138 



NA TURE 



{June 6, 1878 



perspicuity with which this chapter is written are remark- 

 able, and prove the fitness of the author for the work he 

 undertook. Diagrams are given wherever they would 

 serve to assist the reader in readily apprehending the 

 subject. The second chapter is devoted to tonnage 

 measurement, and, while mainly derived from an article 

 contributed by the author to Naval Science (a periodical 

 which is no longer published), it embodies all that naval 

 officers need know upon the subject, including the 

 measurement of yachts, and the regulations of the Suez 

 Canal ; these latter, we regret to say, are in some respects 

 carried out at present in violation of the understandings 

 which were come to with the British Government, and were 

 announced as authoritative by our Ministers in Parliament. 

 The third chapter is an admirable statement of the prin- 

 ciples which regulate the statical stability of ships — a 

 subject upon which Mr. White well deserves to be pro- 

 nounced a high authority, and one who has worthily 

 extended this branch of science.' This chapter, like 

 some later ones, embodies information which the naval 

 architect would do well to study, more especially as 

 regards the effect upon stability of adding, shifting, and 

 removing weights. At p. 63 the author remarks that the 

 question of neutral or indifferent equilibrium has little 

 practical interest in connection with ships, "for which 

 stability and instability are alone important." However 

 true this may have been a short time ago, it is no longer 

 so, for the case of the Itiflexible has invested the question 

 of infinitesimal stability, and of neutral equilibrium, with 

 a strong and melancholy interest, and an interest which 

 must go on increasing if such ships are repeated. The 

 investigations of the Liflexibl^s state led the writer of these 

 lines to observe and consider a peculiar condition of 

 stability which may, and doubtless will, arise in citadel 

 ships like the hiflexible, with unarmoured ends large in 

 proportion to the citadel, and which would add a curious 

 case to the numerous curves of stability v/ith which this 

 chapter is illustrated. It is the case in which the citadel 

 is so formed and proportioned, that the ship, with her 

 ends penetrated, would have no stability in her upright 

 position, but would acquire a small amount on inclining 

 through a greater or less angle, and lose it again on being 

 inclined still further. This case would exhibit itself in a 

 curve of stability by a mere loop, of greater or less length 

 and depth, and at greater or less distance from the origin, 

 according to circumstances. A similar result would of 

 course arise in any ordinary ship, the statical stability of 

 which was nil in the upright position, but become positive 

 at an inclination. We mention it here, however, because 

 in the case of a citadel ship it reduces to an absurdity, and 

 to Avorse than an absurdity, that reference to " range " of 

 stability Avhich has been much too frequent in recent 

 discussions. In a future edition Mr. White would do well 

 to extend his remarks upon this branch of the subject, as 

 it has become one of great practical, and even of vital 

 interest. 



The following chapters, on the Oscillations of Ships in 

 Still Water, on Deep-Sea Waves, the Oscillations of 

 Ships among Waves, and Methods of Observing the 

 Rolling andPitching Motions of Ships, together form a 



' By a valuable paper " On the Calculations 'of the Stability of Ships," 

 read at the Institution of Naval Architects in 1871, the joint production of 

 Mr. White and Mr. W. John, now of Lloyd's Register Office, and by other 

 contributions to the- knowledge of this subject. 



most valuable treatise on a branch of naval science which 

 is both in form and substance essentially modern, and 

 full both of interest and of future promise. Although 

 this part of the work has necessarily been composed 

 chiefly by compilation, it is the result of much labour, 

 and of a close study of a large number of essays and 

 discussions which have appeared from time to time 

 during the last eighteen years. In the first paper ever 

 read (in i860) at the Institution of Naval Architects, Dr. 

 WooUey said — "One of the chief benefits to be looked 

 for from the Institution which we are inaugurating to-day 

 is a more systematic inquiry into the laws of nature on 

 which the motions of a vessel at sea depend than has 

 hitherto been attempted." These were prophetic words, 

 for the field of labour to which scientific men were thus 

 invited was very soon entered upon by Mr. Froude, who 

 has most worthily and successfully laboured in it ever 

 since. He has been joined by other labourers who 

 have well and steadily advanced the good work, in- 

 cluding several able French savans (notably M. Berlin, 

 of Cherbourg, and M. Duhil de Benaz^), and most 

 recently Dr. WooUey himself, who a month since con- 

 tributed to the same institution a most able analytical 

 discussion of the constitution and properties of deep-sea 

 waves. No summary of the recent striking developments 

 of science respecting the constitution of sea waves, and 

 the behaviour of ships among them, which can at all com- 

 pare with that here" given by Mr. White can anywhere be 

 found. 



The following chapter on the strains experienced by 

 ships is an equally clear and comprehensive statement of 

 another thoroughly modern branch of study. It is 

 primarily based upon a paper published in the Philo- 

 sophical Transactions by the present writer in 1 871, in 

 the calculations and construction of which Mr. White 

 largely co-operated. The methods of investigation pur- 

 sued were novel, and of so detailed a nature as to place 

 the subject on a solid basis of fact, with the result of either 

 setting aside or subverting most of the opinions — for they 

 were but opinions — which had previously prevailed. The 

 present author gives the substance of those labours, and 

 adds to them the results of many others of more recent 

 date, supplementing the general investigation with brief 

 examinations of minor and local strains. The chapters 

 on the structural strength of ships and materials for ship- 

 building, although of less immediate value to naval officers 

 than those that illustrate the behaviour of ships in motion, 

 abound with facts which they will find of daily value 

 afloat. In places the author is somewhat more historical 

 and diffuse, perhaps, than is strictly consistent with the 

 object of the work, but all that he records is valuable, and 

 the narrative passages will doubtless add to its attractions, 

 especially in the eyes of the younger officers. With re- 

 spect to the important question of the "Resistance of 

 •Ships " (so designated, as usual, although "Resistance to 

 Ships ' ' would surely be more correct) the author has per- 

 formed a like service to that rendered in the case of 

 the recent discoveries respecting waves and the oscil- 

 lations of ships. He has sketched and summarised the 

 existing knowledge of the subject, and here as elsewhere 

 has kept mere abstract considerations and theories well 

 under the control of practical requirements. He has done 

 justice to the recent labours of Mr. Froude in this sphere 



