March of each year, and is subject to correction till the first of July, while later information is admitted in the form of advertisements up to the hour of going to press. The publishers believe that the present—the seventh—is an improvement upon any preceding volume; and the information has been more carefully gathered, and is even more trustworthy, than heretofore. There have recently been added to the headings descriptive of States and counties sections showing, from the census of 1880, the number of manufacturing establishments of all kinds at that time, with the amount of capital invested in them, the number of hands employed, and the value of their annual products, while the State headings show, in addition to the summaries of these facts, the amounts paid in wages, and the value of the raw materials used.
The Theory and Practice of Surveying. By J. B. Johnson, C. E. New York: John Wiley & Sons. Pp. 683, with Maps and 150 Text Illustrations. Price, $3.50.
The large field which the word surveying necessarily covers, renders every attempt at bringing all the different materials together in one volume a rather difficult and perplexing task. Theory and practice are, in hardly any other branch of human activity, so closely connected with each other as they are in the execution of surveyor's work, in which the most exact methods and appliances have to be used in order to secure the degree of accuracy which is always desirable, whether the surveying be done for scientific and national purposes or for the protection of private interests.
The volume under review is designed for the use of surveyors and engineers generally, for whom it will be a valuable reference-book; but it is intended especially for the use of students in engineering, who will find it a complete guide in their studies, containing all that should be familiar to them when they enter practical life as engineers or surveyors.
The text is divided into fifteen chapters, with some appendices and tables. All the apparatus described are, when necessary, shown in illustrations. The instruments used by surveyors are described in the first part, the first six chapters being devoted to instruments for measuring distances, instruments for determining directions, instruments for determining horizontal lines, instruments for measuring angles, the planetable, and additional instruments used in surveying and plotting.
The second part is devoted to the methods which find application in surveying, the separate chapters being devoted to land surveying, topographical surveying by transit and stadia, railroad surveying, hydrographic surveying, mining surveying, city surveying, the measurement of volumes, geodetic surveying, projection of maps, map-lettering, and topographical symbols. The chapters devoted to railroad, hydrographic, mining, and city surveying—the two latter of which the author acknowledges have been contributed respectively by C. A. Russell, C. E., U. S. Deputy Mineral Surveyor of Boulder, Colorado, and William Bouton, C. E., City Surveyor of St. Louis, Missouri—are of special interest even to practiced surveyors, as they treat of special branches of surveying, about which little, if any, mention is ever made in books for the use of students.
What may be called the scientific part of surveying—geodetic surveying—is fully treated and made comprehensible to those whose purpose is not to devote themselves to geodetical work exclusively, but who have, all the same, to be familiar with the scopes and purposes of geodetical measurements, as every engineer and surveyor has to be.
Of the appendices, one is on the judicial functions of surveyors, by Justice Cooley, of the Michigan Supreme Court; the second is a copy of instructions to United States Deputy Mineral Surveyors for the District of Colorado (1886), while two others contain derivations and formulas. A number of tables for easy reference and for practical use are added at the end.
Three plates accompany the text. One is an isogenic chart of the United States, containing all the data accessible up to 1885, reduced from the United States Coast Survey Chart; Plate II contains all the conventional signs for topographical maps; and Plate III is a topographical practice survey executed by the sophomore class in the Polytechnic School of Washington University. The author is Professor of Civil En-
