290 



NATURE 



[July 28, 1892 



oedema, which is an anaerobic organism. Though it 

 resembles the bacillus of grouse disease in certain 

 respects, they are not to be regarded as one and the 

 same microbe. 



The second part of the book contains an account of 

 a fatal epidemic amongst fowls which broke out at 

 Orpington in Kent. The symptoms and post-mortem 

 appearances led Dr. Klein to designate the disease fowl 

 enteritis, in order to distinguish it from fowl cholera. 

 The bacillus which is the cause of fowl enteritis is not 

 identical with the bacillus of fowl cholera, and Dr. Klein 

 clearly proves this. 



Dr. Klein's bacillus is evidently a less virulent organ- 

 ism. In only one case was the disease produced by feed- 

 ing fowls with the intestinal contents of a diseased fowl. 

 Experiments on other animals gave practically negative 

 results, except in the case of one rabbit. The virulence 

 of the bacilli was lessened by heat. Fowls inoculated 

 with this attenuated virus could not be infected with the 

 disease. Some practical suggestions are given with a view 

 to combating such epidemics. 



The concluding chapter of the book contains an inter- 

 esting account of a disease in young pheasants known as 

 " Cramps." 



We have given but a very brief account of Dr. Klein's 

 important investigations. The book will, however, be read 

 by every one interested in the subjects of which it treats, 

 and with great profit. To other workers in the same field 

 it will prove an indispensable work of reference. We 

 have only detected one misprint, on page 53, where 

 *' 50° Fahr." should no doubt have read 5o°C. 



We cannot close this notice without a word of praise 

 for the excellent photograms of Mr. Pringle and Mr. 

 Bousfield. A. M. 



ELECTRIC LIGHT CABLES. 

 Electric Light Cables. (London : Whittaker and Co., 

 1892.) 

 A DOZEN years ago, when dynamos and lamps, both 

 -"-*- arc and incandescent, had been pretty well 

 developed, the general public arrived at the conclusion 

 that it was time to commence the work of central station 

 lighting by electricity. It was not until the plans of these 

 proposed works were taken in hand by the consulting 

 engineers that the difficulties in the way of distribution 

 became fully apparent. It was not well known what 

 strength of current could be safely carried through the 

 conductors ; and engineers were rather appalled at the 

 cost of the copper required for maintaining uniform 

 pressure over a district, and at the waste of energy in the 

 condu(;tors. Besides these theoretical troubles in the 

 way, engineers were met by the practical difficulty of 

 devising a secure and efficient means of laying conductors 

 under the streets, and ensuring their proper insulation- 

 Until recently, the rules which must be attended to by 

 engineers to enable them to handle these questions were 

 only to be found in scattered pamphlets and Proceedings 

 of societies. Several scientific men dealt independently 

 with the heating of the conductors, and finally Mr. 

 Kennelly published his splendid experimental work on 

 the subject. Other writers went fully into the economical 

 NO. I 187, VOL. 46] 



principles which must be followed in order to secure the 

 most uniform distribution at the least cost. When the 

 alternating-current rendered the employment of high 

 pressures both safe and convenient, many of these pre- 

 cautions became less necessary, but new problems arose 

 which are also generally dealt with only in isolated 

 papers. Inventors sprang up, each advocating his own 

 system of laying mains, and an outsider can gain a know- 

 ledge of these only by reading the patent specifications, or 

 by inspecting the progress of works. The mechanical 

 details of making joints, insulating, and so forth, are not 

 much dealt with in the literature of the subject. 



The book before us is one of the first attempts to 

 collect all the above principles within one binding. The 

 first few chapters deal principally with the heating of 

 conductors and the economical laws of distribution. 

 Well-known writings on the subject are here condensed 

 into convenient compass, and Kennelly's experimental 

 results are given in sufficient detail. Series and parallel 

 systems and their combinations, including the three-wire 

 and five-wire systems, which serve so much to economise 

 copper, are explained, and also the principles involved in 

 the use of transformers with alternating currents. Having 

 thus described the systems available, we have, in 

 Chapter v., a useful account of the cost of cables and 

 conduits, with tables showing the relative cost of different 

 systems when the distribution extends to different 

 distances, showing the advantages of using high pressure 

 for long distances. Chapter vi. gives a number of practi- 

 cal data about different kinds of conductors and the 

 manner of making joints, which, though not exhaustive, 

 will be of use to many. The next chapters deal with the 

 characters of the insulation, including air insulation, lead- 

 covered cables, the various bituminous compounds known 

 as bitite, &c., oil insulation, and, of course, vulcanized 

 india-rubber, about which the author is particularly 

 capable of giving information. The effects of capacity, 

 which has given so much trouble at some central stations, 

 are also alluded to. These chapters are very fairly 

 written, and give as good an account of the various 

 systems of insulation as is likely to be found anywhere, 

 or as we might expect in a volume of this size, which is 

 more a hand-book of the subject than an exhaustive 

 treatise. Some of the principles of testing are then 

 shortly, but very clearly, described ; and the principles of 

 house wiring are clearly shown, and safety devices 

 described. Several good chapters come near the end of 

 the book on the practical construction of lines, whether 

 overhead or underground, the latter dealing chiefly with 

 the actual work which has been done in London of late 

 years. 



This book is one of the best which could be taken up 

 by the student to give him a general knowledge of what is 

 involved in the comprehensive title — "The Distribution of 

 Electricity." It does not pretend to be a complete manual 

 for the office, containing all the information required by 

 the consulting engineer in dealing with these problems, but 

 the descriptions are clear and generally accurate, and the 

 only criticism which we feel compelled to make is that 

 sometimes, apparently with the desire of preventing the 

 book from being too technical, or requiring too much 

 mental effort to read it, the author has been, perhaps, a 

 little too sketchy, and might with advantage have given 



