152 TlMEHRI. 



under tonnage deck, which is the roomage or cubic con- 

 tent of the ship below her uppermost deck. Second, 

 there is the gross tonnage, which consists of tonnage of 

 permanent closed-in spaces on the uppermost deck 

 available for cargo, stores, &c., and crew, added to the 

 under-deck tonnage. Third, there is the register tonnage, 

 which is obtained by deducting from the gross tonnage 

 in sailing ships any space used exclusively for the accom- 

 modation of the Master, and also any space occupied by 

 seamen or apprentices, which is certified under the ton- 

 nage regulations contained in the Merchant Shipping A61 ; 

 any space used exclusively for the working of the helm, 

 the capstan, the anchor gear, and other instruments of 

 navigation, and for boatswain's stores, and the space occu- 

 pied by the donkey engine and boiler, if connefted 

 with the main pumps of the ship, and any space set 

 apart and used exclusively for the storage of sails, not to 

 exceed two and one half per cent of the tonnage of the 

 ship. With respeft to steamships there are the fore- 

 (TQing stated allowances fro.n tonnage with the exception 

 of that for sails, with the redu6lion from tonnage as 

 regards ships propelled by paddle wheels, in which the 

 engine room space is above twenty per cent and under 

 thirty of the gross tonnage of the ship, thirty-seven per 

 cent of the gross tonnage ; and in ships propelled by 

 screws, when the engine room space is above thirteen 

 per cent and under twenty per cent of the gross tonnage, 

 thirty. two per cent of the gross tonnage. In the case 

 of screw steamers, the contents of the shaft trunk is 

 ascertained by multiplying together the mean length, 

 breadth and depth of the trunk and dividing by lOo, 

 Hatchways are measured in order to ascertain the per- 



