ECL 
and nights were equal. Hence the equator 
came, to be called the equinoctial line, and 
the points in which it cuts the ecliptic were 
called the equinoctial points, and the sun 
was then said to be in the equinoxes. One 
of these was called the vernal, and the 
other the autumnal equinox. See Equi- 
noxes. 
Ecliptic, obliquity of, is the angle 
which its plane makes rvith that of the equi- 
noctial. The inclination of the equator 
to the ecliptic is measured by the arch of 
a great circle intercepted between their 
poles, which was taken with very great 
accuracy by Dr. Maskelyne, in the year 
1769, and found to be 23" 28' 10 ", or 
23" 46944. It was formerly found by Dr. 
Bradley to be 23° 28' 30", who supposed 
that there was a gradual approach of the 
ecliptic to the equinoctial at the rate of 1' 
in 100 years. The mean obliquity of the 
ecliptic, is augmented by '9'', when the 
moon’s ascending node is in the vernal equi- 
nox. It is on the contrary, diminished 9 ", 
when the. node is in the autumnal equinox, 
and it is equal to the mean when the 
node is in the colure of the solstices. This 
change of the inclination of the earth’s 
axis to the plane of the elliptic was called 
the nutation of the axis by Sir Isaac New- 
ton. 
Dr. Bradley discovered a general and 
periodical motion in all the stars, which 
alter a little their relative situations. To 
form an idea of this motion, let us suppose 
that each star describes annually a small 
circumference parallel to the ecliptic, whose 
centre is the mean position of the star, and 
whose diameter, as seen from the earth, 
subtends an angle of about 40'" ; and that it 
was in that circumference as the sun in its 
orbit, but so that the sun always precedes it 
by 90“. This circumference, projected 
upon the surface of the celestial sphere, ap- 
pears under the form of an ellipse, more or 
less flattened according to the height of 
the star above the equator, the smaller axis 
of the ellipse being to the greater axis as 
the sine of that height to the radius. These 
periodical movements of the stars have re- 
ceived the name of aberrations of the fixed 
stars. See Aberration. 
Ecliptic, in geography, a great circle 
on the terrestrial globe, not only answering 
to, but falling within the plane of the ce- 
lestial ecliptic. See Globes, use of. 
ECLOGUE, in poetry, a kind of pasto- 
ral composition, or a small elegant poem, in 
a natural simple style. 
ECO 
The eclogue, in its primary intention, » 
the same thing with the idyllium, but cus- 
tom has made some difference between 
them, and appropriated the name of eclogue 
to pieces wherein shepherds are introduced, 
and idyllium to those written tike eclogues, 
but witliout any shepherds in them. The 
eclogue then is properly an image of pasto- 
ral life, upon which account the matter is 
low, and its genius humble. Its business is 
to describe the loves, sports, piques, jealou- 
sies, intrigues, and other adventures of 
shepherds; so that its character must be 
simple, the wit easy, and the expression 
familiar. Then the true character of the 
eclogue is simplicity and modesty ; its figures 
are neat, the passions tender, the motions 
easy, and tliough sometimes it may have lit- 
tle transports and despairs, yet it never 
rises so high as to be fierce or violent. Its 
narrations are short, descriptions little, the 
thoughts ingenuous, the manners innocent, 
the language pure, the verse flowing, the 
expressions plain, and all the discourse 
natural. 
ECONOMY, political. .Political eco- 
nomy is the science which treats of the 
wealth of nations. Its object is to ascer- 
tain, in the first place, wherein wealth con- 
sists, and then to explain the causes of its 
production, and the principles on which it 
is distributed through the different ordei's of 
society. It likewise endeavours to point 
out the tendency which any political regu- 
lations may have to favour or to injure the 
productions or most advantageous distribu- 
tion of wealth. Such is its peculiar object, 
and consequently though writers on politi- 
cal economy may frequently treat on the 
more important topics of national security, 
freedom and happiness, these are then pass- 
ing the strict limits of their science. 
Political economy, in some of its branches, 
has engaged the attention of speculative 
men in all ages ; but it is only in very re- 
cent times that the truths it exhibits have 
been collected, arranged, and demonstrated 
with such precision, as to entitle it to the 
name and dignity of a science. 
The writers on political economy may be 
arranged in two great classes ; the fi)riner 
composed of those who regard commerce, 
and the latter of those who regard agricul- 
ture as the principal source of national 
wealth. Almost all the older writers be- 
long to the former class. The most consi- 
derable English writers of this class are 
Dr. d’Avenant and Sir John Stewart, and 
their principles are interwoven in the elab»;^ 
