The Astronomical Observatories of Jai Singh c20.s1.19

c20.s1.19

**Trigons or Triplicities.**—The Greek astrologers tried almost every possible combination of the signs of zodiac. The signs being represented by equal spaces on the circumference of the circle, pairs were associated by parallel lines (*Antiscia* of Firmicus, etc.), by diameters, by squares, by hexagons, and by triangles, inscribed in the circle.