4to Rmarks on tlu Enquiries of Dr. Herfthel refpe3itig Ughl and Heal. 



but a coarfe one. After fuch aconfeffion, your reacJers will judge what degree of credit it . 

 really deferves. Is it at all likely, may poflible, that fo many able philofophers, who for 

 above a century back, have employed their talents on the improvement and application of 

 , the burning glafs, fliould have totally overlooked a fact fo obvious and fo palpable. The 

 Do£tdr has a remarkable faculty, not peculiar to him however, of flurrinj; over thofe 

 points which immediately aflecl his opinions, and of dwelling with minutencfs on what 

 nil the world may be prefuraed to know. Had he uniformly exercifed the fame laudable 

 fcepticifm which he profelTes at the outfet, he might perchance have doubted whether his 

 precurfors were not Cometirres right, and himfelf miftaken. It would require more than 

 ordinary docility to believe Dr. Herfchel's " coarfe" experiment, in oppofition to all the 

 former concurrent teftimonies. 



I now take leave, I hope for ever, of this controverfy. Without queftioning Dr. Herf- 

 chel's fidelity, I have (hown that his affertions are not only inconfiftent with all our general' 

 and beft founded notions, but ftand direftly contradided by aftual obfervations made with 

 peculiar advantages ; that his experiments were injudicioufly contrived, executed without 

 circumfpeftion, and liable to a multiplicity of inaccuracies \ that his reafonings, how boldly 

 foever advanced, were ftill more defective ; that his later experiments are the more vulne- 

 rable in proportion to the confident tone which he aflumes ; that by far the major part of 

 them is totally unconnefted with the fubjeft in difpute, and only twilled to ferve his pur- 

 pofe by the fophiftical tranfpofition of terms ; and that the few which aftually apply are of 

 fuch obfcure and ambiguous character as to afford no certain evidence. In fliort, thofe ex- 

 periments and conjectures, taking their combined impreflion, may for a while gratify vul- 

 gar curiofity, but mutl foonhaften to final oblivion. I fliould be forry if my ftridlures gave 

 offence to Dr. Herfchel. If I have fpoken with freedom, I truft it is in the language which 

 conviction and the love of truth naturally infpire. Undue authority, always depreffmg, is 

 capable of producing moft fatal effects, when fuffered to gain poffeffion of the fciences. 

 How long did the afcendancy of Ariftotle, of Des Cartes, and fhall I add in fome few 

 points that of the venerable name of Newton, retard the advancement of real know- 

 ledge. I refpect Dr. Herfchel's talents, I admire his aftronomical difcoveries, and I ani 

 perfuatled that England, in the decline of her fcience and philofophy, needs the importa- 

 Uo of genius from abroad, and is honoured by becoming his adopted country. If I cannot 

 equally approve of feveral of his late fpeculations, I reflect that men feldom eftimate ariglit 

 their own powers, feldom know where their real ftrength lies. Adventuring on new fub^ 

 jeCls they are not likely all at once to acquire the flcill, precifion, and caution which are 

 generally the fruit of experience and patient application. 



But I cannot finifh the letter without addreffing a few words to you, Sir, as editor of a 

 refpeftable Journal. I advert to the note with which you have honoured me at page 34S. 

 I cettainly prefumed that you gave unchanged the ideas, if not the words of your author. 

 In this it appears I was miftaken ; and I chearfully retra£V the expreflion to which it gave 

 rif«, aod ^(^fhich were merely ihe fpontaneous effufion of tlie moment. Dr. Herfchel only 



ftippofes,. 



