370. Make a Scale of any convenient length (six inches at least) as _AC_, and divide it into as many equal parts as the semi-diameter of the Earth’s Disc contains minutes, which in this construction of the Eclipse for _London_ in _April 1764_, is 54 minutes and 57 seconds; but as it wants only 3ʺ of 55ʹ the Scale may be divided into 55 equal parts, as in the Figure. Then, with the whole length of the Scale as a Radius, setting one foot of your Compasses in _C_ as a center, describe the Semi-circle _AMB_ for the northern Hemisphere or Semi-disc of the Earth, as seen from the Sun at that time. Had the Place for which the Construction is made been in South Latitude, this Semi-circle would have been the Southern Hemisphere of the Earth’s Disc. [Sidenote: Axis of the Ecliptic.] 371. Upon the center _C_ raise the straight line _CH_ for the Axis of the Ecliptic, perpendicular to _ACB_. [Sidenote: North Pole of the Earth.] 372. Make a line of Chords to the Radius _AC_, and taking from thence the Chord of 23-1/2 Degrees, set it off from _H_ to _g_ and to _h_, on the periphery of the Semi-disc; and draw the straight line _gNh_, in which the North Pole of the Disc is always found. 373. While the Sun is in Aries, Taurus, Gemini, Cancer, Leo, and Virgo, the North Pole of the Disc is illuminated; but while the Sun is in Libra, Scorpio, Sagittary, Capricorn, and Aquarius, the North Pole is hid in the obscure part behind the Disc. 374. And, whilst the Sun is in Capricorn, Aquarius, Pisces, Aries, Taurus, and Gemini, the Earth’s Axis _CP_ lies to the right hand of the Axis of the Ecliptic _CH_ as seen from the Sun, and to the left hand while the Sun is in the other six Signs. [Sidenote: Earth’s Axis. Universal Meridian.] 375. Make a line of Sines equal in length to _Ng_ or _Nh_, and take off with your Compasses from it the Sine of the Sun’s distance from the nearest Solstice, which in the present case is 77° 51ʹ § 367, and set that distance to the right hand, from _N_ to _P_, on the line _gNh_, because the Sun being in Aries § 359, the Earth’s Axis lies to the right hand of the Axis of the Ecliptic § 374: then draw the straight line _C_XII_P_, for the Earth’s Axis and the Universal Meridian; of both which _P_ is the North Pole. [Sidenote: Path of a given Place on the Disc as seen from the Sun.]