66 



SCIENCE. 



[N. S. Vol. XV. No. 367. 



For uniform flow in open channels, the for- 

 mtilte of St. Venant, Bazin, Manning, Tutton, 

 Humphreys and Ahbot, and Gauckler; and 

 extensive tables of the coefiicients to be em- 

 ployed with the formulae of Bazin, Ganguillet 

 and Kutter and Manning. 



A practically new and well-illustrated chap- 

 ter (Chapter IV., of 25 pages and 22 figures), 

 on hydraulic rams, presses, accumulators and 

 water-pressure engines. 



Some of the results of Freeman's experi- 

 ments with nozzles, jets and hose for fire- 

 engines. 



Considerable extra matter in the theoretical 

 treatment of vertical water-wheels and tur- 

 bines. 



A new chapter (of 30 pages and 22 figures) 

 devoted exclusively to centrifugal pumps; 

 giving much practical detail as well as theo- 

 retical treatment. 



References (on pp. 168 and 206) to the 

 recent experiments made at Detroit by Prof. 

 G. S. Williams and others on the flow of 

 water in pipes ; as regards the loss of head due 

 to curves in pipes from 12 to 30 inches in 

 diameter, and the distribution of velocity in 

 the cross-section. (See Proc. Am. Soc. Civ. 

 Engineers for May, 1901, and later discus- 

 sion.) 



It is seen that much of the above added 

 matter has to do with the practical and experi- 

 mental side of the subject; and in this con- 

 nection it is perhaps to be regretted, from -a 

 practical standpoint, that the author had not 

 omitted a large part of the theoretical treat- 

 ment of unimportant and nearly obsolete forms 

 of vertical water-wheels, substituting therefor 

 some account of recent modern turbines and 

 their appurtenances such as the wheels at 

 Niagara Falls and the prominent American 

 makes known as ' Victor,' ' New American,' 

 ' Hercules,' ' McCormick,' etc. ; with a chapter 

 giving methods and results of tests of effi- 

 ciency. 



Criticism and comment on a few incidental 

 points may perhaps be permitted. ' American ' 

 readers of the book may need to be reminded 

 that the gallon employed in the numerical 

 examples (gallon of water) is the Imperial 

 gallon of 2Y1 cubic inches used in England 



and weighing 10 pounds. The weight of the 

 United States gallon (8.32 lbs.) is not men- 

 tioned in the work, although its volume (231 

 cubic inches) is given in the preliminary table 

 of ' Useful Constants.' 



As to the compressibility of water (see p. 5) 

 and corresponding modulus of elasticity of vol- 

 ume, the author might have mentioned the ex- 

 periments described by Mr. Stillman on p. 236 

 of Engineering News of October 4, 1900. In 

 these water was subjected to a pressure of 

 65,000 pounds per square inch, with a resulting 

 reduction of volume of 10 per cent. 



In the treatment of problems involving the 

 steady flow of water in branching pipes the 

 reader might have been reminded of the great 

 saving in time and trouble that can be accom- 

 plished by the use of diagrams of friction- 

 heads in pipes, such as are given in Collignon's 

 ' Hydraulique ' and in Coffin's ' Graphical 

 Solution of Hydraulic Problems,' and inciden- 

 tally in engineering periodicals. (On p. 415 

 of the Engineering Record for November 3, 

 1900, Mr. J. H. Gregory presents such a dia- 

 gram; which, having a logarithmic basis, 

 covers a wide range of values both of diameter 

 of pipe and friction-heads.) Although many 

 results of experiments with pipes are stated in 

 graphic form (Tutton) in the work before us, 

 the diagrams are not arranged with a view to 

 giving aid in the solution of problems. Since 

 only the logarithms, and not the quantities 

 themselves, are figured along the edges of these 

 diagrams, the latter are not available for ready 

 use. 



There would seem to be some inconsistency 

 in presenting the numerical example of p. 161 

 as apparently an illustration of the theory 

 given in article 12 (' Pressure Due to Shock ') 

 of p. 160. In article 12 the closing of the stop- 

 gate is instantaneous, and the kinetic energy 

 of the moving water is absorbed by the elastic 

 compression of the water itself (the pipe being 

 supposed fixed and its possible distension neg- 

 lected). In the numerical example, however, 

 the stop-gate is gradually closed and is sup- 

 posed to be handled in such a way as to make 

 the retardation of the cylinder of water uni- 

 form; and as the kinetic energy of the great 

 mass of the water is gradually given up a 



