But the net register tonnage will be ascertained by making certain allowed deductions, which include the space taken up for propelling power, the quarters of the crew, and of the captain, as well as the chart-room, the boatswain’s store-room, and the water-ballast spaces. As instancing the curious results which are obtainable from the different measurements for reckoning tonnage, Mr. A. L. Ayre, in his “British Shipbuilding,” gives the interesting comparison of a particular steamship according to her varying tonnage. Thus the ship in question has an under-deck tonnage of 550, whilst her gross tonnage worked out at 980, and her net register tonnage at 360. It is not generally known perhaps that the complicated system of arriving at the net register tonnage gives opportunity for strange and amusing effects. Owing to the difference between the actual engine-room in a steamer and the theoretical engine-room, it is not only possible to build a ship with a negative tonnage, but this has actually occurred in the case of a certain tug, and was referred to in the report of the Royal Commission on Tonnage, 1881. The present writer was recently aboard a new 20-ton yacht, in which the owner had been fortunate enough to persuade the authorities to get the measurements down so low that the net register tonnage came out at a ludicrously low figure. Internally, nothing was more conspicuous than her roominess, which was of a quite exceptional character. The vessel was a two-masted sailing craft, but supplied also with an auxiliary motor, which did not detract from the roominess of the ship, since it was placed out of the way underneath the companion ladder. However, by the time the deductions had been made for “engine-room” space, “chart-room” (which was really the comfortable and spacious main cabin), and sundry other items, the size of the yacht had theoretically shrunk from 20 tons to something almost insignificant, and the consequence was that this bold vessel was able to escape with harbour dues as low as yachts of one quarter of her own tonnage. Not long since a humorist saw fit to write an amusing yarn, in which he depicted a certain individual who, smarting under what he believed were excessive harbour dues, determined at length to get even with the authorities, and finally had built a steam vessel rather on the lines of the screw tug than the usual steam yacht. Roominess was not the owner’s objective; all he wanted was just as much space for himself as was comfortable. But he sub-divided the rest of the ship into a large space for her engines and boilers, as well as auxiliary engines to drive capstans, together with a roomy forecastle for the crew. His own cabin was clearly marked on the plan as “Captain’s Cabin.” Finally, after the vessel was launched, and the internal capacity of the hull, as well as the spaces occupied by the machinery and the crew, had been deducted so as to obtain the net register