432 



NA TURE 



\March 12, il 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers of rejected manuscripts. 

 No notice is taken of anonymous communications . 



[The Editor urgently requests correspondents to keep their letters 

 as slwrt as possible. The pressure on his space is so great 

 that it is impossible otherwise to insure the appearance even 

 of communications containing interesting and novel facts,] 



The Relative Efficiency of War Ships 

 I have a complaint to make against certain of the statements 

 made in the article upon "The Relative Efficiency of War 

 Ships," which appe ared in your number for February 26. It is 

 incorrect to declare that I advocated before the Committee on 

 Naval Designs, in 18 71, the system of construction upon which 

 the ships of the Adm iral class are built. The Ajax, Agamemnon, 

 Colossus, and Edinburgh are designed upon a citadel system 

 which I originally devised and advocated under certain limita- 

 tions ; but I deny, and always have denied, that any of those 

 ships conformed to the fundamental and indispensable condition 

 which I laid down as part of my system : viz. that the armoured 

 citadel should be of ample dimensions to command the whole 

 structure, keeping it afloat and upright, notwithstanding any 

 amount of injury to the unarmoured ends. As this system has 

 been violated in all the four ships above-mentioned, it is most 

 unfair and improper to state that even those vessels are con- 

 structed upon a system which I advocated. But as regards the 

 ships of the Admiral class they do not at all conform to the 

 system which I advised, and the writer of the article in question 

 could only have supposed them to do so from a serious misappre- 

 hension of the ships themselves. The article stated that the central 

 part of all the ships in question, including the Admiral class, are 

 " plated completely around with very thick armour, which ex- 

 tends from the upper deck to several feet below the water-line." 

 This is a very incorrect description of the Admiral class, the 

 armour in which does not rise to the upper deck at all, but is 

 stopped in the form of a shallow belt rising but a foot or two, 

 or possibly slightly more, above the water's surface. I repu- 

 diate with indignation the statement that such a system of con- 

 struction as this, in association with the long unarmoured ends 

 of the Admiral class, was ever recommended by me. For this 

 reason I complain likewise of the statement in your article to 

 the effect that my recent letter to the Times is but a continuation 

 of the old and well-remembered Inflexible debate. So far is 

 this from being so, that I distinctly pointed out in that 

 letter that the cutting down of the armour to a mere belt 

 of short length separated the ships of the Admiral class from 

 the others, and imported "a new and terrible cause of 

 danger." Another statement of which I complain, and 

 which I desire to have corrected, is to the effect that I 

 " refused to give evidence " before the Inflexible Committee. 

 Were this true, it would constitute, in my judgment, a most 

 serious ground of complaint against me, but it is not true. The 

 Inflexible Report and its Appendices clearly exhibit the fact that 

 within two days of the appointment of the Committee, and on 

 the very day on which my evidence was asked for by the Com- 

 mittee, I handed in to that body a most elaborate mass of 

 evidence, occupying no less than eighteen columns of the In- 

 flexible Report, and illustrated by two sheets of drawings, this 

 evidence setting forth in great detail my views of the subject, 

 and the grounds of my dissatisfaction with such ships. It is 

 true that four months later I was asked by telegram to attend the 

 Committee, but asked to be excused on the ground that I ob- 

 jected to take part in the dilatory proceedings of the Committee, 

 which I regarded as frustrating the objects with which it was 

 demanded by Parliament. My full evidence was, however, 

 already before the [Committee, and had been for several 

 months. 



The above are the points of which I complain, and wish 

 to have corrected. I do not ask as a matter of right, but I 

 desire to have stated, that the long explanation which was 

 given in the article in question for the purpose of showing that 

 mere displacement is not, under alb circumstances, a measure 

 of the power of a ship, was, in my opinion, wholly unneces- 

 sary — at any rate, in so far as either Mr. Barnaby or myself 

 was concerned. Both Mr. Barnaby and myself knew perfectly 

 well that displacement is but a very rough measure of the 

 power of ships, and no measure at all when ships of wholly 

 different classes, and kinds, and dates, and systems are closely 

 compared together. The only use that I made of the principle 

 in my letter was to accept it for the moment as a rough basis 

 of comparison between the ten latest French and the ten latest 

 English ships, and I consider that for that purpose it was a 

 good enough principle to indicate the inferiority of the English 

 ships. But the acceptance of the principle for that purpose in 

 no way precluded me from going further and showing that this 

 rough comparison did not by any means bring to light other 

 elements of grave inferiority, and even of danger, in the 

 English vessels. 



In the accompanying diagram the great difference between 

 the Inflexible or Agamemnon class and the ships of the Admiral 

 class is clearly illustrated. In both figures that part of the 

 armour which is above the water is shown in full black, the part 

 below the water being indicated by dotted lines. A glance at 

 the diagram is sufficient lo make it readily understood that the 



Agamemnon 



Collingwood 



Agamemnon, whose side armour rises several feet above the 

 water, can be inclined to a considerable angle before her 

 armour is brought under the water, whereas a very slight 

 inclination only is necessary to bring the extremely shal- 

 low armour of the Collingwood under the water. In the 

 case of the Agamemnon, therefore, the armour she poss- 

 esses affords her a considerable amount of resistance to 

 capsizing, while the resistance thereto derived by the Colling- 

 wood from her armour is almost nil. The same remark applies, 

 of course, to the buoyancy of the armoured out-of-water parts of 

 the two ships, the Collingwood having but a small fractional 

 part of that which the Agamemnon possesses. 



E. J. Reed 



[We give insertion to this communication from Sir Edward 

 Reed with great pleasure, because one of the chief objects we 

 sought in our article was to support his view that the stability of 

 the ships of the Admiral class under the conditions which might 

 be expected to occur in a naval engagement was open to grave 

 question, and to reassert that further scientific experiments 

 should be made. 



We regret that the fundamental difference, so far as fighting 

 stability is concerned, between ships of the Inflexible and Admiral 

 type, which is now brought out so well by Sir E. J. Reed's 

 diagrams, was not emphasized in the article so strongly as it 

 should have been. — Ed.] 



