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CHAPTER VII.

Quantities of Materials (Cont'd).

II. Volumes from Original Contours.

4. Displacement Diagrams.

Method of Measurement.

The successive displacement areas being numbered in the manner already described, the volume of displacement to any given depth in Cu. Yds. of water displaced is evidently found by Eq. 20, or
V = (L × D² × 2) ÷ (3 × 27) (Sum Even A's + 2 Sum Odd A's – ½ Sum Extreme A's) ... (23)
where L is the unit vertical distance between the displacement surfaces and D is the lineal scale of the plotted diagram.

The volume of water displaced being thus found the corresponding volume of loaded material, is found by introducing the proper coefficient for the given material.

This coefficient is the reciprocal of the specific gravity of the material, and is found by trial for any given material by loading the ganged scow with a measured volume of the given material.

As the conditions are the same, Table 9 will give the Settings and other factors for all problems or operations of this class when the units of measurement are the same. As the vertical distances between the displacement surfaces are usually taken as less than 1 ft., which is the distance adopted for the calculation of the Table, the final volume of displacement must be multiplied in any given case by the rates or per cent which the particular interval in any given case bears to one foot, the Tabular interval.

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