MCZ PRINCE EDWARD 1851 Duration ---------lb. 44m. A very small portion only of the Sun's Northern limb will be obscured. This Eclipse will be total and central in the northern; part of British America, , Greenland, Iceland/ Norway and . Venus wiU be the Morning Star until Octr. 11. After" which she will be the Evening Star to the end of Ihe year. Mars will be the Morning Star during the year. Jupiter will be the Morning Star until April !>, then the; Evening Star until Octr. 22, thence the Morning Star to the; close of the year. • Saturn will be the Evening Star until April 13, then the Morning Star until Octr. 22, after which the Evening Star. EXPLANATION OF THE CALENDAR PAGE8. LIFT HAND PAGE. Column. 1 *& 2.—Contain the days of the month and of the week. 3 & 4.—The rising and selling in mean time of the highest point, or of the upper limb of the Sun, corrected for refraction. 5.—Days length in hours and minutes. 6.—The Equation of Time (or quantity by which Ihe Sun is tlote or fast of the clock) at noon, apparent time (not mean i at Greenwich . The interval of time between the Sun being; on the Meridian or Southing, on one day and his being on the Meridian or Southing on the next day, is not always the same; and therefore, solar days are not equal in dura tion; about one-half are a little more, and about one- half are a little less than 24 hours. A clock regu¬ lated by the Sun, or the Sun-dial, would need frequent adjustment; to avoid this, an imaginary sun is supposed to move, so that the interval of time between its consecutive* passages over the meridian is always the same, vix , 24 hours; such a time represents a mean solar day, and it is the average of all (he apparent solar days in a year. Thej difference of time between the imaginary Sur. and the true! Sun passing the Meridian, is called the " Equation of i Time," the amount of which at noon on every day i » inserted in this column. There are only 4 days in the year when apparent and meantime are the same, or ihe Equation; of time is nothing. In this year these days are April 16,' June 16, Sept. 1, and Deer. 25. By the assistance of the numbers in this column, a clock can be set by a Sun-dial as follows;—When fast is placed above the number opposite to Ihe day, then the clock' ought to be set fast on the time shown by the Sun-dial—\ and when slow is above the number, the clock ought to bei set so much slower. Example :—When the Sun shows, noon on the Sun dial on June I, and July 1, what are the .