MECHANICAL AND USEFUL ARTS. 31 



is, in which case will the capability of increase sooner reach its 

 limits ? 



"Ships which are cumbered by the weight of enormous plates are so 

 overburdened, that they are unlit to carry a broadside of guns heavy 

 enough to penetrate the armour of vessels plated similarly to them- 

 selves. 



"Again, a ship constructed to carry very thick plates, cannot be 

 driven at the high speed which must hereafter give the superiority in 

 naval warfare. 



"There yet remains the consideration of cost. It is true that the 

 richest nationcan bestendure thedrain of costly equipments, andthere- 

 forecheap warfare would be a disadvantage ; but it is also true that 

 naval casualties and mishaps must be calculated upon, and it would 

 be bad policy to concentrate too large an outlay upon a single vessel. 



" It will be for naval authorities to consider the position in which 

 the large, heavily-plated, yet still vulnerable ship would be placed if 

 attacked by several smaller and far swifter vessels, each carrying a 

 few powerful guns, and able to choose its distance for striking an 

 enemy which presents so large a target. "What would be the) result 

 of firing flat-fronted shots at her plates below the water-line, or of 

 their concentrated fire directed upon the axis of her screw — a mark 

 that might be hit at a considerable distance ? 



' ' The plan of warding off shot by protecting armour has been often 

 resorted to, but the means of attack have continually proved the 

 vulnerability of the armour, and driven it out of use. It has to be 

 shown whether this will be the case with our ships of war, and I 

 fully concur in the opinion expressed in your paper — that the best 

 and speediest mode of arriving at a right decision is to give full 

 publicity to the results of properly conducted experiments.' 



Mr. Lynall Thomas, author of a treatise on "Rifled Ordnance," 

 and the inventor of the great gun which has thrown a shot 

 weighing 174 lbs. nearly six miles, has also addressed a letter on 

 Iron-cased Ships of War to the Times, from which we take the fol- 

 lowing remarks : — 



"Those persons who have agreed in favour of the construction of 

 these vessels have done so, I believe, from a limited knowledge of 

 the effect which can be produced by heaVy rifled cannon, Mr. Whit- 

 worth's 80- pounder, the largest hitherto constructed, showing results 

 little, if at all, superior to those produced by a 68-pounder service 

 gun ; while, if we may judge from the letter of an Artillery officer, 

 which recently appeared in the Mechanics' Magazine, all Armstrong 

 guns of a larger size than 40-pounders are unsafe. Notwithstanding 

 that my opinion may be opposed to that of many naval officers of 

 great weight and experience in their profession, I am nevertheless 

 convinced that an iron-cased ship (unless her plates were of a thick- 

 ness utterly to preclude the possibility of her being a sea-going ship) 

 might be destroyed from shore batteries, large frigates, or gun-boats 

 at distances at which she could be hit with any degree of certainty, 

 say two or three thousand yards, and with guns very little, if at all, 

 heavier than the service 68-pounder gun. If Government will find 



