RECENT PROGRESS IN GEODESY. 253 
result is large, but is quite admissible when we consider 
the circumstances. The distance between the stations was 
roughly measured, the direction of the sun’s rays was erro¬ 
neously assumed to be vertical at one of the points, and the 
stations were not quite in the same meridian, a desirable 
condition at this stage of the problem, because in order to 
make the reduction to the meridian a knowledge of the 
size of the earth is requisite, which is precisely the informa¬ 
tion sought. 
Europe gave little thought to this question for fifteen cen¬ 
turies after the birth of Christ. Then comes that remarkable 
measure of Fernel, who by a crude method determined the 
earth’s dimensions with an error of only one-tenth of one 
per cent. For the first time, in Europe, the latitudes of the 
terminal points in the arc were observed and the distance 
between them measured. This determination served to open 
the way for modern work, and from this time on, men ceased 
to look for new methods, but bent their energies towards in¬ 
creasing the accuracy of an existing one which had been 
universally adopted. The greatest stride in this direction 
was made by Snellius, who first introduced triangulation to 
measure distance, and succeeded in reducing the error in 
angular measures to about one minute. Activity was now 
redoubled, and nations began that generous rivalry in the 
prosecution of the work which has been productive of all 
our best information on the subject. Since the year 1600 
the question has been taken up by many civilized nations, 
and the result has simply been to perfect our knowledge and 
give closer and closer approximations to the value sought. 
Two points of interest occur. From the French work it ap¬ 
peared that the earth was flattened at the equator instead of 
at the poles. As this result implied an error in Newton’s 
theory of gravitation, the French Academy sent expeditions 
to Lapland and Peru in order that no doubt might exist. 
Their labors settled the question in favor of an oblate sphe¬ 
roid. 
Passing separate determinations, we come to the work of 
