286 Oliervations on 



t« confute, sufficient to have exercised the tuperior talents of this 

 gentleman, even with his understanding open. 



I shall now proceed to substantiate these deductions. 



First. As to the density of the gaseous medium. We are 

 told by Sir Richard in his Treatise, page 21, " that the den- 

 sities are supposed such, that, multiplied by the distances, the 

 products are equal * : consequently, as the distances increase, the 

 densities must of course decrease." 



Again: page 25, " The density of each stratum is inversely 

 as the cubes of the radii." 



Secondly. As to the density of the planets. 



Page 19. " We know from the diurnal phzenoraena that the 

 earth and atmosphere have such a common rotatory motion, 

 without which the common orbicular force must confer on the 

 masses unequal momenta. It is however a necessary mechanical 

 effect of such common rotatory motion, to equalize the momenta 

 of masses of various density, and to force them to range them- 

 selves, or to seek to range themselves, in concentric circles or 

 radii of rotation, inversely as their respective densities. By their 

 mutual collisions the lighter bodies must, by the mechanism of 

 equal momenta and equilibria, ascend Jrom the centre toivards 

 the circumference, and the heavy ones he forced towards the 

 centre." 



Whence the same effects must evidently obtain in tii?" planet- 

 ary system; for the rotatory motion of the gaseous medium and 

 the rotatory motion of the earth's atmosphere, on this principle 

 of mechanics, must undoubtedly produce similar results. 



We are also told at page SfJ, " that if the density of the pro- 

 jectile were equal to the density of the medium, then the pro- 

 jectile would float in the medium, and he carried round the earth 

 in the circular vortex of the earth like th.e medium itself." 



On the same theory, the planets would fall to the sun, unless 

 supported by a medium of equal density with the respective 

 planets — as it is evident they must swi7n in a medium of the 

 same density and velocity — otherwise resistance would be ge- 

 nerated till this efi'ect was obtained. 



Whence the density of the medium and the density of the 

 planets in the same circle of rotation must of necessity be equal, 

 and, on the principles of Sir Richard's Theory, their densities 

 undeniably decrease from the sun to the confines of the solar 

 system, as I before asserted ; or, from the centre of any revolving 

 medium or system of bodies, to the extent of their circumference. 



Fierilatis admits as granted, that a cubic foot of silver cannot 



• This law involve* the absurdity, that the sun and planets, and all rota- 

 tory bodies, are infinitely dense at their centre* ! !. Subiime resvltt, and not 

 vnworthy of furthtr tpeeukition ! 



be 



