Plate V. is a map of the Harbor and City of New Haven, reduced from the charts of the U. S. Coast Survey, without the depth of soundings or the marks of shoals. Plate VI. is a representation of map drawing as executed by the brush in India ink only. The hills are drawn with a comb-edged brush in nearly dry color, as already described; in the following plate they are in blended tint. Plate VII. a similar map in color, represented according to the conventional signs, and executed as described in the previous pages. Plate VIII. contains plan and sections of strata of a lead mine copied from Greenwell's "Mine Engineering," intended as illustrations in this department of the profession. On geological maps sections are similarly represented, and plans are colored in patches according to the formation. Shades of India ink usually represent coal measures; of blue, limestone; of pink, the igneous rocks, as trap, granite, &c. In all cases, there are small blocks of color at the margin of the map, to designate the mineral represented by each. In all the departments of drawing, we have thus tried to illustrate as fully as the limits of this work would admit, the general principles of representation and the rules of projection; but in addition, we would recommend to every one who wishes to make himself a perfect draughtsman, that he should collect good charts and drawings, study them, and in his leisure moments copy them. In this way he will acquire a readiness of manipulation, and ease and freedom of expression. |