February i6, 1899] 



NA TURE 





of 



competitors with a painful number of illustrations 

 methods of how not to teach technical chemistry— 

 illustrations of the very highest (negative) value. It is 

 often, and justly, urged by the critics of our educational 

 methods that we are the slaves of the examination system. 

 But there is another demon that has come into our midst 

 of late years, which also wants e.xorcising— the statistical 

 demon. The committees of most of our educational 

 establishments seem to have the one idea that success is 

 measured by numbers of students turned out. The fol- 

 lowing statement, by Prof. Naumann, might profitably be 

 stereotyped into an aphorism for the use of some of our 

 technical instruction committees and kindred bodies :— 



" Der deutschen chemischen Industrie kommt es nicht 

 aufdieZahl der gelieferten Chemiker an, sondern auf 

 ihre Qualitat." 



In concluding this notice, it is difficult to refrain 

 from instituting a comparison between the methods 

 adopted by the Germans and ourselves for dealing with 

 the same problem of foreign competition. Instead of 

 catering for the highest kind of work, and aiding existing 

 teachers and institutions to do such work, we seem to 

 prefer adopting a policy of broadcast smattering. If any 

 bold advocate points to signs of decadence in any parti- 

 cular industry, the statistical juggler is always at hand to 

 prove that he is mistaken. When we have achieved 

 supremacy in any department and meet with competi- 

 tion, the educational machinery is the last line of our 

 defence which is strengthened instead of being, as in 

 Germany, the first. That we have been enabled in the 

 past to achieve eminence without technical education is 

 sometimes even now used as an argument that technical 

 education is unnecessary. Our chemical manufacturers 

 will do well to take Dr. Fischer's pamphlet, and the 

 lesson which is contained therein, as a very serious sign 

 of the coming struggle. So far as organic chemical 

 products are concerned, the e.xpression " made in 

 Germany " is one of which that nation may now well 

 be proud. R. Meldola. 



SEWAGE PURIFICATION AND SEWERAGE. 



The Purification of Sewage; being a brief Account of the 

 Scientific Principles of Sewage Purification and their 

 Practical Application. By Sidney Barwise, M.D. 

 (London), M.R.C.S., D.P.H. (Camb.), Medical Officer 

 of Health to the Derbyshire County Council. Pp. xii 

 -fi5o. (London : Crosby Lockwood and Son, i8g8.) 



Sewerage. The Designing, Construction, and Mainten- 

 ance of Sewerage Systems. By A. Prescott Folwell, 

 American Member Society of Civil Engineers. First 

 Edition. Pp. x + 372. (New York : John Wiley and 

 .Sons. London: Chapman and Hall, Ltd., 1898.) 



THE question of the hour is — What steps are to be 

 taken for the disintegration of sewage without the 

 addition of chemicals? Going a little outside this. Dr. 

 Sidney Barwise has collected a certain amount of inform- 

 ation which he thinks may be useful to his fellow medical 

 officers of health. He points out that during recent 

 years 



" great advances have been made in our knowledge of 

 the changes which sewage undergoes in purification, and 



NO. 1529, VOL. 59] 



not a few conclusions of wide-reaching importance estab- 

 lished ; and it is hoped that the presentation in this little 

 work of some of the results thus obtained will be found 

 useful by engineers and others, officials who wish to avail 

 themselves of the latest researches of chemists and 

 biologists upon the questions of sewage purification." 



Although the work may be said in a certain sense to 

 be an elementary text-book, it is something more, as the 

 author has collected in handy though somewhat sketchy 

 form a number of the more important observations on 

 the chemistry and bacteriology of the decomposition of 

 sewage. After describing sewage, its varieties, the 

 changes that it undergoes, and its chemistry. Dr. Barwise 

 indicates the effects of river pollution and the processes 

 by which the water becomes purified ; he goes on 

 to give an account of "land treatment" of sewage, of 

 precipitation, precipitants, and tanks, filtration or nitrifi- 

 cation ; and then describes in detail some of the special 

 forms of sewage filters, especially Mr. Dibdin's filter, used 

 in the experiments carried on by the London County 

 Council ; Colonel Ducat's filter, Garfield's coal filter, the 

 Lowcock filter, and the Scott MoncriefF and Cameron 

 filters. 



Perhaps the most important feature of this work is that 

 in which the author has attempted to compare the 

 different sewages with which various experiments have 

 been carried on in this country and in America. There 

 can be little doubt that this question of comparative 

 composition of sewage is one of great importance in 

 determining what the various processes are capable of 

 achieving, and therefore which process is best fitted for 

 use in any special region. Taking the chlorine content 

 as an index of the strength of sewage, it is evident, for 

 example, that very different results would be obtained 

 with any system in which an attempt is made to deal 

 with, say, the Lawrence (Mass.) sewage, which contains 

 43 parts of 100,000 of total solids, and 4'S parts of 

 chlorine ; or the Exeter sewage, with 54-4 parts total 

 solids and 5 parts chlorine; and London sewage, which 

 contains 1235 parts total solids and i5'2 of chlorine; 

 or, again, the Berlin sewage, which contains 2i8'3 parts 

 of total solids per 100,000 and 21 '8 of chlorine. There 

 can be no doubt, however, that with many of the 

 bacteriolytic methods described, remarkable results 

 have been obtained, and statistics are given indicating 

 the amount of purification brought about by each system ; 

 but the author very wisely in his conclusions points out 

 that before it is possible to answer the question, " What 

 processes shall we adopt to purify our sewage ? " there 

 must be information given as to the nature of the sewage, 

 the facilities for disposal of sewage on land, the necessity 

 that may arise for precipitation, the amount and nature 

 of manufacturing waste, and the facilities that exist for 

 complete oxidation of the effluent. The author has taken 

 a considerable amount of trouble to collect trustworthy 

 statistics, and were this part alone before the reader it 

 would be worth reading ; but apart from this, the book 

 contains a considerable amount of information — in some 

 instances loosely put together, and not always sufficiently 

 fully set forth— and, taking the work for what it claims 

 to be, it should prove not only of interest but of assist- 

 ance to those who are engaged in advising sanitary 

 authorities as to what measures it will be necessary to 



