Septeubeb 24, 1909] 



SCIENCE 



411 



the fullest recognition of the extremely com- 

 plex magmatic solutions from which they have 

 come and of the varied conditions determining 

 the characters of the rocks themselves, and not 

 infrequently producing rocks of different min- 

 eral composition from a single magma. 



This volume is a treatise on igneous rocks 

 which is manifestly an unfettered expression 

 of the author's understanding of them rather 

 than a text-book. Yet it outlines so logically 

 the view of these objects which the student 

 should be made to understand that it may be 

 used as the basis of instruction in all advanced 

 courses. 



The book appears in uniform style with 

 " Rock Minerals " by the same author. The 

 second volume, descriptive of known rocks, is 

 in preparation, and will be awaited with in- 

 terest and with the hope that the author may 

 be successful in making his subject more at- 

 tractive than is the case with existing litera- 

 ture of the kind. Whitman Cross 



Railroad Structures and Estimates. By J. W. 

 Orruck, C.E. New York, John Wiley & 

 Sons. 270 pages, 94 illustrations. $3 net. 

 Probably the primary purpose of this book 

 is to furnish data for estimating the various 

 parts of a railroad, and it contains a compila- 

 tion of cost data which should prove of value 

 to many a young engineer, not only in fur- 

 nishing reasonable figures of costs, but also in 

 stimulating him to secure similar figures for 

 his own locality or from his own railroad. 

 Costs vary from time to time and also locally, 

 so that figures for estimates can not safely be 

 swallowed whole either from this book or any 

 other. A book of this sort then should find 

 its best value in suggesting methods of cost 

 estimation, and in analyzing the constituent 

 parts of costs. This book is somewhat uneven 

 from this standpoint, some chapters having 

 the elements of cost well classified, while 

 others are very general, as in the costs of 

 tunnels where a short table of costs per lineal 

 foot is quoted from Drinker's rather ancient 

 treatise; while the estimates for turnouts are 

 itemized, the cost of a split switch is given as 

 $30 to $50; and similarly for laying and sur- 



facing it, $30 to $.50 ; a' variation of consider- 

 able amount without special explanation to 

 account for it. The criticism applies perhaps 

 to the difficulty of the subject rather than to 

 inferiority of treatment. 



The compilation of cost data involves a 

 knowledge of the structures or materials to be 

 built or used; as a result a large share of the 

 book is given to such descriptions, or some- 

 times practically specifications. There are 

 given, also, a number of tables which seem 

 hardly consistent with the general purpose of 

 the book ; among these are one " for putting 

 in frogs and switches," others for " feet head 

 and equivalent pressure in pounds per square 

 inch," " friction of water in pipes," " friction 

 of water in elbows " ; also a table of " horse- 

 power." 



The chapter on buildings, covering eighty- 

 eight pages, is quite largely given to descrip- 

 tions, and these cover many classes of build- 

 ings; it has not quite the merit of a treatise 

 and yet any one is likely to find there some 

 thing he wants and which is worth while. In 

 the estimates of this chapter, some are well 

 analyzed and itemized, while some others are 

 very general and with wide range of cost 

 values, a freight shed with modem floors being 

 estimated at 25 to 50 cents per square foot. 



The chapter on Specifications and Contracts, 

 covering thirty-one pages, is inadequate, and 

 except for four pages on estimates, hardly in 

 line with the apparent purpose of the book. 



The book in its mechanical make-up has the 

 general appearance and quality of the Wiley 

 books on engineering, which means that it is 

 satisfactory. The scope is indicated by the 

 following Chapter Index: 



I. Track Materials. II. Fences, gates, sign 

 posts, m. Culverts. IV. Bridges. V. Build- 

 ings. VI. Water Stations. VII. Tanks. 

 VIII. Specifications and Contracts. IX. Esti- 

 mating Notes. 



C. F. Allen 



Neuere Ergehnisse auf dem Gehiete der Spezi- 

 ellen Eiweisschemie. Prof. Emil Abder- 

 HALDEN. Jena, Verlag v. Gustav Fischer. 

 " Die Neueren Ergehnisse auf dem Gehiete 



