A textbook on mechanical and electrical engineering (1902)
International Correspondence Schools · Scranton : International Textbook Co. · leaf 288
be drawn, soanother base line will be required. This base line, beingmerely the lower boundary of a surface supposed to be in anupright position to receive the lines of sight and at rightangles to the surface of the elevation previously drawn, will,consequently, be at right angles with the base… … Fig. 10 of the lines of sight from still another direction than hasbeen shown in the preceding illustrations. In the samemanner a view may be obtained from any side of an objector at any angle other than a right angle. The method ofaccomplishing these results by the use of the T square andtriangle…
