. The Civil engineer and architect's journal, scientific and railway gazette. Architecture; Civil engineering; Science. 378 THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. [November, with regard to its flat foot or base, B C, that it keeps the point A always perpendicular to the plane D E of the drawing-board at the point B ; thus the line A B, in every position whatever of the sliding Fig. drawer, ABC, keeps always parallel to itself; and, therefore, if a pencil is placed at B, whatever A traces at one end is drawn exactly at the other by that pencil. If A traces the contour A F, B draws the
. The Civil engineer and architect's journal, scientific and railway gazette. Architecture; Civil engineering; Science. 378 THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. [November, with regard to its flat foot or base, B C, that it keeps the point A always perpendicular to the plane D E of the drawing-board at the point B ; thus the line A B, in every position whatever of the sliding Fig. drawer, ABC, keeps always parallel to itself; and, therefore, if a pencil is placed at B, whatever A traces at one end is drawn exactly at the other by that pencil. If A traces the contour A F, B draws the contour at B L. When it is requisite to draw another contour the drawing-board is screwed back the distance required by the adjusting screws II H, then the point A will trace another contour, A F, which of course is drawn at B L as before. In this way the whole solid, G, may be traced over. It is hardly necessary to notice that if a metal plate be substituted for the drawing paper, and a grater for the pen- cil, we may secure an engraving plate, whence copies may be taken. By this apparatus profiles of the countenance, of architectural mouldings, and models of maps, may be taken without the use of the screw; and if constructed on a large scale, the lines of a boat, &c, may be taken with ease and expedition. If it be desirable to make a drawing having the effect of a picture, the contours should be drawn close and blunt; but if a measurement drawing, they must be wider apart and sharp, so as to produce no confusion when the back parts are traced over. Fig. 2 represents a plan of a piece of land with three hills laid down in contours from a model; each contour is a representation of the surface at certain given perpendicular distances, say one inch of the model; then, by taking the outer contour as the base or datum, each contour within will represent so many inches perpendicular above the base ; it will thus be seen that the height of the three hills in the model by the anne
Size: 1465px × 1706px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1800, booksubjectarchitecture, booksubjectscience
