不規則多辺形断面の新求積法及求積定規の新考案に就いて

抄録

In the designing practice of the earth works of the road and railway construction, the areas of the successive cross-sections, which are usually assumed to be irregular polygons and figured on a sheet of section-papers, should be carefully measured to obtain an accurate estimation of the earth volume to be cut or filled. Three methods, e. i. 1) Direct reading from the sectionpaper, 2) Use of a planimetre, 3) Deviding the figure into triangles, are the usual procedure of measuring, each one of which is more or less laborious and inaccurate to attain good results. A new method of measurement was established by the author, in which, the principle of graphical integration was applied and the amount of a cross-sectional area was reduced to a certain length of a straight line, the measurement of this linear length was the only procedure required ; and thus the operation of the areal measurement was considerably simplified. To realize easier eperation of the graphical drawing and the measurement, a handy scale, rectangular frame hinged at each corner and composed of celloid plates and an attatcheb pin, was also devised by the author. This new scaling instrument was proved to be used for the practical operation with sufficient efficiency and convenience.