This cargo-ton, the _tonneau d’encombrement_, was equal to 42 French cubic feet = 51 English cubic feet. The Ton Register appears to have arisen in the ports of Northern Europe. There the unit was usually the skippund (ship-pound) of about 360 lb. for wool and light goods. But the Last was also a wide-spread, though variable, measure; in the Baltic trade it was usually reckoned at 11-1/4 quarters of wheat = 90 bushels or 5400 lb. In England it was usually 10 quarters = 80 bushels = 5000 lb. Now this bulk of wheat measures about 100 cubic feet, so 100 English cubic feet has become the unit adopted in all maritime countries, as the Ton Register. In France it is called the _tonneau de jaugage_ and is taken as = 2·83 cubic metres. A ship of 2000 tons register is of a capacity = 200,000 cubic feet below decks. The register tonnage is thus obtained: Mean length × 0·94 of maximum beam × depth from upper deck to keel, the measure being taken inside, and in feet. The product is cubic feet, which divided by 100 gives register tonnage. In France these measurements have to be made in metres; the product in cubic metres is divided by 0·38 to get tonnage. Net tonnage, as distinguished from gross tonnage, is the latter less the space occupied by cabins below deck, by engines and bunkers, in short all that is not ‘hold.’ This deduction gives the space available for cargo, a very large proportion in a sailing-ship, a very small proportion in a steam-yacht or tug. The Cargo Ton is usually reckoned at 40 cubic feet; the space occupied by 20 centals = 4 quarters of wheat, or 25 centals of water. A steamship of 4500 tons register may be 3000 tons net; as each of these net tons will contain 2-1/2 tons of cargo of about the same weight as wheat, after allowing for cases, dunnage, &c., the ship may be described as carrying 7500 tons dead-weight. Of course, this would only apply to goods of medium weight; not to iron rails or to ore, which could only be taken as a limited part of the cargo, the rest of the space being either filled with light goods or remaining empty. The ship-owner has the choice of charging freight by measurement, usually at 40 c. ft. to the ton, or by the ton weight for metal and other heavy goods. CONCORDANCE OF CAPACITY, WEIGHT AND MEASUREMENT