2 The Illuminated Disc of the Moon. (January, 
should have the following as the altitude of the points 10° 
distant from each other, viz. :— 
Bees 
14° 0 
20, AZ, 
By es 
32° 48" 
37, 46° 
41° 38° 
44 8 
45/50 
Thus, in the following figure, let M R represent a portion 
of the meridian, E Ww the horizon, M the south point of the 
horizon, E the east and w the west points. The arc, 
E, a, b,c, R, is the equinoctial, being that quadrant between 
the east point on the horizon, and the meridian, a, b,c, &c., 
represent arcs of Io’. 
IMG 2% 
E M Ww 
The point a will be 7° 3’ above the horizon, 6 14° above 
the horizon, c 20° 42’, and soon. In the same manner the 
curve from R to w may be traced out during the whole 
quadrant. 
Let us suppose that there are three stars, a, 0, c, situated 
on the equino¢tial, and in the positions indicated by a, }, 
andc. Also that another star was situated at 0, also on 
the equinoctial. 
To an observer at the North Pole these four stars would 
appear on the horizon, and a straight line joining a and ¢ 
would pass through 0, and if produced would pass through 
the star o. To anobserver at the equator, on the meridian, 
of which R M is a part, and so situated that R was in the 
zenith, the three stars, a, b, c, would also appear in the same 
straight line, and this straight line if produced would pass 
through o. 
