We have already shown during the progress of our story how the use of tanks has gradually been employed in the ballasting of the steamship. Not merely is the double bottom used for this purpose, but, as we mentioned, tanks are placed between decks in the wings in certain ships. Although a steamship, when her double bottom tanks have been filled, becomes much stiffer and possesses a greater displacement, yet she will certainly roll more heavily, and so tend to cause heavy strains in bad weather. Many vessels possess also tanks both in the fore-peak and the after-peak, which are extremely useful for the purposes of modifying the trim of the ship. This is especially valuable when the ship is proceeding “light,” and has not the advantage of a weighty cargo on board to keep the propeller well immersed. At the same time, supposing that the after-peak tank were utilised for the purpose of immersing the stern to a greater extent, it would also follow that the bows would be raised fairly high above the water, and in the case of a beam wind, the ship would not be easy to handle, for her head would have a strong tendency to fall off in just the same way as the man in the Canadian canoe seated at the stern finds that considerable difficulty is met with in steering his little craft with her bows out of the water, and at the mercy of every puff of wind which may blow from either side. As in other respects the ship is a compromise, so in regard to stability. She has to be stiff, or else she will roll right over in a sea-way; yet she must not be too stiff, or she will roll badly, and perhaps do herself serious harm, quite apart from being extremely unpleasant to those who happen to be aboard. Therefore, the aim nowadays is to give the ship a reasonable amount of stability, and to cause her rolling in a sea-way to be of an easy character. This is brought about by additional ballast tanks, which not only give the ship greater immersion and displacement (so causing greater stability), but by raising the centre of gravity through placing additional ballast in those ’tween-deck wing tanks that we discussed when we were considering the cantilever ships, the tendency of the vessel to roll is minimised. In fact, the combination of the double-bottom tanks and the wing tanks takes away excessive stiffness and heavy rolling, and makes the ship to behave in an easy manner in bad weather, even without cargo on board. Then, again, since salt water is more buoyant than fresh, it will follow that when a ship passes from the sea into fresh water, her draught will be increased, and, therefore, there will also be a decrease in the amount of freeboard above the water-line, and, consequently, the range of stability becomes less also.