43& EXPLANATION OF THE PRINCIPAL TERMS

T.

Taurus, the Bull, a zodiacal constellation, consistingof one hundred and nine stars.

Telescopic Stars, those stars which are only discover-able by means of a telescope.

Temperate Zones, those parts of the earth containedbetween the tropics and polar circle.

Theory, any doctrine which terminates in speculation,without considering the practical uses and applicationof it.

Torrid Zone, that part of the earth which is containedbetween the two tropics.

Transit, is the pasting of onp celestial body before ano-ther, so as to render any part of it invisible.

Trigonus Major, the Great Triangle, a northernconstellation, consisting of ten stars.

Trigonus Minor, the Little Triangle, a northernconstellation, consisting of five stars.

Trine, an aspect of the planets, when they are a hun-dred and twenty degrees distant from each other; andin an Ephemeris is denoted by A-

Tropics, two small circles of the sphere which are pa-rallel to the equator, and twenty-three degrees twenty-eight minutes distant from it.

Twilight, is that faint light which we perceive beforethe rising of the fun, and after his setting, and is occa-sioned by the refraction of the earth’s atmosphere.

V.

Vector Radius, a line supposed to be drawn from anyplanet to the sun, which moving with the planet, de-scribes equal areas in equal times.

5 Venus,