442 THE YARD, PENDULUM, AND METRE. 



Schubert however, arbitrarily, and as I think quite inde- 

 fensibly, rejects altogether the result of the French arc, 

 and assigns to the Russian double the weight of the 

 Indian ; a mode of precedure in which he will find, I 

 presume, few to agree with him. A much fairer, indeed 

 the only fair way to treat them, is obviously to ascribe to 

 each of the separate results in taking the mean, a 

 weight proportional to the total extent of the arc, and 

 this gives for the length of the axis 41,708,710-0 feet. 

 Comparing then the final results of the two modes of 

 procedure we find, 



From the former, 41,707,467 feet. 



And from the latter, 41,708,710 



which differ only by 1 243 feet, or less than ^ of a mile 

 so that their mean or 41,708,088-5 f. is in all probability 

 within a furlong, or one part in 64,000 of the truth. 



(25.) From each of the great arcs of Russia and India, 

 M. Schubert then obtains a separate value of the equa- 

 torial or the larger axis of the elliptic meridian to which 

 it belongs; and by a similar treatment of the arc of Peru, 

 which, lying under the equator, is especially favourable 

 for the purpose, he obtains a third value of the equa- 

 torial diameter. The three diameters of the equatorial 

 ellipse thus obtained, with the angles they include at the 

 centre (which are the differences of longitude of the re- 

 spective meridians, and which are as favourably arranged 

 for the purpose as the nature of the case seems to admit), 

 suffice for the determination of the major and minor axis 

 of the equator, regarded as an ellipse, and the longitudes 

 in which they lie, viz. : 



