2^ Mr Watts o?i the Ell\/ptidty of the Earth. 
■ This value differs very little from — ^ , the compression 
<51 
which M, Biot has deduced from the observations that have 
been made upon the different points of the French meridian, 
from Formentera to Dunkirk. But by correcting the latitudes 
of Formentera and Clermont, which latitudes are stated to be 
88° 39' 46", and 46® 48^ 4" respectively, see “ Astronomie Phy- 
sique^'‘ par Biot, tom. hi. p. 164., instead of 38® 39' 57" 1, and 
45® 46' 44", we shall deduce from the same observations the 
compression , which, however, is not materially differ- 
ent from the compression computed by M. Biot himself. 
Hence it appears, that the mean compression thus deduced 
from the observations which have been made on the lengths of 
the seconds’ pendulum, at different points of the terrestrial me- 
ridian, from Formentera to Unst, comprising an arc of the me- 
ridian equal to S2® 5' 4S", or nearly one-fourth part of the ter- 
restrial quadraqt, amounts to 
It may not be improper to remark, that the compression 
^97 ^05 ^ two inequalities in the lu- 
nar motions ; the first, depending on the longitude of the moon’s 
node, and amounting to 20,987 decimal seconds, according to 
M. Burg, corresponds with the oblateness 
1 
305,05 * 
The second, depending on the sine of the true longitude of 
the moon, and resulting from a nutation in the lunar orbit, 
produced by the action of the terrestrial spheroid, and corre- 
sponding with that which the moon produces on the terrestrial 
equator, in such a manner, that one of these nutations is the re- 
action of the other ; so that if all the particles of the earth and 
moon were rigidly connected together by inflexible straight 
lines, without mass, the entire system would be in equilibrio 
round the centre of gravity of the earth, in virtue of the forces 
which produce these two nutations. M. Burg has determined 
the coefficient of this inequality by a great number of observa^ 
tions, and found it equal to — 24,6914 decimal seconds; this 
