466 



NATURE 



[September 17, 1903 



Though, however, the present book, like its prede- 

 cessor, is intended primarily for students in colleges 

 and technical schools, and secondly for engineers, and 

 one or more problems, intended to be solved by the 

 reader, are appended at the end of each article, relating 

 to the special subject treated of in the article, it deals 

 ■with the various hydraulic principles and problems 

 successively investigated in a more simple manner 

 than the former book, which is calculated to commend 

 it to the favourable notice of practical engineers, too 

 engrossed in their work to be able to spare the time 

 for fully grasping abstruse mathematical considera- 

 tions. 



The book is divided into sixteen chapters, and is 

 further subdivided into one hundred and ninety-two 

 articles, each numbered, and dealing with a subject 

 under a special heading connected with the general 

 purpose of the chapter which contains it ; whilst an 

 appendix at the end, occupying forty-three pages, after 

 pointing out certain analogies between the flow of 

 water in pipes and the passage of the electric current 

 along wires, and adding some miscellaneous problems 

 for solution, furnishes fifty-five useful hydraulic and 

 mathematical tables, the former being given both in 

 English and in metric measures. 



The first four chapters treat successively of " Funda- 

 mental Data," " Hydrostatics," " Theoretical Hydrau- 

 lics," and "Instruments and Observations"; whilst 

 the following six chapters are devoted to the considera- 

 tion of the various kinds of flow, namely, through 

 •orifices, over weirs, through tubes, through pipes, in 

 conduits, and the flow of rivers. The remaining six 

 chapters deal with the important practical subjects of 

 "Water-Supply and Water-Power, " "Dynamic 

 Pressure of Water," " Water- Wheels," "Turbines," 

 "Naval Hydromechanics," and "Pumps and Pump- 

 ing." Nearly two hundred figures in the text, mostly 

 in the form of small, simple diagrams, serve still 

 further to elucidate the hydraulic principles so clearly 

 and concisely enunciated ; and these diagrams, instead 

 -of being numbered consecutively in the usual manner, 

 are given the same number as the articles which 

 they illustrate, adding a, ft, c, &c., where more than 

 one occur in a single article; whilst the same system 

 of numbering is adopted for distinguishing the 

 formulas given in the several articles, and the prob- 

 lems appended at the end of them. The advantage of 

 this peculiar method of numbering is not very clear, 

 though possibly it furnishes an excuse for omitting 

 headings from the diagrams, and for dispensing with 

 a list of them. By the above arrangement, however, 

 each article, with its special number and descriptive 

 heading, constitutes a distinct unit, in which the 

 diagrams and formulas are merged; and whereas the 

 chapters in the text are only headed by their special 

 -subject, the headings in the table of contents under the 

 main headings consist merely of an enumeration of 

 the headings of the articles in each chapter, preceded 

 by their distinguishing numbers. 



The way in which several independent articles are 

 grouped together in the chapters to which their sub- 

 jects appertain, is well illustrated by the list of articles 

 -contained in the chapter on naval hydromechanics, 

 NO. 1768, VOL. 68] 



comprising "General Principles," " Frictional Re- 

 sistance," "Work for Propulsion," "The Jet Pro- 

 peller," "Paddle-wheels," "The Screw Propeller," 

 " Stability of a Ship," " Action of the Rudder," and 

 "Tides and Waves." The concise and somewhat 

 Qursory manner in which the practical subjects con- 

 sidered in the last six chapters are touched upon, is 

 sufficiently indicated by their taking up less than one- 

 third of the whole contents of the book, and by such 

 important and complex questions as water-supply and 

 water-power being together dealt with in a single 

 chapter of twenty-eight pages. This circumstance, 

 however, must not be regarded as at all detracting 

 from the merits of the book ; for evidently the author 

 is mainly concerned in laying down the principles of 

 hydraulics, indicating the means and methods of tak- 

 ing observations, and establishing the laws of the flow 

 of water under various conditions, to which subjects 

 considerably the larger portion of the book is devoted. 

 Then, after the principles and laws of hydraulics have 

 been thoroughly elucidated, the methods of their appli- 

 cation to various practical purposes, such, for instance, 

 as water-power, water motors, propulsion, and pump- 

 ing, are successively indicated, without the slightest 

 intention on the part of the author that the brief treat- 

 ment of these subjects should furnish substitutes for 

 the standard treatises on them. 



In the latter part of the book, indeed, the general 

 features of the subjects introduced, and the action of 

 the hydraulic machines are concisely sketched in sug- 

 gestive descriptions, leaving a full investigation of the 

 various matters touched upon to be sought elsewhere, 

 according to the special branch on which more detailed 

 information is required. Nevertheless, in spite of the 

 brevity of the treatment, interesting particulars are here 

 and there referred to, as, for example, the present utilis- 

 ation of the Falls of Niagara in the development of 

 105,000 electrical horse-power, by means of turbines 

 which are described, and the prospect in the near future 

 of a largely increased use of this natural source of 

 power ; whilst it is suggested that the tides and waves 

 afford a source of power which at present is wasted, 

 but which, on the exhaustion of the supplies of coal, 

 wood, and oil, may be utilised for generating power, 

 heat, and light in unlimited quantities. 



OVR BOOK SHELF. 

 Synthesen in der Purin- und Zuckergruppe. By Emil 



Fischer. Pp. 29. (Braunschweig : Friedrich Vieweg 



und Sohn, 1903.) 

 This lecture, delivered before the Swedish Academy at 

 Stockholm on December 12 of last year, contains an 

 account of Prof. Emil Fischer's work in organic 

 synthesis, and of the motives that have guided him 

 in attacking successively the problems of the uric acid, 

 sugar, and more recently the albuminoid, groups of 

 organic compounds. The synthetical methods by 

 which the constitution of so many naturally occurring 

 substances have been determined are described in out- 

 line only, and in a way that will appeal especially to 

 the non-chemical reader. To the chemist the chief 

 charm of the lecture lies in the frankness with which 

 the lecturer describes the purpose and the ultimate 

 goal of the work to which he has devoted himself. 



