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and Perpetual Occultation, are different parts, or portions of the celeſtial ſphere in all the different Latitudes upon this Globe; and in this parallel, the Circle of Perpetual Apparition is all that part of the celeſtial ſphere round the North Pole, that never ſets below the Horizon, being from the parallel of 38° 28' declination Northward, and is always equal to the compliment of the Latitude; all the Stars within this Parallel revolve round and round the Pole, but never diſappear, nor deſcend lower than the Northern part of the Horizon, and theſe are ſometimes called Circum-Polar Stars, and you will ſee them, with their names in the Planisphere, by turning the Index round about;—by the same cause, the Circles of Perpetual Occultation, is, all thoſe Stars, near, and round the South Pole, which never riſe above the Southern part of our Horizon, from 38° 28' Declination Southward, to the South Pole.
But, this ſubject will be better illustrated, and rendered apparent, by the ſolution of the following Problems with the Planisphere.
Problem 1. The day of the month, and hour of the day given, to rectify the Planisphere for uſe, ſuppoſe July 5th, at 4 hours, 36 minutes, P. M.?
Find the day of the month in the outermoſt circle, and bring the hour and minute on the index thereto, and it is done. This Problem is very ſhort, and ſolved in an inſtant; but its effects are very extenſive and
