344 SCIENCE PROGRESS 



Almanac. An appendix on Compass Adjusting has been added to this (second) 

 edition. 



H. S.J. 



Textbook on Practical Astronomy. By George L. Hosmer, Associate Pro- 

 fessor of Topographical Engineering, Massachusetts Institute of Technology. 

 Second Edition. [Pp. be + 205, with 78 figures.] (New York : John 

 Wiley & Sons ; London : Chapman & Hall, 1917. Price gs. 6d. net.) 



The first edition of this work appeared in 1910, the purpose of the author being 

 to meet the needs of students of civil engineering, who have not sufficient time 

 to devote to the advanced study of astronomy, but who require more than the 

 short chapter usually given in textbooks on surveying. The book therefore deals 

 mainly with the class of observations which can be made with surveying instru- 

 ments, and the author has wisely omitted reference to those requirements which, 

 though of vital importance in precise astronomy, are beyond the accuracy of an 

 engineer's observations, and would only tend to confuse the student. 



The author has kept the requirements of such students well before him, and 

 the elementary principles are explained in great detail and with numerous 

 diagrams ; in particular, the methods of measuring time, which are frequently so 

 confusing to beginners, are clearly and carefully explained. The use of the 

 Nautical Almanac and star catalogues are dealt with. The corrections to observed 

 altitudes on account of the earth's figure, parallax, refraction, dip, etc., are explained 

 with examples. Descriptions of the principal observing instruments — transit, 

 sextant, chronograph — are given. A short chapter on the Constellations is included, 

 and the remainder of the text contains a selection of the most suitable methods of 

 observing latitudes, time, longitudes, azimuths, and positions at sea. Several 

 useful tables are given at the end of the volume, including tables for computing 

 the azimuth of Polaris at any hour angle (furnished by the U.S. Coast and 

 Geodetic Survey). The volume contains throughout the text numerous examples 

 worked out in detail to illustrate the principles, and other examples are given for 

 the student to solve for himself. The volume is therefore eminently suitable for 

 the student who is pursuing a course of study on his own. A short appendix on 

 the tides has been added. 



H.S.J. 



PHYSICS 



Electrical Phenomena in Parallel Conductors: Vol.1, Elements of Trans- 

 mission. By F. E. Pernot, Ph.D., Assoc. Member A.I.E.E. [Pp. xii + 

 332, with 83 diagrams.] (New York : John Wiley & Sons, Inc., 1918. 

 Price iSs. bd. net.) 



Some thirty years ago, when the problem of the transmission of electric dis- 

 turbances along wires was first solved by Heaviside, the solution was found so 

 difficult that the engineer had to neglect it. Later on, when our own Post Office and 

 the late National Telephone Company were forced to consider the solutions for the 

 case of long-distance telephony, simpler methods were devised of discussing 

 the problem, and tables of hyperbolic functions were specially constructed to 

 obviate the labour of computation. In this book the author discusses the problem 

 mainly from the point of view of the power engineer. He points out that, now 

 elaborate tables of the hyperbolic functions are available, it is unnecessary to use 



