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.

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.

Of the socalled Arabian philosophers of the East, al-Farabi, Ibn-**Sina** and al-Ghazali were natives of Khorasan, Bokhara and the outlying provinces of north-eastern Persia; whilst al-Kindi, the earliest of them, sprang from Basra, on the Persian Gulf, on the debatable ground between the Semite and the Aryan.

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.