Hand-Book of the Terrestrial Globe, or Guide to Fitz's New Method of Mounting and Operating Globes; Designed for the Use of Families, Schools, and Academies
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1876 edition. Excerpt: ...to the solar index, or rather with respect to the line of direction of this index, that is actually assumed by the earth's axis relatively to the line joining the centres of the sun and the earth during the annual revolution of the earth around the sun. The solar index describes the passage of the sun between the tropics, marking out the entire circle of the ecliptic in the course of the revolution. The brass circles meantime indicate the changes of length in day, night, and twilight; these changes being more fully illustrated by simply rotating the globe on its axis for different times in the year. The calendar index always points to the day of the year for which the solar index and brass circles are in position. Small knobs projecting from the outer surface of the calendar disk serve to manipulate it. A nut on the under side of the globe-stand may be screwed up, should the disk move too easily. A ring arrangement consisting of a ring called the brass horizon, and a semi-ring called the brass meridian, is employed to represent the horizon and meridian of any given place. It is fitted to position on the globe for any place by adjusting the perforation at the middle of the semi-ring to the place, with the brass meridian passing in the direction of the meridian of the place. The globe being now revolved upon its axis, the solar index describes the daily course of the sun (if the sun rises and sets upon the given day) by moving from side to side of the brass horizon, crossing the brass meridian at the time of noon. When the ring arrangement is adjusted to a given place, the extremity of the brass meridian north of the equator represents the northern point of the horizon, and that south of it the southern. The east and west positions on the brass...
- Paperback | 32 pages
- 189 x 246 x 2mm | 77g
- 27 Jun 2012
- Miami Fl, United States
- Illustrations, black and white