ON SHOOTING STARS. gS5 



of the triangles ABX, ABY ; and if M /, M X, be drawn 

 perpendicular to Bw, the triangles ABV, BM/, will be simi- 

 lar, and also the triangles ABy, BmX : Hence we obtain 

 AB : AY::rBM: B/, and 

 AB : Ay=BM : Bx 

 Therefore, ex «9«o, AY : A yrrB / : Bx 

 Complete the parallelograms BM o N, Bmun; and B/, 

 Bx will be respectively one half of tlie diagonals Bo, Bu>. 



Now let two equal forces BM, BN, act in these di- 

 rections upon the lever at B, their joint force will be re- 

 presented by the diagonal Bo, and consequently one of the 

 forces BM will be represented by B/n| Bo. In the same 

 manner, if the two equal forces Bm, Bn, act upon the 

 lever at B, their joint force will be represented by B w, and 

 one of them, Bto, will be represented by Bkzz^Bw, 

 Consequently the power of the two forces BM, Bm, to 

 turn the lever roynd its centre of motion, is represented 

 by B /, B X, respectively; that is, the force BM is to 

 the force B m as B/is to Bx ; that is, as AY is to Ay, 

 the perpendiculars let fall upon the lines of their di- 

 rection. 



VIII. 



On the Nature of those Meteors commonly called Shooting 

 Stars. In a Letter from John Farey, Senior , Esq. 



To WILLIAM NICHOLSON, Esq. 

 SIR, 



JLN several Meteorological Reports of late, and particularly 

 in a letter from Mr. Thomas Forster, at page 131 of your Shootingr stars 

 October number, the appearances usually denominated connected^ 

 shooting stars are noticed, and treated of as being a pheno- with electrical 

 menon connected with the electric and other particular "^"^'^^Y^^^*^* 

 state of our atmosiphere, particularly •' clear dry weather mosphere. 

 " and easterly winds," *' cUar frosty winter nights," and Its cleamrss 

 *' the clear intervals of showery weather." Now these three ^PI'^''^"'^^ "^ 



states 



