The number of beads on each wire can represent to scale the data for the particular square at the center of which the bead wire is placed. The heights of the columns of beads on the different wires would then show clearly the facts for any one section of the field in a manner similar to that of Fig. 167. The beads would probably be more generally understood by an untrained person than the isometric drawing of Fig. 167, and it is for this reason that the scheme is mentioned here. The arrangement by columns seen in Fig. 167 is satisfactory for the trained reader, but the separate beads on wires would probably give a less abstract impression, more easily grasped by the average person.

Chapter XI MAP PRESENTATIONS

MAPS marked, colored, or shaded in different ways, or used in conjunction with pins or other signals, form one of the most convenient means of conveying information. Such maps may be used to advantage in a surprising variety of ways, only a few of which can be mentioned here.

Engineers who have with great labor prepared complete plans, specifications, and estimates for some proposed improvement are frequently disappointed that they cannot arouse enough enthusiasm in the proposed scheme to obtain the approval of the government or municipal officials, or members of a corporation board of directors, who must vote in favor of the plan and appropriate the money necessary to carry it into effect. It is always difficult to get non-technical persons to take an interest in proposals which are shown only by blue prints and ordinary maps. Architects realize this so well that it is common practice among them to submit carefully prepared wash-drawings to show the appearance of the building for which they are submitting plans. Most engineering work cannot be easily represented by washdrawings, and the engineer is accordingly somewhat handicapped as compared with the architect in arousing interest in his project.