Prob. XI. The Day of the Month being given, to find those places on the globe where the Sun will be Vertical, or in the Zenith, that day.
Having found the Sun’s place in the ecliptic, bring the same to the meridian, and note the degree over it; then turning the globe round, all places that pass under that degree will have the Sun vertical that day.
Prob. XII. A place being given in the Torrid Zone, to find those two Days in which the Sun shall be Vertical to the same.
Bring the given place to the meridian, and mark what degree of latitude is exactly over it; then turning the globe about its axis, those two points of the ecliptic, which pass exactly under the said mark, are the Sun’s place; against which, upon the wooden horizon, you’ll have the days required.
Prob. XIII. To find where the Sun is Vertical at any given time assigned; or the Day of the Month and the Hour at any Place (suppose London) being given, to find in what place the Sun is Vertical at that very time.
Having found the Sun’s declination, and brought the first place (London) to the meridian, set the index to the given hour, then turn the globe about until the index points to XII at noon; which being done, that place upon the globe which stands under the point of the Sun’s declination upon the meridian, has the Sun that moment in the Zenith.