THE YARD, PENDULUM, AND METRE. 45I 



Longitude of the vertex of the longer axis= 13 58' 30' 

 east or 11 35' 15" E. of Paris) whence it is easy to 

 conckide as follov/s : 



Diameter of equator in the longitude of Paris. ..41, 852, 695 feet. 

 Elliplicily of the Paris meridian tjVit say -g-l^ 



(35.) Calculating now the quadrant from this ellip- 

 ticity, and from Captain Clarke's polar axis, we find it 

 32,814,116 feet, which exceeds ten million metres by 

 5124 feet, being in excess of that above found (4008) 

 by 1 1 16 feet; and corresponding to an aliquot error of 

 one part in 6404, or on the metre itself to one 163d part 

 of an inch. The aliquot error in our "geometrical 

 yard " is also somewhat increased by the adoption of 

 this polar axis, viz., to one part in 52,310, or to about 

 one 1453d part of an inch on the yard. 



(36.) As this memoir of Captain Clarke contains by far 

 the most complete and comprehensive discussion which 

 the subject of the earth's figure has yet received, and 

 m.ust be held as the ultimatum of what scientific calcula- 

 tion is as yet enabled to exhibit as to its true dimen- 

 sions and form this conclusion will of course be con- 

 sidered to supersede that arrived at in the foregoing 

 pages. 



COLLINGWOOD, Oct. II, 1 863. 



P.S. Some slight subsequent corrections made by Capt. 

 Clarke in his calculations, founded on data quite 

 recently published, make the polar axis approximate 

 still more nearly to 500,500,000 inches. 



