Having brought one of the given places to the meridian, bring the index of the hour circle to 12 o’clock; then having brought the other place to the meridian, the number of hours contained between the place the index was first set at, and the place where it now points, is the difference of longitude in time betwixt the two places. Thus the difference of longitude betwixt _Rome_ and _Constantinople_ will be found to be 19 degrees, or 1 hour and a quarter; betwixt _Mexico_ and _Pekin_ in _China_, 240 degrees, or 9⅓ hours. PROB. IV. _Any Place being given to find all those Places that are in the same Latitude with the same Place._ The latitude of any given place being marked upon the meridian, turn the globe round its axis, and all those places that pass under the same mark are in the same latitude with the given place, and have their days and nights of equal lengths. And when any place is brought to the meridian, all the inhabitants that lie under the upper semicircle of it, have their Noon or mid-day at the same point of absolute time exactly. PROB. V. _The day of the Month being given; to find the Sun’s Place in the Ecliptic, and his Declination._ 1. _To find the Sun’s Place_: Look for the day of the month given in the kalendar of months upon the horizon, and right against it you’ll find that sign and degree of the ecliptic which the Sun is in. The Sun’s place being thus found, look for the same in the ecliptic line which is drawn upon the globe, and bring that point to the meridian, then that degree of the meridian, which is directly over the Sun’s place, is the _Declination_ required; which is accordingly either North or South, as the Sun is in the Northern or Southern signs. Thus, _Sun’s Place._ _Declination._ Deg. Min. Deg. Min. _April 23_ ♉ 3 00 12 32 N. _July 31_ ♌ 7 51 18 20 N. _October 26_ ♏ 2 49 12 28 S. _January 20_ ♒ 0 49 20 07 S. PROB. VI. _To rectify the Globe for the Latitude, Zenith, and the Sun’s Place._ 1. _For the Latitude_: If the place be in the Northern hemisphere, raise the arctic Pole above the horizon; but for the South latitude you must raise the antarctic; then move the meridian up and down in the notches, until the degrees of the latitude counted upon the meridian below the Pole, cuts the horizon, and the globe is adjusted to the latitude. 2. _To rectify the Globe for the Zenith_: Having elevated the globe according to the latitude, count the degrees thereof upon the meridian from the equator, towards the elevated Pole, and that point will be the zenith or the vertex of the place; to this point of the meridian fasten the quadrant of altitude, so that the graduated edge thereof may be joined to the said point.