86 Reviews — Ries & Watson — Engineering Geology. 



principles of geological science, and a careful study of it will enable 

 the engineering student to face with confidence the many problems, 

 so varied in character, that he may encounter in the course of his 

 professional career. The scope of the book is wide, and covers such 

 diverse subjects as the character of rocks in respect of their use for 

 building purposes or for road-making, the structure of rocks so far as 

 it may affect tunnelling operations and building dams or reservoirs, 

 the conditions which determine the flow of underground waters, the 

 character of soils in connexion with the disposal of sewage and 

 the purification of water, the ingredients of cements and clays, the 

 sources of coal and oil, and the nature of ore deposits. The value of 

 the book to the engineering student is enhanced by the fact that the 

 discussion always follows strictly practical lines; instances, mostly 

 drawn from American occurrences, illustrating the point in question 

 being described. The ample illustrations are well chosen and excellent 

 in character, and the bibliography of American literature at the close 

 of each chapter enables the reader to prosecute his study further if he 

 so desires. The volume is, in fact, one that should find a place on 

 the shelves of every civil engineer. 



In the early chapters a brief survey is given of such parts of 

 mineralogy and petrology as are immediately related to the subject. 

 The necessary brevity has entailed some looseness in expression ; it 

 may, for instance, be questioned whether the definition of a mineral 

 as " any natural inorganic substance of definite chemical composition ", 

 or of a crystal as "a solid bounded by flat and somewhat smooth 

 surfaces, called faces, symmetrically grouped about imaginary lines as 

 axes", be logically satisfactory. In the discussion of the physical 

 characters of minerals it is pointed out that the colour may he natural, 

 i.e. bound up with the essential composition, or exotic, i.e. due to the 

 presence of some foreign pigment, and the authors say in the case of 

 iron that " according to the amount present the mineral will ordinarily 

 exhibit some shade of green, brown, or even black", but do not 

 mention the difference of tint depending upon the state of oxidation 

 of the iron. The characters of the principal rock-forming minerals 

 are described in the order — silicates (the largest group), oxides, 

 carbonates, sulphates, phosphates, and sulphides. The discussion 

 being based upon the microscopic appearance, little is said about the 

 optical properties. The second and third chapters deal with the 

 general characters of rocks, divided into the customary groups — 

 igneous, sedimentary, and met^morphic — and their structure and 

 metamorphism The authors then pass on to the weathering of rocks 

 and the soils resulting therefrom, the surface and underground waters, 

 landslides, wave action, lakes, and glacial deposits. In a subsequent 

 chapter the different kinds of building stones in use are fully treated, 

 and their capacity to withstand the disintegrating effects of weathering, 

 mechanical stress, and extreme heat is discussed in considerable 

 detail. It. is pointed out that the quarrymen, and we might add the 

 general public, use the term granite in a far wider sense than is now 

 usual in science. The properties of limes and cements, and the rocks 

 used in road making are described, and the concluding chapter is taken 

 up with the important subject of ore deposits. Maps showing the 



