PREFACE.My object in the preparation of this text-book has been to present the subject of graphs in a connected form, simple enough in the early stages for the mere beginner while including in the ultimate development such of its more important applications as come within the range of elementary mathematics. The present tendency of mathematical teaching is perhaps to overestimate the value of graphical methods and to depreciate unduly those of analysis; but in spite of the evils attendant upon the reaction from the neglect of graphical methods, these possess, when judiciously used, a high educational value and are of essential importance to all engaged in experimental work.From the educational point of view a graph has the great merit of representing in a simple manner the fundamental notion of functional dependence. The beginner's conceptions of a variable are usually very crude, and it is necessary that they should be clear and definite if he is to understand mathematical princiAbout the Publisher Forgotten Books is a publisher of historical writings, such as: Philosophy, Classics, Science, Religion, History, Folklore and Mythology.Forgotten Books' Classic Reprint Series utilizes the latest technology to regenerate facsimiles of historically important writings. Careful attention has been made to accurately preserve the original format of each page whilst digitally enhancing the difficult to read text. Read books online for free at www.forgottenbooks.org --This text refers to an alternate Paperback edition.