In a system of plane co-ordinates (see Co-ordinates) the distance of any point from the axis of ordinates measured parallel to the axis of abscissas. In the cut the abscissa of the point a is the line or distance a c. Fig. 1. AXES OF CO-ORDINATES

A great circle, whose plane passes through the zenith or point of the heavens directly overhead; any great circle in whose plane the vertical at the point of observation is included. Each celestial body has or determines an azimuth circle.

The angle between the plane of the meridian and the plane of an azimuth circle, q. v.

In a system of rectilinear right angle co-ordinates, the vertical axis. (See Co-ordinates.) Synonym–Axis of Y.

In a system of rectilinear, or right angle co-ordinates, the horizontal axis. (See Co-ordinates.) Synonym–Axis of X.

The electric axis of a pyroelectric crystal, such as a tourmaline crystal; the line connecting the points of greatest pyroelectric excitability.

Abbreviation for American Wire Gauge, q. v.

The north pole of the magnet is thus called sometimes in France; the austral pole of a magnet is the one which points towards the north polar regions As unlike magnetic poles attract each other, it is but rational to call the north-seeking pole of the magnet the south or Austral Pole. In the same [...]

A luminous display seen in the northern heavens in the northern hemisphere, where it is the Aurora Borealis, and seen in the southern heavens in the southern hemisphere, where it is called Aurora Australis, or indifferently for either, the Aurora Polaris. It takes the form of pale luminous bands, rays and curtains varying in color. [...]

The blast of air produced at highly electrified points.