33(> 



NATURE 



[January 21, 1Q09 



could be made with advantage. For example, pp. 119 

 to 136 contain some excellent matter on pyrometers. 

 It is advanced work. From pp. 276 to 358 we are 

 made to wade through much that is quite elementarj' 

 <in conduction, convection, and radiation ! 



There can be no question about the merits of two 

 important sections of the book, viz. the chapter on 

 calorimetry and that on pyrometry. Here the author 

 is clearly doing work which pleases him, work with 

 which he is both theoretically and practically well 

 acquainted, and work which is done in a manner 

 worthy of all praise. We can recommend our 

 engineering students and our practical engineers to 

 obtain the book for the contents of these two chapters. 

 Great care has been expended throughout in the 

 preparation of the text, and although a few of the 

 illustrations might have been improved upon, yet they 

 are, taken on the whole, good. 



As we have suggested above, the title is misleading. 

 Ihe engineer will expect to be able to do without any* 

 other text-book on the theory of heat engines. He 

 will, however, require some other manual, and 

 he will find, in consequence, much overlapping. 

 It must be made quite clear that the contents of 

 " Heat for Engineers " is well written. The author 

 has evidently devoted much labour and thought to 

 the preparation of the book. Considered individually, 

 each chapter is excellent. The above suggestion! 

 have been made in no carping spirit, but in the 

 earnest hope that engineers will obtain fuller benefits 

 in the shape of a more practical text-book from one 

 who clearly is capable of helping them to understand 

 difficult problems. C. A. Smith. 



HlGmVA'ii ENGINEERING. 

 Highway Engineering. By Chas. E. Morrison. Pp. 



'■ + 315- (N'ew York : J. Wiley and Sons; London . 



Chapman and Hall, Ltd., 1908.) Price los. 6d. 



net. 

 A Text-book on Roads and Pavements. Bv F. P. 



Spalding. Third edition, revised and enlarged. 



Pp- X-I-340. (Same publisher.) Price Ss. 6d. net 

 'T'HE first-named of these treatises on highways 

 A was prepared by the author, who is professor 

 of civil engineering at Columbia Universitv, for the 

 students there, '; with a view to furnish a text in 

 which the fundamentals of the subject should not be 

 buried in a mass of detail," and the endeavour has 

 been " to outline and emphasise the basic principles 

 which are essential to good highways." 



The book is divided into ten chapters, dealing re- 

 spectively with road resistance; roads made of earth, 

 gravel, broken stone and other materials; the design 

 of streets, and paving with stone, bricks, asphalt, and 

 wood. It contains a great deal of useful information, 

 especially to engineers having to deal with roads in 

 new countries. The elementary principles of road- 

 making are clearly set out, and copies of specifications 

 suitable for different classes of roads are given. The 

 illustrations are numerous and clear, and in some 

 cases graphic, as, for example, the relative load that 

 can be drawn with the same tractive force on different 

 .\0. 2047, VOL. 79] 



kinds of road is shown by the number of horses 

 required to draw the same load, this number varying 

 fiom half a horse on a first-class road to ten on an 

 earthen track. 



With regard to the repairs of macadamised roads 

 in rural districts, the author emphasises the fact, 

 recognised by all experienced road engineers, that 



"the best results are obtained at a less cost by a 

 system of continuous small repairs, and that to keep 

 a road in an efficient manner, incessant vigilance is 

 required, any signs of ruts or hollows being at once 

 filled up." 



As to trees by the side of roads, the author points 

 out that, whatever may be the disadvantages of road- 

 side trees, it has been the practice in the most pro- 

 gressive road-building countries to plant trees by the 

 roadsides. In France all roads having a width of 

 33 feet or over have a single row on each side, 

 generally at distances varying from 16 to 32 feet 

 apart. In some countries in the rural districts fruit 

 trees are planted for which the road authority derives 

 a revenue by the sale of the privilege to gather the 

 fruit. 



It may also be here mentioned that at the recent 

 road conference at Paris it was agreed that, 

 with a view to dust prevention, the planting 

 of trees along the sides of the roads should bo 

 encouraged. 



The effect of motor traffic on the surface of roads, 

 and the great dust question, which at the present 

 time are receiving so much attention both bv the users 

 and the road authorities, occupy only a small space 

 in this book. The oiled roads that are in use in some 

 districts in the L'nited States are, however, more fully 

 dealt with. With the object of preserving the surface 

 of the road and preventing dust in dry weather, oiled 

 roads are in operation over several hundreds of miles 

 in California and other States. The cross-section of 

 roads subjected to this process is graded to an inclina- 

 tion of half an inch to a foot. Before being treated 

 with the oil the surface is sprinkled with water, then 

 rolled with a light roller, after which a harrow having 

 three-inch teeth is drawn over the surface. The oil is 

 then spread from a specially designed tank cart at a 

 rate varying from 8500 to 18,800 gallons to a mile 

 of road 16 feet in width, or, say, from one to two 

 gallons per square yard. Oils having an asphalt 

 base are best suited for the purpose, but all petroleums 

 are used. The surface of a road treated in this way 

 is fit for the traffic twenty-four hours after being 

 dressed, and is found to be impervious to rain-water, 

 the surface remaining hard and firm also in hot 

 weather. 



The use of bricks for road paving, so frequently 

 met with in Holland, has been introduced into 

 America, especially in the smaller towns, the popu- 

 larity of this form of paving being indicated by the 

 fact that in a period of ten years, out of all the hard 

 paving material used, 33 per cent, was of brick, 

 43 per cent, of asphalt, 10 per cent, of granite, and 

 9 per cent, of wood. The advantages claimed for 

 bricks as a paving material are : a good foothold for 

 the horses, efficient traction, durability under moderate 



