Originally published in 1906. PREFACE: The author has availed himself of the opportunity, in this revision, to give a complete solution of the elastic arch of variable section. The arch of steel and concrete combined is taken up in detail to illustrate the general graphical treatment. The method to follow for other arches, as those of steel, stone or concrete, is at once apparent from the general solution. The aim throughout has been to give a clear analysis of principles involved, a knowledge of the fundamental principles of the equilibrium polygon being alone assumed.....Many of the earliest books, particularly those dating back to the 1900's and before, are now extremely scarce and increasingly expensive. We are republishing these classic works in affordable, high quality, modern editions, using the original text and artwork.