In ’73 Mr. Barnaby had questioned the wisdom of expending a large weight in the protection of turrets. Three years later Commander Noel, in a Prize Essay, was advocating unarmoured batteries, with a view to multiplying the number of battery guns, utilizing for offence the weight thus saved. In ’73 Mr. Barnaby had argued that the stinting of armour on the hull in order to thicken it on the battery would drive the enemy to multiply his light and medium machine-guns. Within a few years warships were bristling with Gatling and Gardner, Nordenfelt and Hotchkiss guns, which by their presence gave a new value to armour, however thin. Mr. Froude, too, in his experiments in connection with the _Inflexible_, brought into prominence the advantage which thin armour on a ship’s ends conferred on her stability. The idea of substituting cellular construction for armour was proving attractive. While the French continued to favour the complete water-line belt, the Italians went to the limit in the _Italia_ and _Lepanto_, in which the water-line was left entirely unprotected by side armour. Such armour as was carried was embodied in the form of a protective deck, a feature found above water and in conjunction with a side belt in our _Devastation_ class, and under water and without side armour in the _Inflexible_ and smaller contemporary ships. The protective deck, which covered the vitals of a ship and deflected shot and shell from its surface, was a device which found increasing favour with naval architects. It was advocated by the Committee on Designs in ’71 as possessing important advantages over a similar weight of side armour. If placed at some distance below water it formed the roof of a submerged hull structure which was immune from damage by gun-fire, the sides of this hull being protected sufficiently by sea-water. If, as was subsequently done, the protective deck were placed at a small distance above water, and if the sides of it were bent down so as to meet the ship’s sides at a distance below water beyond which a shot was unlikely to penetrate, the deck offered other advantages: the vital machinery, though now partly above water, was still protected, the sloping parts of the deck being able to deflect shots which would have penetrated a much thicker vertical plate; moreover, if the ship’s sides were riddled in action, the protective deck still preserved a large portion of the water-line area intact, and thereby secured her lateral stability.