Here it will be convenient to introduce one or two technical terms: we generally define a star’s place by giving, as one ordinate, its distance in degrees from the equator: this distance is called its _declination_. Further, we generally define points on the horizon by dividing its whole circumference into 360°, so that we can have _azimuths_ up to 90° from the north and south points to the east and west points. We also have _amplitudes_ from the east and west points towards the north and south points. We can say, then, that a star of a certain declination, or the sun when it occupies that declination, will rise or set at such an azimuth, or at such an amplitude. This will apply to both north and south declinations. Then supposing the azimuth to be 39° in the N.E. quadrant, it is written N. 39° E. For the other quadrants we have N. 39° W., S. 39° E., and S. 39° W., respectively. The following table gives the amplitudes of rising or setting (north or south) of celestial bodies having declinations from 0° to 64°, at Thebes and Stonehenge respectively. AMPLITUDES AT THEBES AND STONEHENGE. ------------+-------------------- | Amplitude. Declination.+-------+----------- |Thebes.|Stonehenge. ------------+-------+----------- 0° | 0° 0′| 0° 0′ 1 | 1 7 | 1 36 2 | 2 13 | 3 11 3 | 3 20 | 4 46 4 | 4 26 | 6 22 5 | 5 33 | 7 58 6 | 6 40 | 9 34 7 | 7 47 | 11 10 8 | 8 53 | 12 47 9 | 9 59 | 14 23 10 | 11 6 | 16 1 11 | 12 13 | 17 39 12 | 13 20 | 19 18 13 | 14 27 | 20 57 14 | 15 34 | 22 36 15 | 16 41 | 24 17 16 | 17 49 | 25 58 17 | 18 56 | 27 45 18 | 20 3 | 29 24 19 | 21 10 | 31 10 20 | 22 17 | 32 55 21 | 23 25 | 34 43 22 | 24 33 | 36 32 23 | 25 41 | 38 23 24 | 26 49 | 40 16 25 | 27 58 | 42 11 26 | 29 6 | 44 10 27 | 30 15 | 46 10 28 | 31 23 | 48 15 29 | 32 32 | 50 22 30 | 33 41 | 52 36 31 | 34 51 | 54 55 32 | 36 1 | 57 21 33 | 37 11 | 59 56 34 | 38 21 | 62 42 35 | 39 31 | 65 44 36 | 40 42 | 69 4 37 | 41 53 | 73 0 38 | 43 5 | 78 4 39 | 44 17 | 90 0 40 | 45 30 | 41 | 46 43 | 42 | 47 56 | 43 | 49 10 | 44 | 50 25 | 45 | 51 41 | 46 | 52 57 | 47 | 54 14 | 48 | 55 32 | 49 | 56 51 | 50 | 58 12 | 51 | 59 34 | 52 | 60 58 | 53 | 62 23 | 54 | 63 51 | 55 | 65 21 | 56 | 66 54 | 57 | 68 31 | 58 | 70 12 |