xxiv TABLE OF CONTENTS

20. Prime Vertical, Meridian, and Perpendicular from
Zenith to Nadir Intersect at Place Where Observer

Is..............70

21. Vertical Circle Passing through Planet and Place
Where Observer Is (drhmandala); Vertical Circle
Passing through Nonagesimal Point (drkk$epa-
mandala)............70

22. Construction of Wooden Globe Caused To Re-
volve So as To Keep Pace with Revolutions of
Heavenly Bodies .........70

23. Heavenly Bodies Depicted on This; Equinoctial
Sine (Sine of Latitude) Is Base; Sine of Co-
latitude (sahku at Midday of Equinoctial Day)

Is kofi (Perpendicular to Base)...... 70

24. Radius of Day-Circle........ 71

25. Right Ascension of Signs of Zodiac .... 71

26. Earth-Sine Which Measures Increase and De-
crease of Day and Night....... 71

27. Oblique Ascension of Signs of Zodiac .... 72

28. Sahku of Sun (Sine of Altitude on Vertical Circle
Passing through Sun) at Any Given Time . . 72

29. Base of sahku (Distance from Rising and Setting
Line) ............. 73

,30. Amplitude of Sun (agra)....... 73

31. Sine of Altitude of Sun When Crossing Prime
Vertical............ 74

32. Midday sahku and Shadow....... 74

33. Sine of Ecliptic Zenith-Distance (drkk§epajya) . 74

34. Sine of Ecliptic Altitude (drggatijya)} Parallax . 75
35-36. Drkkarman (ak§a and ayana).....76-7

37. Moon Causes Eclipse of Sun; Shadow of Earth
Causes Eclipse of Moon........ 78

38. Time at Which Eclipses Occur...... 78

39. Length of Shadow of Earth ?...... 78

40. Diameter of Earth's Shadow in Orbit of Moon . 79

41. Sthityardha (Half of Time from First to Last
Contact).....'....... 79