18« 



DIURNAfc MOTION OF THE EARTH, 



velocities of any two opposite points of the equator are to 

 each other, as 



s 



1 + 



64-4 — A L * 

 2AL~AL* 



is to 



tK 



04'4 -— IS iM* 



velocities at the 

 equator. 



Effscts on gra- 

 vitation, 



Difference of From this formula I have deduced, that the velocity of 

 any point of the equator at noon is to the velocity of the 

 game point at midnight, as 36*90 to 3502, or as T053 to 1 *. 

 In like manner I have found, that the velocity at 1 o'clock 

 P. M. is to the velocity at 1 A. M. as 248'9 to 241*4, or at 

 1-032 to 1. 



I afterward calculate the effects, which this d'hfference in 

 the velocities of two opposite points in the same parallel of 

 latitude would produce on the force of gravity at the sur- 

 face of the Earth, and I rind, that, under the equator, bo- 

 dies lose at noon a 9375th of their weight. I then demon- 

 ani come- strate, that the effect, which this difference in the gravity of 

 sea" &c. bodies produces upon the matter and fluids on the surface 



of the globe is 306 times greater than f the effect produced 

 by the attraction of the moon, and 1372 times greater than 

 any effect produced by the sun. • 



Application to This principle I have employed to explain the tides, the 

 phenomena, tra( j e winds, and the phenomena of falling stones J. My 

 theory necessarily leads into researches of too great length, 

 to find a place in this brief analysis : I confine myseli'there- 

 fore, Sir, to request your serious examination of the princi- 

 ple of cyeloidal motion, which I ascribe to every point of the 

 surface of the globe, and the effects which this motion must 

 produce on bodies at its surface. Your ideas on this sub- 

 ject will highly obiige me. 



I have the honour to be, 

 Sir, 

 Your very obedient, and very humble servant, 



JOHN WOOD. 



* In tlic work itself, which is now before me, there is a list of er- 

 rata, which BOttkefe these numbers as 37\8 to 3<5p2, or as 1034 to 1. C. 



f It should be " 3"6 tunes as '.-real as. 1 ' C. 



J Prof. Wood supposes the stones, that fall from the atmosphere, to 

 |>e projected into it from volcanoes: and that, as the point from which 

 they are thrown has its votary velocity increased or diminished, 

 white the stones retain that impressed on them at the time of tlwir 

 projection, they must consequently reach the Earth at a greater or less 

 Obtance east or west of the volcano. C. 



Method 



Meteoric 

 stones. 



