598 



'NATURE 



[October 15, 190S 



numbers are classified under the heading " Other 

 Special Sorts of Complex Numbers," while the older 

 papers are properly classified under the heading 

 "General." Again, Hamilton groups are classified 

 under " Quaternions," and not as one would expect 

 under " Groups." Occasionally the subdivision of 

 headings is carried so far as to be a hindrance in- 

 stead of a help. For instance, references to papers 

 on matrical equations are scattered over five separate 

 headings, instead of being under one heading with 

 two or three subheadings. Several short notes also 

 have been omitted which might well have found a 

 place. A short note appearing early in the develop- 

 ment of a subject is of more importance than a 

 similar one appearing at a later stage. If it was 

 impracticable to classify all such notes minutely, they 

 might have been given under the main headings with- 

 out any subclassification. 



Another difficulty which is likely to occur now and 

 again in the use of the Index is that occasionally 

 short papers are published for the first time in the 

 collected works of an author. Such papers are not 

 classified in the Index, which only includes periodicals 

 in its list. In the case of matrices, too, several in- 

 teresting accounts of the subject have appeared as 

 appendices to treatises having no direct connection 

 with this subject except in so far as matrices are 

 required for some portions of the analysis. Such 

 articles are of course not indexed, although thev are 

 sometimes of some importance. 



Such criticisms of detail might no doubt be carried 

 much farther; they affect, however, only points of 

 comparatively small importance, and do not affect 

 materially the great service which the Index will 

 render to the mathematical public. At a moderate 

 estimate it will lessen the labour of forming biblio- 

 graphies, or of hunting up references, by consider- 

 ably more than one-half. An exceedingly useful 

 feature of the work is a list of periodicals which 

 gives the names of the principal British libraries in 

 which they are to be found. This should effect a 

 great saving of time for those who are not so fortu- 

 nate as to be situated close to any of our principal 

 libraries. 



The Index is published by the Cambridge 

 University Press, and, as is usual in books published 

 by them, the printing leaves nothing to be desired. 



MODERN MARINE ENCI.XEERING. 

 Marine Engineering (a Text-Book). By Engineer- 

 Commander A. E. Tompkins, R.N. Third edition, 

 entirely re-written, revised, and enlarged. Pp. viii 

 + 812. (London: Macmillan and Co., Ltd., 1908.) 

 Price 15X. not. 



1\/[-M^lNE engineering has been developed in 

 •1-' J- many directions during recent years, and the 

 influence of these developments upon the design of 

 steamships has been marked. Within a period of 

 fifteen or sixteen years water-tube boilers have prac- 

 tically taken the place of cylindrical (or " tank ") 

 boilers in all classes of warships ; steam-turbines have 

 been introduced for ship-propulsion, and have already 

 superseded reciprocating engines in the Royal Navy, 

 NO. 2033, VOL. 78] 



while growing in favour in other war-fleets and in 

 mercantile steamships ; oil-fuel has been adopted as 

 a supplement to or substitute for coal; and now 

 internal-combustion engines are being introduced and 

 greatly increased in size and power. It is a natural 

 consequence of these changes that numerous addi- 

 tions should be made to the literature of the subject, 

 and that new editions of standard text-books should 

 appear. 



Among these text-books, intended primarily for 

 the use of students, the work under review holds a 

 distinguished place. The author is an experienced 

 engineer officer of the Royal Navy, who has served 

 long at sea in charge of machinery, and has also 

 been occupied for some time as instructor and lec- 

 turer in marine engineering at the Royal Naval 

 College, Greenwich, and the Royal Naval War Col- 

 lege. .At both these establishments he had to do' 

 chiefly with naval officers, whose technical knowledge 

 of engineering was much the same as that of 

 students beginning work on the subject. He has 

 consequently given explanations of both theory and 

 practice in simple language, which makes the book 

 serviceable, not only to students of marine engineer- 

 ing, but to general readers desirous of obtaining 

 acquaintance with modern methods and the most 

 recent designs of marine engines and boilers. This 

 third edition is virtually a new book — re-written and 

 considerably larger than its predecessors — bringing 

 information up to date. It deals briefly with types 

 of boilers and machinery which have been made 

 obsolescent by the progress of recent years, and aims 

 at the presentation of " a summary of the best prac- 

 tice of the present day." It is but justice to the 

 author to say that this intention has been realised. 



The theory of thermodynamics is treated in an 

 elementary manner, and its applications to the forma- 

 tion and expansion of steam are explained. One 

 section is devoted to marine boilers, and the various 

 types of water-tube boilers now in use are fully de- 

 scribed. Another section treats of combustion, giving 

 details of the methods adopted for efficiently burning 

 coal and liquid fuel, and particulars of the various 

 kinds of liquid fuel now in use. The conclusions 

 reached by the author are that, for a given weight 

 of coal and oil, oil gives from 25 to 30 per cent 

 greater energy, reduces the space for stowage bv 

 10 per cent., makes it much easier to replenish fuel- 

 supplies, and decreases the number of firemen by 50 

 per cent. The determining factor in regard to the 

 extended use of oil-fuel is now, as it has been for 

 the last twelve years, the question of adequate sup- 

 plies at reasonable rates. Reciprocating engines still 

 hold the field in the mercantile marine, and are de- 

 scribed at length in their latest forms. Condensers, 

 evaporators, feed-water systems, superheaters, and 

 other accessories also come under review ; and so does 

 auxiliary machinery of various kinds — including 

 steering and capstan engines, refrigerating apparatus, 

 air compressors, hydraulic machinery, electrical appa- 

 ratus, and other classes of machines, all of which 

 are essential to the efficient working of a modern 

 steamship. The care and management of propelling 



