is thinned out to a substance of only 4 in., so as entirely to cover the sides of the vessel down to 5 ft, below the water line; this thickness of plating being regarded as sufficient to break up upon its surface the dreaded melinite or guncotton shell, but permitting the passage of armor-piercing projectiles right through from side to side; provision being made to prevent damage from these latter to engines and vitals by means of double-armored decks below, with a belt of cellulose between them.  Thus, as we have explained, two prominent ideas are present in the disposition of armor upon the battleships of Great Britain, as well as in that of the battleships of France.  But, while in our country these two ideas follow one another in the natural sequence of development, from the Inflexible to the Royal Sovereign, the citadel being gradually extended into two redoubts, and space being left between the redoubts for an auxiliary battery—­this latter being, however, singularly placed above the armored belt, and not within its shelter—­in France, on the other hand, we find the second idea to be a new departure altogether in armored protection, or rather to be a return to the original thought which produced the Gloire and vessels of her class.  In point of fact, while we have always clung to the armored citadel, France has discarded the belt altogether, and gone in for speed and light armor, as well as for a much lighter class of armament.  Time alone, and the circumstances of actual warfare, can prove which nation has adopted the wisest alternative.

A glance at the engraving will show the striking contrast between the existing service types as to armored surface.  The Marceau appears absolutely naked by the side of the solidly armed citadel of the Nile.  The contrast between the future types will be, of course, still more striking, for the reasons given in the last paragraph.  But while remarking upon the paucity of heavy plating as exhibited in the service French battleships, we would say one word for the angle at which it is placed.  The receding sides of the great vessels of France give two very important attributes in their favor.  In the first place, a much broader platform at the water line is afforded to secure steadiness of the ship and stable equilibrium, and the angle at which the armor rests is so great as to present a very oblique surface to the impact of projectiles.  The trajectory of modern rifled guns is so exceedingly flat that the angle of descent of the shot or shell is practically nil.  Were the sides of the Royal Sovereign to fall back like those of the Marceau or Magenta, we seriously doubt whether any projectile, however pointed, would effect penetration at all.  We conclude, then, that a comparison of the Marceau with the Nile as regards protective features is so incontestably in favor of the latter, that they cannot be classed together for a moment.  In speed, moreover, though this is not a point under consideration, the Nile has