[Book Reviews]

Abstract

THE contents of this book have already appeared in a series of articles in the Building News, but there is no doubt that in book form they will be found more serviceable to readers in general. The articles in question deal in a practical way with the methods of procedure adopted in surveying, and with the descriptions of the different instruments employed. The first chapter treats of surveys with chains only; here the author gives some very sound advice, and concludes it with a description of a worked-out survey, showing also the method of entering measurements in the field-book. In case of obstructions such as rivers, sheets of water, bog land, &c, modifications in the chain line methods have to be adopted, and these are discussed in chapter ii.; the reader is also brought in contact with right-angle instruments, such as the now comparatively little used cross-staff, the optical square, and Weldon's right-angle prism. Next is described the uses of that very important instrument the level, and the different methods of “levelling” are each dealt with. The numerous worked-out “level-lings” with figures, should bring the subject home to the reader. The numerous forms of levels require the author to devote chapter iv. to a discussion of their qualities and of their different means of adjustment. This latter point is of the greatest importance to the surveyor, for on this depends to a great extent the accuracy and rapidity with which observations may be made. The chief levels discussed are the so-called “dumpy” and “Y” types, but other hand-levels are referred to, such as Stanley's builder's level, Watson's clinometer level, and Stanley's Abney and Stanley's improved Abney level. Short reference is made to the barometer as a measurer of differences of level.

Surveying and Surveying Instruments. (The Specialists Series).

By G. A. T. Middleton. (London: Whittaker and Co., 1894).