When it is fixed to a wall in an observatory, it is called a mural circle; when mounted with a telescope on an axis and in Y's, in the plane of the meridian, a meridian circle or transit circle; when involving the principle of reflection, like the sextant, a reflecting circle; and when that of repeating an angle several times continuously along the graduated limb, a repeating circle.
The Circles of the Holy Roman Empire, ten in number, were those principalities or provinces which had seats in the German Diet.
Collocations (19)
Azimuth circle , See under Azimuth. Circle of altitude (Astronomy) , a circle parallel to the horizon, having its pole in the zenith; an almucantar.
Circle of curvature , See Osculating circle of a curve (Below).
Circle of latitude (Astronomy) , A great circle perpendicular to the plane of the ecliptic, passing through its poles. A small circle of the sphere whose plane is perpendicular to the axis.
Circles of longitude , lesser circles parallel to the ecliptic, diminishing as they recede from it.
Circle of perpetual apparition , at any given place, the boundary of that space around the elevated pole, within which the stars never set. Its distance from the pole is equal to the latitude of the place.
Circle of perpetual occultation , at any given place, the boundary of the space around the depressed pole, within which the stars never rise.
Circle of the sphere , a circle upon the surface of the sphere, called a great circle when its plane passes through the center of the sphere; in all other cases, a small circle.
Diurnal circle , See under Diurnal. Dress circle , a gallery in a theater, generally the one containing the prominent and more expensive seats.
Druidical circles (Eng. Antiquities) , a popular name for certain ancient inclosures formed by rude stones circularly arranged, as at Stonehenge, near Salisbury.
Family circle , a gallery in a theater, usually one containing inexpensive seats.
Horary circles (Dialing) , the lines on dials which show the hours.
Osculating circle of a curve (Geometry) , the circle which touches the curve at some point in the curve, and close to the point more nearly coincides with the curve than any other circle. This circle is used as a measure of the curvature of the curve at the point, and hence is called circle of curvature.
Pitch circle , See under Pitch. Vertical circle , an azimuth circle.
Voltaic circuit or Voltaic circle , See under Circuit. To square the circle , See under Square.