FRENCH IRON-CLAD SQUADRON. 199 



iron-clad squadron some very forcible conclusions. In certain respects they have 

 already upset the old theory by shewing that the most stable vessel is not that 

 which rolls the least, and even that it may be one ■which has a very lively and 

 distressing roll. The fact is now accepted, at least by the most distinguished 

 sailors, but we may expect a very warm discussion when we assert, as the new 

 theory does, that the number of a ship's rolls is absolutely independent of the 

 state of the sea, and of the greater or less rapidity of succession in the waves ;. 

 that each vessel ought to be considered as a pendutum for which, under a given 

 arrangement of weights there is a certain invariable number of oscillations which 

 is peculiar to itself, and that the intensity and rapidity of the waves do not affect 

 the number but only the magnitude of the rolls ; lastly, that the vessel which 

 compared with others, has rolled the most one day, may be that which will roll 

 the least on the morrow. This is what happens in the case of the pendulum oscil- 

 lating normally, when it meets by chance in the agitation of the sea, a cause of 

 motion concordant, harmonizing with, and isochronous to its own ; the vessel will 

 then astonish by the magnitude of its movements those who the day before, and 

 yet, possibly, in worse weather, but Ici-s sympathetic somehow with her particular 

 constitution, were admiring the gentleness of her roll. 



If these notions are correct — and I repeat there has been observed during the 

 trip a great number of facts in confirmation, and not one in contradiction of them ; 

 — If these notions are correct we see the bearing they have on the question of the 

 roll of the iron-clads. They put the armour itself altogether out of the question, 

 and reduce tbe discussion to bear only on the shape and on the position of the 

 general centre of gravity of the vessel, including hull and loading. The question 

 then being stated in these terms, is it true that the new ships, especially the 

 Magenta and Solferino, which ought to be regarded as developed and perfected 

 copies of the first models of the Oloire, have given in comparison to the vessels 

 with which we are studying them differences in magnitude or frequency of roll, 

 which would constitute in this respect a real cause of inferiority ? No 1 — Such 

 assertions cannot be maintained. Next to the Talisman, it is the Normandie which, 

 of all the ships of the squadron, had the worst roll, and ite example of this frigate 

 will give us a useful lesson. When it was proposed to fit out the Hormandie a 

 report was generally spread, one knows not how or why, that this latter had a 

 very heavy roll, and consequently it was wished to remedy this supposed defect, 

 but opii)ions differed as to the nature of the remedy to be used. Some, and 

 they were the smaller number, asserted that if it were true that the frigate 

 rolled too much, this must be because she. had too great stability, that is 

 to say, that the weight accumulated in the lower part of the vessel was sensibly 

 in excess compared to that above; it was necessary to bring about a better 

 equilibrium by increasing the weight she carried aloft. Others, on the con- 

 trary, maintained that the frigate rolled because she had not stability enougii ; 

 the motion of which she was accused was appealed to as proof of this defi- 

 ciency, and to remedy it they proposed to do exactly the opposite of what 

 the others advised, that is to say, to lighten the frigate above and thus lower her 

 centre of gravity and consequently render her more stable. This last advico 

 gained the day ; the weight of the masts was lessened, and the block-house she 



