Page:Description and Use of a New Celestial Planisphere.pdf/19

14 When the reader has tudied and learnt the Principle and Contruction of the Planisphere, which is easy to accomplih, he will find it is adapted, in the mot eay and ready manner, for olving all the Problems to which it is applied, and I may venture to ay, far more o than the Celetial Globe, it being inconvenient on the Globe to apply, and work the Hour Circle and the days of the months together, and to concentrate the Hour Circle and the Ecliptic is impoible; but, on this Planisphere, the Days of the Months and the Degrees of the Ecliptic are adjuted together, by which means the Day of the Month being given, is the ame as the Sun's place in the Ecliptic, or the contrary, o that thee may become ynonymous terms in the Planisphere, and as the Hour Circle on the Index turns concentrical with the Circle of Months, and jut within it, o mot of the Problems are olved at one remove of the Index, and the anwer appears in an intant, by inpection.

Having now decribed, and prepared the Planisphere for ue, I hall next explain the motions of the Terraqueous Globe on which we live: and firt, according to the true, or Copernican Sytem of the Univere, this Globe is a Planet, revolving round the Sun in an orbit omewhat elliptical, and in the pace of 365 days, 5 hours, and 49 minutes, being accompanied with the Moon, and hath the Sun at ret in the center of its orb.–Now, conceive at a vat distance, without this ytem, the phere of the fixed Stars; and then imagine that on this, or ome one day, the Sun appears to a