Effects of the Orlicular and Rotary Motions of the Earth. 433 



nascent deflection, however, at E would be but an infinitesimal 

 of the said 20 seconds ; consequently, any indefinitely small de- 

 ilective force, arising from new couibinatioiis of the forces, might 

 be sufficient to return a body to the earth. 



What then is the actual deflective force which turns a projec- 

 tile downward, and prevents it from moving for ever in the place 

 in the atmosphere in which it has been left by the extinction of 

 that projectile force, which carried it from the surface into so 

 novel a situation in the atmosphere ? 



Let us examine all the circumstances in which the body has 

 been placed : — 



1. // luas moving ivith the earth in its orbit tvith all other 

 lodies upon the earth, and therefore possessed a momentum in 

 that direction, which, with regard to other bodies, was as their 

 quantities of matter. 



2. It toas deflected aside by some novel muscular or explosive 

 force, and throw Ji towards D. 



3. But, while it was moving towards D, or 16 feet and an 

 inch, it was carried 6000 limes as far, or 1 00,000 /eef at right 

 angles; and therefore performed a diagonal. 



4. At C It loses its force in the direction at D, and is de- 

 flected towards the earth, at B. 



Let us now examine what other circumstances have attended 

 its ascent : — 



1. Its passage has been made in a resisting medium, which 

 tended, as is knoivn, constantly to destroy the force with which 

 it was projected from A towards D. 



2. During its ascent the point A, and every point of the dia- 

 gonal AE, were also performing a rotary circular motion round 

 the centre of the earth. 



3. The point A would therefore be deflected downward, du- 

 ring its passage towards C,Jrom A below C ; so that D would 

 also be deflected below E, and the entire line AE would be de- 

 flected, or turned downward, beloiu AC. 



4. The rotary motion would therefore have the effect of de- 

 flecting the body below the diagonal AE, at every increment of 



its ascent. 



5. The constant resistance of the atmosphere would, in like 

 mariner, deflect it. 



6. The body would, therefore, be subject, during its ascent, 

 to the action of four forces : 



a, the orbicular force. 



b, the projectile force. 



c, the rotary force. 



d, the resisting force. 



7. jIt the apex, the projectile and rests ting forces having de- 

 Vol'iO. ^0.230. June \8i7. Ee' ilroTjfd 



