Practical engineering drawing and third angle projection, for students in scientific, technical and manual training schools and for ..draughtsmen .. . d theplane of projection. 384. The same grouj)ing can Ije arrived at liy a different conception, which will, to some, haveadvantages over the other. It is illustrated l\v Fig. 228 (b), in which the same oliject as before is *For the convenience of those who have to take up this subject without previous study of Descriptive Geometry theThird-Angle section of tliis chapter is made complete in itself, hy the re-statement of the principles involved
Practical engineering drawing and third angle projection, for students in scientific, technical and manual training schools and for ..draughtsmen .. . d theplane of projection. 384. The same grouj)ing can Ije arrived at liy a different conception, which will, to some, haveadvantages over the other. It is illustrated l\v Fig. 228 (b), in which the same oliject as before is *For the convenience of those who have to take up this subject without previous study of Descriptive Geometry theThird-Angle section of tliis chapter is made complete in itself, hy the re-statement of the principles involved and which havebeen treated at somewhat greater length in the previous chapter: although a review of such luatter may be by no meansdisadvantageous to those who have already been over the fundamentals. 132 THEORETICAL AND PRACTICAL GRAPHICS. sujoposed to be smTdumled by a system of mutually-peqiendieular transparent ]ilanes, or, in otherwords, to be in a box having glass sides., and on each side a drawing made of what is seen throughthat side, excluding the idea, as before, of jierspective ^new, anil representing each point by a per- X^ig-- 233,. iiPiii||l||[r|[i(B«p™R|^ pendicular from it to the j)lane. The whole sj^stem of box and planes, in the wood-cut, is rotated90° from the position shown in Fig. 228(a), liringing tliem into the usual position, in which theobserver is looking perpendicularly toward the vertical plane. ^igr- 22Q.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjec, booksubjectlettering
