GLOBE. 
globe round again, and note the two points 
of the ecliptic passing under that degree 
of the meridian. Lastly, by the wooden 
horizon, find on what days the sun is in 
those two points of the ecliptic; and on 
these days he will be vertical to the given 
place. 
12. “ To find those places in the torrid 
zone to which the sun is vertical on a given 
day.” Having found the sun's place in the 
ecliptic, as in the eighth problem, turn the 
globe to bring the same point of the ecliptic 
on the globe to the meridian ; then again 
turn the globe round, and note all the 
places which pass under that point of the 
meridian ; which will be the places sought. 
After the same manner may be found 
what people are ascii for any given day. 
And also to’ what place of the earth, the 
moon, or any other planet, is vertical on a 
given day : finding the place of the planet 
on the globe by means of its right ascen- 
sion and declination, like finding a place 
from its longitude and latitude given. 
13. “To rectify the globe for the latitude 
of any place. By sliding the brass meri- 
dian in its groove, elevate the pole as far 
above the horizon as is equal to the latitude 
of the place; so for London, raise the 
north pole fifty-one and a half degrees 
above the wooden horizon: then turn the 
globe on its axis till the place, as London, 
come to the meridian, and there set the 
index to twelve at noon. Then is the 
place exactly on the vertex, or top point of 
the globe, at ninety degrees every way 
round from the wooden horizon, which re- 
presents the horizon of the place. And if 
the frame of the globe be turned about till 
the compass needle point to twenty-two 
and a half degrees, or two points west of 
the north point (because the variation of the 
magnetic needle is nearly twenty-two and 
a half degrees west), so shall the globe 
then stand in the exact position of the 
earth, with its axis pointing to the north 
pole. 
14. “ To find the length of the day or 
night, or the sun’s rising or setting, in any 
latitude ; having the day of the month 
given.” Rectify the globe for the latitude 
of the place ; then bring the sun’s place on 
the globe to the meridian, and set the index 
to twelve at noon, or the upper twelve, 
and then the globe is in the proper posi- 
tion fqr noon-day. Next turn the globe 
about towards the east till the sun’s place 
come just to the wooden horizon, and the 
index will then point to the hour of sun- 
rise ; also turn the globe as far to the west 
side, or till the sun’s place come just to the 
horizon on the west side, and then the in- 
dex will point to the hour of sun-set. These 
being now known, double the hour of sett- 
ing will be the length of the day, and 
double the rising will be the length of the 
night. And thus also may the length of 
the longest day, or the shortest day, be 
found for any latitude. 
15. “ To find the beginning and end of 
twilight on any day of the year, for any 
latitude.” It is twilight all the time from 
sun-set till the sun is eighteen degrees be- 
low the horizon, and the same in the morn- 
ing from the time the sun is eighteen de- 
grees below the horizon till the moment iof 
his rise. Therefore, rectify the globe for 
the latitude of the place, and for noon by 
setting the index to twelve, and screw on 
the quadrant of altitude. Then take the 
point of the ecliptic opposite the sun’s 
place, and turn the globe on its axis west- 
ward, as also the quadrant of altitude, till 
that point cut this quadrant in the eigh- 
teenth degree below the horizon, then the 
index will shew the time of dawning in the 
morning ; next turn the globe and quadrant 
of altitude towards the east, till the said 
point opposite the sun’s place meet this 
quadrant in the same eighteenth degree, and 
then the index will shew the time when 
twilight ends in the evening. 
16. “ At any given day, and hour of the 
day, to find all those places on the globe 
where the sun then rises, or sets, as also 
where it is noon-day, where it is day-light, 
and where it is in darkness.” Find what 
place the sun is vertical to, at that time ; 
and elevate the globe according to the 
latitude of that place, and bring the place 
also to the meridian ; in which state it will 
also be in the zenith of the globe. Then 
is all the upper hemisphere, above the 
wooden horizon, enlightened, or in day 
light; while all the lower one, below the 
horizon, is in darkness, or night : those 
places by the edge of the meridian, in the 
upper hemisphere, have noon-day, or twelve 
o’clock; and those by the meridian below, 
have it midnight : lastly, all those places 
by the eastern side of the horizon, have 
the sun just setting, and those by the 
western horizon have him just rising. 
Hence, as in the middle of a lunar eclipse 
the moon is in that degree of the ecliptic 
opposite to the sun’s place ; by the pre- 
sent problem it may be shewn what places 
of the earth then see the middle of the 
