42 The figure NBSWN, which looks like a fish has been called a “iिsh figure Also see my notes on MBh, i. 1, 2. ': A rule for finding the latitude and colatitude of a place from the eguin0ctial midday shadow of the grnommon : 2-3. By whatever results as the suare root of the sum of (1) the sपृuare of the eguin0ctial midday shadow of the gnommon, which is erected on level ground at the intersection of the direc tion-lines and wh0se perpendicularity has been tested, and (ii) the square of the gnormon, divide the radius (severally) multipli ed by the gnommon and the (eguinoctial midday) shadow : the results are the Rsines of the colatitude and the latitude. That is, if R be the radius of the celestial sphere, g the length.of the. gion0n, and s the length of the equinoctial midday shadow, } the latitude of the place, and C(=90- ) the colatitude, then s11
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= [ cr. Iा x R Fig. 4 Fig. 4 is the celestial sphere for a place in latitude . SENW is the hori टon, S, E, N and W being the south, east, north and west points; 2८ is the i.e., at the centre of the circle drawn on the ground. C. MBh, i. 4-50(i-iii). See stam (1) 1. (2)
