The Theory of Engineering Drawing (Classic Reprint)

Goso FEB 191 SC AD5 PREFACE Although the subject matter of this volume is, in large measure, identical with that of many treatises on descriptive geometry, the author has called it Theory of Engineering Drawing, believing that this title indicates better than could any other, the ultimate purpose of the book. That texts on descriptive geometry appear with some degree of frequency, with but few, if any, additions to the theory, indicates that teachers are aware of certain weaknesses in existing methods of presenting the subject. It is precisely these weakness that the present work aims to correct. The author emphasizes the fact that the student is concerned with the representation on a plane of objects in space of three dimensions. The analysis, important as it is, has for its primary purpose the development of methods for such representation and the interpretation of the resulting drawings. It is nowhere regarded as an end in itself. The number of fundamental principles has been reduced to a minimum; indeed it will be found that the entire text is based on the problem of finding the piercing point of a given line on a given surface, and a few additional operations. The accepted method of presenting the subject, is to start with a set of definitions,to consider in detail the orthographic projection of a point, and then, on the foundation thus laid, to build the theory of the projection of lines, surfaces, and solids. Logical and beautiful as this systematic developmeen may be, it nevertheless presents certain inherent difficulties, chief of which is that the student is confronted at the outset with that most abstract of all abstractions, the mathematical point. In this volume the order of presentation is reversed and the reader is asked to consider first some concrete object, a box, for instance, the study of which furnishes material of use in the later discu
(Typographical errors above are due to OCR software and don't occur in the book.)