This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1857 Excerpt: ...h', k', at right angles to the intersecting line (art. 28); and their lengths will be determined by drawing lines from the lower ends of lines l, 2, 3, No. 2, in the same manner as described for the projection of No. 3, Art. 83. Art. 94.--There is one point to which we must direct the careful attention of the student. ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1857 Excerpt: ...h', k', at right angles to the intersecting line (art. 28); and their lengths will be determined by drawing lines from the lower ends of lines l, 2, 3, No. 2, in the same manner as described for the projection of No. 3, Art. 83. Art. 94.--There is one point to which we must direct the careful attention of the student. Line l 4, No. 2, represents the upper face of the cube; that is to say, it represents a plane which is at right angles to the vertical plane of projection. The line of section e f also represents a plane at right angles to the vertical plane. Now, when two planes which are at right angles to the vertical plane intersect each other, the line of intersection will be represented by a point, as l, No. 2; and the projection of that point in the upper or vertical plane will be a line drawn parallel to such plane and also to the intersecting line; and the projection of that line in the lower plane will be a line parallel to that plane and also to the intersecting line. Art. 95.--We have now to find a plan of No. 5, or the appearance that figure would have if viewed in the direction of the arrow c, which is supposed to be parallel to the vertical plane. From Theorem 2, it follows that the plan of point 4 must be somewhere in the projecting ray from that point. Let 4, No. 6, be the position of that point in the lower plane. Now the plan of points l," l', will also be in lines drawn from those points at right angles to the intersecting line; the question, therefore, is (and these remarks apply to all the points in this figure), how are we to determine their position with regard to point 4? Remember that No. 5 is a view of No. 2, looking at that figure in the direction of the arrow b. It is evident, therefore, that point l is nearer to the eye than ...
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