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Problem 20. To find the time of night. Being out from home, on January 20, I saw the great Dog Star, Sirius, on the ſouthern Meridian, by a quadrant, or compaſs, then bring the Star to the meridian of the Planisphere, and lay the director to the day of the month, and it points to half paſt 10 at night, as was ſought.
Problem 21. To find the time of night on the 15th of May. Being out from home, I observe the Star Atair, due Eaſt, with 11° Altitude.—What is the hour?—Bring the Star to the Prime Vertical, Eaſt, and turn the director to the day of the month, and it points to the hour, 20 minutes before 11 o'clock at night, which is the time required.
Problem 22. Auguſt 1ſt. being out, I obſerved the Sun was due Weſt by the compaſs—What is the hour?—Find the Sun's Place, and bring it to the Prime Vertical, Weſt; then lay the director through it, and it ſhows the time to be 4 minutes before 5, in the afternoon, as was ſought.
Problem 23. What time of day or night, will Cor Leo appear due Eaſt on October 9th? Bring the Star to the Prime Vertical, Eaſtward; lay the director to the day of the month, and it ſhows the time to be 20 minutes before 4, in the morning, for anſwer.
Note! That if, on the contrary of this Problem, the hour be given, then the Planisphere will diſcover
