Problem 28. To find the time of the Sun's rising and set-
ting, and the length of the day and night at any place,
Problem 29. The length of the day at any place being giv
en, to find the Sun's declination, and the day of the month, 208
Problem 30. To find the length of the longest day at any
place in the north frigid Zone,
Problem 31. To find the length of the longest night at any
place in the north frigid Zone,
Problem 32. To find the number of days which the Sun rises
and sets at any place in the north frigid Zone,
Problem 33. To find in what degree of north latitude, on any
day between the 21st of March and the 21st of June, or in
what degree of south latitude, on any day between the 23d
of September and the 23d of December, the Sun begins to
shine constantly without setting; and also in what latitude
in the opposite hemisphere he begins to be totally absent,
Problem 34. Any number of days not exceeding 182, being
given, to find the parallel of north latitude in which the Sun
does not set for that time,