October 11, 1901.] 



SCIENCE. 



573 



area. This rather than the original meaning 

 of the term seems destined to persist. 



The work of Wernicke is likewise intended 

 for elementary students, and was evidently 

 prepared for home use especially, since it is 

 printed in German type. It is far too detailed 

 a work, as may be inferred from the title page, 

 not all of which is quoted above, to meet with 

 favor, except in reference libraries on this side of 

 the Atlantic. The authors leave little room for 

 play of the student's imagination and less room 

 for the development of his originality. Every- 

 thing is explained in extenso, and often in a 

 provokingly complicated or inelegant fashion. 

 The beautifully drawn diagrams convey too 

 much information ; and the many numerical 

 examples seem well calculated to obscure 

 rather than to illustrate salient principles. 

 The work is one of the happily passing texts 

 that try to present mechanics with little or no 

 use of the calculus, and thus waste a deal of the 

 student's time. There is much useful informa- 

 tion in the volumes, however, and they may 

 prove handy for those who cannot bring an 

 adequate preparation to the subject. 



The first volume is devoted to mechanics 

 proper and gives an elementary view of the 

 principles applicable to rigid bodies, with many 

 applications to machinery. The second volume 

 treats of gases and liquids, with applications to 

 pumps, injectors, water motors, ventilators, etc. 

 The second volume is supplied with a good index, 

 but the first volume has none. R. S. W. 



Water Filtration Works. By James H. Fuertes, 



M. Am. Soc. C. E. New York, John Wiley 



& Sons ; London, Chapman & Hall, limited. 



Cloth, 5 X8 in. 19 plates and 45 figures in 



the text. 1901. Price, $2.50. 



In this work the author has discussed in a 



clear and very readable form the theory and 



practice of water filtration as it stands to-day. 



As preliminary to the subject proper the author 



devotes a short chapter to a brief statement of 



the relation of typhoid fever to polluted water 



supplies, and discusses the various processes of 



natural purification and the means of protecting 



surface waters from pollution. The great value 



of filtration as a means of purification is also 



here set forth. Chapter II. deals with intakes 



and sedimentation basins. The former subject 



is treated very briefly and mainly with refer- 

 ence to questions pertaining to quality ; the 

 latter subject is treated quite fully, as is quite 

 proper in a work on filtration, since clarifica- 

 tion by sedimentation is very frequently an im- 

 portant part of the purification process. 



Following these two chapters is a full discus- 

 sion of the subjects of slow sand-filtration and 

 rapid or mechanical filtration, in each case the 

 underlying theory being first set forth and then 

 matters pertaining to the design, construction 

 and operation of works. In Chapter VII. are 

 given the author's conclusions as to the relative 

 advantages of the two systems, together with 

 suggestions as to possible combinations. A 

 few pages are also devoted to a very brief 

 consideration of minor processes of filtration. 

 It was doubtless proper to omit any considera- 

 tion of household filters, but in a special work 

 of this kind it would seem that a fuller treat- 

 ment of the use of filters in the removal of 

 color and of iron in solution might have been 

 desirable. A brief chapter on flltered-water 

 reservoirs completes the volume. 



A noteworthy feature of the work is the full 

 and valuable data relating to the operation of 

 filter plants and settling basins. The design- 

 ing engineer will also find convenient the nu- 

 merous conversion tables and diagrams con- 

 tained therein. The book is well illusti-ated by 

 half tones showing interesting phases of con- 

 struction and operation, and by well-executed 

 cuts of details, particularly of filter-regulating 

 devices. As a whole, the work places before 

 the engineer a good summary of the latest in- 

 formation on this important subject, and at the 

 same time presents the matter in a way to be of 

 interest to the general reader. 



F. E. TUENEAUEE. 



DISCUSSION AND CORRESPONDENCE. 



IS IT NOT TIME THAT THE TITLE ' PEOFESSOR 



OF AGRICULTUEE ' SHOULD GO OUT OF USE ? 



In most of our State institutions, known gen- 

 erally as Agricultural and Mechanical Colleges 

 or Land Grant Colleges, we have what is known 

 as the Agricultural Department, together with 

 other Departments of the College, as, for ex- 

 ample, the Mechanical, Civil and Electrical 

 Engineering Departments, the Chemical, Bio- 



