. School: a monthly record of educational thought and progress. the instrument combines two views of the samesolid from slightly different points of view, and, if heis allowed the use of one—the cheap American oneson the market at one shiUing or less serve admirably—will probably want to make stereographs of his this involves drawing in perspective, he may soonbe induced to learn how to deal with the cube, andhence with many interesting solids. We give in Fig. 5a stereograph of the Kelvin, with an indication of thecube from which it is derived. Readers who do notwish to cut this out may
. School: a monthly record of educational thought and progress. the instrument combines two views of the samesolid from slightly different points of view, and, if heis allowed the use of one—the cheap American oneson the market at one shiUing or less serve admirably—will probably want to make stereographs of his this involves drawing in perspective, he may soonbe induced to learn how to deal with the cube, andhence with many interesting solids. We give in Fig. 5a stereograph of the Kelvin, with an indication of thecube from which it is derived. Readers who do notwish to cut this out may easily reproduce it by prickingthrough on to a card. Various little practical devices for shortening thelabour involved in such drawings may be found outor pointed out as the subjects grow in there is little difficulty in proving once and for allsome of the constructions for the position of a point onthe picture plane whose height and distance fromit are known if a few threads and rods are used in con-nection with a vertical frame. Fig. 5. Perspective may be made to lead naturally to theproperties of corresponding points, and to the elementsof Projective Geometry, and thus to introduce thestudent to some of the powerful instruments of researchwhich modern geometers have placed at his disposal. The models discussed hitherto have been supposedconstructed of paper or card, and to have indicated thenature of the soHd by giving the plane surfaces containingit, but those constructed of wires and threads havetheir special uses. Large models for class-work maybe made of stouter and rougher materials. I havefound bamboo very useful. Fig. 6 shows the construction of a model to illustrateEucHd XL, 6 (or 8). The board stands for the planeMN. The stout uprights, AB, CD, at right angles to it * This instrument may also be utilised for bringing out theactual arrangement and position of the lines in the figures to thepropositions of an ordinary school course in Solid Geomet
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License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookidschoo, bookpublisherlondon
