472 EXPLANATION OF THE PLATES. 



fires. The wheels, which are of the common kind, are about 22 or 23 feet in dia- 

 meter, and the boards 9 feet wide. The cylinder is 56 inches, and the stroke 5 feet 

 6 inches. 



Plate XCV. presents a view of the vessel at sea, off Bombay ; and Plate XCVI. 

 shews the sheer draught, lines of bottom, &c. 



GENERAL OBSERVATIONS UPON THE CONSTRUCTION OF STEAMERS. 



The construction of the draught should be made with very strict attention to the 

 weight of the hull, fittings, stores, engines, coals and cargo, (if required to take goods,) 

 reducing as much as possible the component parts of the hull, and giving that form 

 which is best adapted for velocity. 



It should be particularly considered, as stated by Sir Robert Seppings, that the 

 strength of any fabric consists in the disposition of the materials, (in the connection and 

 security of its several parts,) and that " the strength of a vessel, let its construction be what 

 it may, can never exceed that of its weakest part ;" or that " union is strength," i. e. 

 giving the required strength with the least quantity of wood, copper, iron, &c. ; 

 keeping every part of the fabric as tight as is consistent with safety, equal to contend 

 with the violent action and impulse it will be subject to at sea. The fastenings 

 recommended, (and which have been so extensively introduced,) are those laid 

 down in " The New Principle of Ship Building," by Sir Robert Seppings ; a system of 

 trussing and diagonal ties of iron. (Vide the Philosophical Transactions.) 



The form should be, in midships, nearly a square with the corners rounded off, 

 or " a long, flat floor" gradually rising to an acute angle at the extremes, or fore and 

 after bodies, similar to the water lines or horizontal sections of those renowned and 

 celebrated schooners of America called " Clippers." The dead wood or extreme 

 fineness abaft being done away, as shewn in the following diagram : 



A, The water or horizontal load line. 



B, The new line of keel, the dead wood shewn by the shaded part to be done 

 away with. 



C, The old line of keel. 



