# A Manual of Topographical Drawing

### What people are saying -Write a review

We haven't found any reviews in the usual places.

### Popular passages

Page 107 - The angle which a line makes with a plane is the angle which it makes with its projection on the plane.
Page 103 - BCD (Fig. 18) be the given square. It is required to construct a square which shall be to ABCD as 2 is to 5. Upon the side AB as a diameter describe the semicircle AFB, and divide the line AB into five equal parts.
Page 73 - In a slope of } this rule will always make the breadth of the shading lines twice that of the white space contained between them. To represent declivities by the vertical system of shading a considerable amount of practice is required. This practice should be commenced by drawing repeatedly the scale...
Page 63 - ... upon the principle of vertical illumination, in which the maximum light is reflected upwards to the eye by a horizontal surface, and a minimum by a surface inclined 45° to the horizon. The latter, being the steepest slope at which earth will stand, is taken as the limit of least illumination.
Page 109 - V at r' ; hence tTr' is the required plane, Art. (32). Let the problem be constructed when one of the given lines is parallel to the ground line. Let the problem, to pass a plane through a given point parallel to a given plane, also be constructed. 48. PROBLEM 12. To pass a plane through a given right line, parallel to another right line.
Page 89 - The title. This may be placed outside the border, if it takes up only one line ; but if it requires several, then it must be placed within it. The letters composing the name of the locality...
Page 103 - APPENDIX A. PROBLEMS CONNECTED WITH THE REDUCTION, ENLARGING, AND COPYING OF MAPS OR PLANS. PROBLEM 1. To Construct a Square that shall be a Multiple of any given. Square. Let ABCD ( Fig. 54) be the given square, and let it be required to construct a square that shall contain 2, 3, 4, etc., times its surface. Draw the diagonal BD, and make B a equal to BD — then the square described upon B a.
Page 77 - ... all the outlines have been drawn in and the pencil lines erased, the drawing is prepared for the colouring by being washed. The washing is effected by passing a soft sponge well saturated with clean water gently and rapidly over the surface. The purpose of this washing is twofold; first, to remove those portions of the ink which a wet brush would detach from the paper in laying on the colours, and which, by becoming mixed with the tint, would injure its purity ; jmd second, to damp the surface...
Page 103 - Draw BH, and it will be the side of a square equal to one-half of ABC D. Lay off...
Page 87 - II, measured across the middle, or exclusive of the caps, as the unit, the widths of the other letters, or of their characteristic parts, may be expressed approximately by the numbers in the third column of the table. In case of letters having oblique lines, these widths are to be taken at the intersections of the outer oblique lines with the upper or lower limit of each letter. The caps are in all cases excluded.