June 20, 1901] 



NA TURE 



179 



who are most au couiant with this subject. There 

 are many indefinite statements such as the following ; 

 " it may happen that a particular geological stratum 

 contains a considerable excess of chlorine," "some 

 geological strata contain nitrates to some considerable 

 degree," "speaking as a rule to which there are of 

 course notable exceptions, drinking water ought not to 

 contain more than 05 part per 100,000 of nitric 

 nitrogen." 



It is said that a good deep well water often does not 

 absorb more oxygen from the permanganate solution (in 

 four hours at 27' C.) than o'ooi grm. per 100,000. 

 Surely such deep well waters must be very exceptional. 



A sample of upland surface water is given with o'o7 of 

 free ammonia, o'2 of albuminoid ammonia and o'i2 of 

 oxygen absorbed, and with total solids amounting to 

 2'8 in parts per 100,000, and one of subsoil water with 

 free ammonia o'i2, albuminoid ammonia 0-033, and 

 oxygen absorbed o'52, without any indication of the fact 

 that these waters are grossly polluted. 



Part 3 also deals with the analyses of sewage, sewage 

 effluents and food. In examining sewage, the student is 

 advised that it often happens when 10 or 20 c.c. of 

 sewage are added to 500 c.c. of ammonia free water, 

 that twelve or fourteen Nessler glasses of distillate are 

 collected before the yield of albuminoid ammonia ceases. 

 This is surely a singular experience. Working at such 

 dilutions and under the directions given by the author, 

 it would be extremely rare that more than five or six 

 Nessler glasses would be required ; moreover, fourteen 

 Nessler glasses would hold 700 cubic centimetres of 

 distillate, and how is the student to collect this from 

 only some 500 cubic centimetres of liquid in the boiling 

 flask ? 



On the subject of food analysis we are informed that 

 analysts of repute obtain the specific gravity of milk by 

 weighing with the specific gravity bottle. If this is so, 

 surely there must be iew analysts of repute in this 

 country. The average amount of water in butter is put 

 at 8'55 per cent., which is too low ; and it is stated that 

 no butter should be condemned as adulterated with water 

 unless it contains less than 80 per cent, of fat ; whereas 

 the limit of water accepted by the Society of Public 

 Analysts is 16 per cent. It is said that " in a normal 

 sample of bread there is as much alum as silica," and 

 that "the weight of silica found must therefore be de- 

 ducted from the amount of alum found, and any excess 

 will represent added alum." As a matter of fact alum 

 is never found in pure bread, nor is it correct to state 

 that there is as much alumina as silica in normal bread. 



That the alcohol of wme and beer is determined 

 e.xactly as in the case of spirits is a bald statement the 

 insufficiency of which will be manifest to the student 

 when, for instance, he first essays an estimation of the 

 alcohol in beer. Doubtless by a printer's error " the 

 Sinaitic Peninsular" is referred to on p. 152, while the 

 atomic weight of silver is given as 1077 on p. 191, and 

 as loS'o in the appendix. 



It must be said, then, that the volume is on the whole 

 an unsatisfactory cne, in which most of the subjects are 

 dealt with, not only inadequately, but sometimes faultily, 

 owing to the attempt to compress too much matter into 

 too small a space. 



NO. I 65 I, VOL. 64] 



The subjects of bacteriology, public health, chemical 

 work, physics and vital statistics have, as a matter of 

 fact, all been dealt with in practical manuals in such a 

 manner that the serious student will not find much use 

 for the book under review. 



PUBLIC WATER-SUPPLIES. 

 Public Water-Supplies : Requirevients, Resources, and 

 the Construction of IVorks. By F. E. Turneaure, C.E., 

 and H. L. Russell, Ph.D. Pp. xiv + 746. (New York: 

 John Wiley and Sons, 1901. London : Chapman and 

 Hall, Ltd.) 



WATER-SUPPLY is unquestionably one of the most 

 important branches of civil engineering in the 

 present day, owing to the widespread nature of the de- 

 mands for It, the great value attached to a pure supply, 

 resulting from the progress of sanitary science, and the 

 increasing difficulty, in populous countries, of obtaining 

 an unpolluted and adequate supply. This book has been 

 prepared with the object of supplying the needs of 

 teachers and students in technical schools ; and the 

 greater portion of it is based on the experience of the 

 first-named author in teaching the subject for many years, 

 which forms one branch of his courses of lectures in the 

 University of Wisconsin. A novel feature in this volume 

 is the conjunction of an engineer and a chemist in its 

 production, thereby enabling the engineering and bacter- 

 iological aspects of the question to be dealt with respec- 

 tively by very competent experts ; whilst a chapter on 

 pumping machinery is 'contributed by another engineer. 

 Fundamental principles have been given more promin- 

 ence than details of construction, though these latter 

 have been largely made use of to illustrate the principles 

 involved and dift'erences in the conditions, and a con- 

 siderable space has been devoted to the quality and puri- 

 fication of water-supplies, constituting such important 

 considerations from a sanitary point of view, and also to 

 the questions connected with ground-water. The com- 

 prehensive scope of the book, and its exhaustive, though 

 concise, treatment of the subject are most effectively 

 illustrated by a reference to the headings of the twenty- 

 nine chapters into which the book is divided. 



The subject is opened by an introductory chapter 

 giving a very brief historical sketch, from the earliest 

 times, of the development of water-supplies, and a state- 

 ment of the value and importance of a public water-supply 

 for domestic, commercial and public uses. The book is 

 then divided into two parts, the first dealing with " Re- 

 quirements and Resources," and the second with "The 

 Construction of Water- Works," in nine and nineteen 

 chapters respectively. The first part is subdivided into 

 two sections, with the respective headings, "Quantity of 

 Water Required : Sources of Supply," and " Quality of 

 Water-Supplies," occupying six and three chapters re- 

 spectively. The first section comprises the quantity of 

 water required, sources of supply, rainfall, evaporation 

 and percolation, flow of streams, and ground-water ; 

 whilst the second section deals with the examination of 

 water-supplies, the quality of water, and communicable 

 diseases and water-supplies. The second part of the 

 book, which is devoted to construction, after two intro- 

 ductory chapters dealing with generalities pertaining 



