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 in Fig. 205, in which direction the executive desires that the curve should trend. In Fig. 205, which represents total sales, the head of the arrow of course points upward. If the curve is to show expenses per unit of output, the head must be placed on the vertical line so that the arrow will point downward. In Fig. 206 no head is placed on the arrow, as fluctuations in a payroll mean nothing unless we know the output of work. An increasing payroll may result either from increasing sales or from inefficient production. A decrease in payroll may result from increased efficiency of production or because sales have fallen off undesirably. Accordingly, no head is placed on the arrow and the curve must be interpreted by conditions other than those shown on the face of the card itself. In general, all curves relating to total money expenditures may trend either up or down, without meaning anything unless other conditions are considered. It is only when we express expenditures as expenditure per unit that we really get a curve for which it is safe to say that we should always desire a downward trend as long as quality is maintained.

Forms for executive records such as are shown in Fig. 205 and Fig. 206 should be printed on an especially high grade of paper. Most paper in use to-day contains sulphite pulp and chemicals which cause more or less rapid deterioration. The paper commonly used turns brown and gets brittle within five or ten years, so that records on this paper are likely to become useless in a comparatively short time. High-grade paper to be used for the record cards shown in Fig. 205 and Fig. 206 should contain only the finest selected linen stock and should be guaranteed absolutely against any deterioration for twenty years. The chief advantage of such paper, however, is that it can be used in card form, yet be transparent enough to allow of blue-printing.

The time required to blue-print cards made from such paper may best be compared with the time necessary when ordinary tracing cloth is used. Blue prints are also frequently made from bond paper. Bond paper requires an exposure of, roughly, three times as long as tracing cloth. A special card made of heavy paper would require an exposure of about six times as long as tracing cloth, or twice as long as bond paper.

When sunlight is used for blue-printing, there is no difficulty in getting a sufficiently long exposure to make good blue prints from the card forms shown in Fig. 205 and Fig. 206, if the forms are printed on selected paper. Should electric blue-print machines be used, however, it may be found that certain of the older types of continuous printing