MADE USE OF IN ASTRONOMY, t „ 423

Gregorian Y ear, so called from Pope Gregory XIII.who reformed the calendar in the year 1582; whichreformation was not used in England till 1752.

Greyhounds, a northern constellation consisting oftwenty-four stars.

Grus, the Crane, a southern constellation composed offourteen stars.

H.

Hexiacal rising of a star, is when it emerges fromthe fun’s rays, and appears above the horizon beforehim in the morning.

Heliacal setting of a star, is when it is so hid in thefun’s beams, as not to be seen above the horizon afterhim in the evening.

Heliocentric place of a planet, is that in which itwould appear to a spectator placed in the fun.

Hemisphere, the half of a globe or sphere when it iscut through its center in the plane of one of its greatcircles.

Hercules, a northern constellation composed of ninety-two stars.

Hesperus, a name given to the planet Venus when sheappears in the evening.

Heteroscii, a name given to the inhabitants of the tem-perate zones, because their shadows at noon always fallone way.

fdiRUNDO, the Swallow, a southern constellation com-posed of eleven stars.

Horizon, (Sensible,) a circle which separates the visiblehemisphere from the invisible one, or that which is theboundary of our sight.

E e 4. Horizon,