A Course of Experimental Philosophy - Softcover

This historic book may have numerous typos, missing text or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1745. Not illustrated. Excerpt: ... An Account os the Phenomena explain'd only by the Rotation os the Earth about its Axis. The Earth is here represented by a filver'd Ball of an Inch Diameter, on which are drawn several Circles, a? is done upon the common Globes, viz. the two Polar Circles, the Tropicks, the Æquator, the Ecliptick, and the Parallel of London-, likewise 24 Meridians, one of which grav'd in thicker than the rest, represents the Meridian of London, which Place is express'd by a strong Spot or Point in 51 4- Degrees of North Latitude. From a rais'd and bent Wire-Arch skg hangs a Plate like a Crescent, wanting 47 Degrees of 3 whole Circle at Bottom, that it may not fall foul upon the Axis of the Earth. The Plane of this Plate does always pass through the Center of the Earth, and facing the Sun, is always perpendicular to a Ray coming from the Sun to the Earth, and consequently divides the enlighten'd from the darken'd Part of the Earth: Therefore I call it a Solar Horizon; and W, E mark'd upon it, shew the West and the East. In a Line suppos'd to be drawn from the Center of the Sun to the Center of the Earth, is fix'd, upon two Props, the Solar Ray or Wire m /, to shew on what Part of the Earth the Sun shines perpendicularly at any Day, Hour, or Minute of the whole Year. There is an Index b, which shews the Place of the Earth on the Ecliptick, and likewise opposite to it, there is another Index (with a little Sun grav'd upon it) to shew the Sun's Place in the opposite Part of the Ecliptick. Taking hold of the blue Plate, the Earth must be brought to the first Degree of Capricorn, which will be shewn by its Index then the Axis of the Earth (always making an Angle of 664 Degrees, with the Plane of the Ecliptick) must be so set, that the North Pole may be towards the Sun, and a Plan...