304 REMARKS OK MR. VfNCE's PAMPHLET. 



XT. 



Remarks on a Pamphlet, lately published by the Reverend 

 S. Vincr, respecting the Cause of Gravitation. By a Cor- 

 respondent. 



To Mr. NICHOLSON. 

 SIR, 



Mr. Vince's JlT is not long since I first saw Mr. Viuce's pamphlet re- 

 thecausc of s P ectm & Sir Isaac Newton's conjectures on the cause of 

 gravitation. gravitation ; some parts of it appear to me so erroneous and 

 so injudicious, that I think it right to take the first oppor- 

 tunity of expressing the disapprobation, which the author 

 seems to deserve. 



Cannot be the After having shown, that the established laws of srravitu- 

 pressure of a ° . jf 



medium vary- tion cannot be derived from the pressure of a medium, of 



ing in density which the density varies simply as any given power of the 



of the distance! distance, Mr. Vince proceeds in these words , (P. 21), " It 



may be supposed, that if the above assumed law of density 



of the fluid will not answer the required conditions, yet some 



other law of density, which is compounded of different 



powers of the distance, may be made to agree with the law 



of gravity. Let us therefore represent the density of the 



medium by P a m + Q a 1 4- R a* + & c « — Hence, according 



to the foregoing reasoning (taking only the two first terms 



of the series), the law of force tending to the sun is 



p x 2 '"-'"" x a fei? - 1 + Q X a VttZ x a' 2 -£=^- 



3e 2 He 2 



1 -\- R, &c. Now these, being different powers of the dis- 

 tance a, the whole can never constitute a power which varies 



Mis mistake as —77." On this point the Professor's whole demonstration 



pointed out. aZ 



rests, and it is difficult to imagine how he could have com- 

 mitted so palpable a blunder. We have only to put m — 0, 

 and R ~ o, in order to show the fallacy of his reasoning : 

 the force will then be respresented according to the expres- 

 sion here laid down, by Q X !£Z£J X ?±ZlI!_ lf ' and 



a e '<5 



"? qn — j 11]av become ~ — 2 on many suppositions, while 



the 



