VOL. XXXIJI.J 1'HILOSOPHICAL TRANSACTIONS. 6l 



manner, the Indian corn has always an equal number of rows of grain on the 

 ear, as 8, 12, 8cc. 



A Dissertation concerning the Figure of the Earth, by the Rev. John Theophilus 

 Desaguliers, LL.D. F.R.S. N° 386, p. 201. 



That tlie earth is of a spherical figure, or nearly such, has been often proved. 

 But as a little variation from a true sphere, besides the irregularity of high hills 

 and deep valleys, does not hinder us from calling the earth a globe; so to deter- 

 mine what that variation may be, since modern philosophers are divided about 

 it, may be a subject not unacceptable. 



M. Cassini says, that the earth is an oblong spheroid, higher at the poles 

 than the eouator, making the axis longer than a diameter of the equator about 

 13 French leagues; which he deduces from comparing his father's measures of 

 the meridian, from Paris to thePyrenean mountains, with those of M. Picard; 

 of which an account may be seen in the Memoirs of the Royal Academy for 

 1713. But having afterwards continued the meridian, which is drawn through 

 France, from Paris to Dunkirk, he still draws consequences to prove the earth 

 an oblong spheroid ; but then he makes the axis exceed the equatorial diameter 

 34 leagues. 



Sir Isaac Newton makes the earth higher at the equator, and consequently 

 flatted towards the poles, reckoning its equatorial diameter 34 English miles 

 longer than the axis; which he proves from the principles of gravity, and the 

 centrifugal force arising from the diurnal rotation of the earth; and to confirm 

 this, mentions several experiments on pendulums, which have been made shorter 

 to swing seconds near the equator, than in greater latitudes. 



These are the two opinions which have divided philosophers, and which Dr. 

 D. proposed to examine. 



M. Cassini, taking the measures abovementioned to be exact enough, not 

 only to determine the magnitude of a degree of the earth, corresponding with 

 a degree of the great circle of the heavens, but also to show the difference in 

 the degrees of the earth; reckoning those that were measured in the south of 

 France, to exceed those towards the north, by a certain number of toises and 

 feet, demonstrates, that if the degrees of the earth are longer towards the 

 equator than the poles, the plane of the meridian must be an ellipse, whose 

 long axis is that of the earth. This he demonstrates in the French Memoirs 

 for the years 1713 and 1718. 



If M. Cassini's measures of terrestrial degrees, decreasing from the equator 

 towards the pole, were grounded on observations liable to no error, he would 

 have fully proved his figure of the earth. But since those measures are not 



