Modern Methods in Horology
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1904 edition. Excerpt: ...India ink and a bow pen. The triangles and protractor are more convenient if made of celluloid, as they are transparent and we can use them to better advantage. We can get a triangle (right angle) and protragctor combined, which is very satisfactory. Figure 1 shows the drawing board A. and the various instruments one should have to start; the better the quality of the instruments, the better the work may be expected, but to begin with, cheap ones may be used, although they are not so accurate. On the drawing board is shown the following: B. T square. C. Right angle, triangle and protractor combined. D. 30-60-90 triangle. E. Dividers. F. Pen and pencil dividers. G. Hard pencil. I--I. Pencil eraser. I. Paper with thumbtack in each corner. J. Metric Ruler. It will be necessary for us to understand the geometrical terms used in order to follow the drawing intelligently. In order that the reader may become more familiar with the terms, they are defined as follows: 1. A point has neither length, breadth or thickness, and shows position only. 2. A line has but one dimension--length. 3. A straight line is one that does not change. its direction throughout its length. 4. A curved line changes its direction at every point. 5. A broken line is made of several straight lines, having dilferent directions. 6. Parallel lines are the same distance from each other at all points. 7. A line is perpendicular to another when the angles formed by it are right angles. 8. An angle is the opening between two lines that meet; the vertex is the point where they meet. 9. If a perpendicular line is drawn from the center of a straight line, two right angles will be formed, each containing 90. 10. An acute angle is less than a right angle. 11. An obtuse angle is...
- Paperback | 50 pages
- 189 x 246 x 3mm | 109g
- 13 Sep 2013
- Illustrations, black and white