The observatory, which is connected with the university, stands on the summit of the Hill of the Nymphs; like the Academy, it was erected at the expense of a wealthy Greek, Baron **Sina** of Vienna.

Comparing this equation with ux 2 +vy 2 +w2 2 +22G'y2+2v'zx+2W'xy=0, we obtain as the condition for the general equation of the second degree to represent a circle :- (v+w-2u')Ia 2 = (w +u -2v')/b2 = (u+v-2w')lc2 In tangential q, r) co-ordinates the inscribed circle has for its equation(s - a)qr+ (s - b)rp+ (s - c) pq = o, s being equal to 1(a +b +c); an alternative form is qr cot zA+rp cot ZB +pq cot2C =o; Tangential the centre is ap+bq+cr = o, or **sinA** +q sin B+rsinC =o.

Rate at which the plane HOJ revolves about OH, we have **sina** Ccosa ii~~A cosI3iU~, (8)

X **sina** ce.

From this point the line crosses the Cordillera Real through the valley of the San Juan del Oro to Suches Lake, follows the Cololo and Apolobamba ranges to the headwaters of the **Sina** river, and thence down that stream to the Inambari.

The **Sina** river, another tributary of the Bhima, flows through the Nagar and Karjat talukas.

We might note besides that it is quoted in the Book of Adam and Eve, the Apocalypse of Moses, the Apocalypse of Paul, the anonymous work De montibus **Sina** et Sion, the Sibylline Oracles ii.

Hamadan also has the grave of the celebrated physician and philosopher Abu Ali ibn **Sina**, better known as Avicenna (d.