the affufion of air already fatiated with burn- 

 ing, and the impoffibility of even the moft intenfe and torrid 

 heat to continue without a fupply of frefli air; and to find 

 what particular degree of heat was to be produced from the 

 burning of every aifferent combuftible material. By other 

 experiments, having a refpeft to the lame theory, they afcer- 

 tained that flame was fubjeft to be cxtinguiflicd by the air 

 in a deep well. They made befide thefe, and with a view 

 to difcern the varied phoenomena of ignition and combuftion, 

 independently of Mr. Hooke's fyftem, a great number of other 

 experiments on the bringing of copper into a (late of great 

 combuftibility, on the igniting of tin filings by the help of 

 nitre, &c. &:c. 



They inltituted a multitude of experiments to determine 

 the nature, properties, and ufesofair. By the. care efpe- 

 cially of Mr. Boyle, many trials were made to find, by means 

 of the barolcopc, the dift'crcnt degrees of the prediue or irrar 

 vity of the atmofphere at ditferent heights and depths. They 

 took much pains to difcovcr the oppolite limits of the rare- 

 faction and the condcnfation of air. They made a variety 

 of experiments on the propagation of found in r.ir: and w>hat 

 is, in a chemical point of view, highly remarkable, a number 

 of their experiments were dirci^ted to afccrlaiu "' the gencra- 



C 3 tioa 



