^•N Mr. Herapatkontke Causes, Laws ^and principal [April, 



On the Physical Constitution of the Universe. (In a Letter to 

 Davies Gilbert, Ifisq. MP. FRS. &c.) 



DEAR SIR, 



'■ ' In the following memoir, which I have to request you will do 

 me the honour of submitting to the consideration of the Royal 

 Society, I have endeavoured to unravel the causes of some of 

 tile leading phaeriomena of the universe, such as those of heat, 

 gravitation, &c. That a correct judgment may the more easily 

 €e formed of the nature of this memoir, I have prehxed a brief 



-account of the train of thought I pursued in my investigations, 

 which will tend to throw a considerable light over what follows. 

 And because I conceive no theory established, however well it 



' may accord with phsenomena, unless it can be shown all others 

 do not, I intended to take a review of some of the principal hypo- 



* theses that have been advanced and supported by different phi- 

 ' losophers, and to show wherein I think them defective; but 

 ■ afterwards considering that this would extend the memoir to a 



much greater length than I wish, and that I might probably be 



obhged to press a little hard on the favourite opinions of some 



respectable philosophers, I have for the present laid this design 



" aside. For similar reasons I have omitted all comment and 



* comparisons, except what are necessary for the elucidation of the 

 •subject. I have likewise, in consequence of a conversation that 



I lately had with W. Clayfield, Esq. materially changed the plan 

 of this memoir, so as to render the connexion and dependence 

 between the principles and consequences more apparent. And 

 in order to trespass as little as possible on the time of the Royal 

 Society, I have only demonstrated some of the elementary pro- 

 positions ; reserving the proofs of others to a future period, when, 

 if the little that 1 have done receive the countenance of the 

 Royal Society, 1 might be induced to take a more elevated view 

 of the subject, and to touch upon other things that are not men- 

 tioned. 



The Royal Society will easily perceive that I am indebted for 

 the hint of the cause of gravitation to Sir Isaac Newton, though, 

 perhaps, it will be found, that I have carried the idea much fur- 

 ther, and have extended it to the development of a much greater 

 Tariety of phenomena than he could have anticipated. It would 

 be preposterous for me in this place to name other distinguished 

 philosophers to whose accurate experiments and luminous views 

 1 have, in the course of my inquiries, been under great obliga- 

 tions ; but I cannot let slip this opportunity of acknowledging, 

 that if it shall appear I have been any way successful in my soli- 

 tary rambles through these exalted regions, it is probably in a 

 great measure owing to your kind encouragement and directions, 

 and to the flattering approbation you were pleased to bestow on 

 my juvenile efforts so long ago as the beginning of 1809, when I 

 had the pleasure of being introduced to you l^ my late respected 



