The very low percentage of ordnance seems no doubt strange to many who talk loosely of heavy guns and projectiles without thinking that this element is one of solid dead weight occupying an immense space. From 5 to 7 per cent includes the entire range, from the vessel sacrificing ordnance to speed to the one with a maximum of ordnance and moderate speed, the Duke of Edinburgh being again an exception. The limits of weights of engines and boilers may be placed at from 11 to 13 per cent, and those of the coal supply from 8 to 11 per cent. Great diversity should be expected in the percentages of ordnance, engines, and coal in the second-rates, depending upon their special objects, yet as is seen there is scarcely 4 per cent difference between the extremes. The remaining percentage should be about the same throughout, with a slight variation for the proportion of sail-power, the total allowance for this latter being from 1 to 3 per cent. By means of these tables the beginner may get an adequate idea of the limiting proportions of the main elements of a vessel. It is seen that the factor absorbing the greatest proportion of the displacement is the one that calls for a reduction, all others requiring extension. Weight of hull is an obstacle. In armor, by an increase of percentage an increase of defensive power is gained; with ordnance, an increase of offensive power; with boilers and engines, an increase of general effectiveness; with coal, an increase in endurance; while the percentage of spars, crew, and stores is a necessary constant. Thus the development of naval construction is seen to be a matter of vital importance. Had the Onondaga been properly constructed there would have been a useful percentage of fully 20 per cent to have been distributed in making her a sea-going vessel. This fact is plainly brought out in the breastwork modifications of the monitor type, in which the breastwork is a clear addition of dead weight on a similarly formed and proportioned body without being of any assistance as additional freeboard. From the results attained in the Tegetthoff the lowest limit of weight of hull attainable with present perfections of steel construction may be placed at 34 per cent for first-rate frigates and about the same for second-rates. For turreted vessels it may fall to 28 or 27 per cent.