XXXVI INTRODUCTION. 



meriting the lateral dimension of the water line ; for the easiest 

 and most advantageous way of obtaining stability is by a large 

 area of floatation, and great fulness between wind and water ; 

 or, which is the same thing, by keeping the centre of gravity of 

 the displacement at the least possible distance below the water's 

 surface, in order to obtain the maximum of stability and the 

 fastest rate of sailing : and it will not differ much from the truth 

 to assume the cross section of the vessel, as of the form of a 

 parabola. In this species of figure, the stability and capacity 

 both increase as the ordinate becomes of a higher power ; but a 

 greater breadth is necessary in proportion to the vertical height 

 of the hull to give stability. The breadth, however, should be 

 every where in the same ratio to the depth, to render the sta- 

 bility equal throughout the length, or so that the vessel will 

 undergo no strain from change of position by pitching or rolling 

 in a boisterous sea. 



The distinguishing characteristic of Chapman's works on 

 ship-building, is the application of the inductive method of 

 philosophy to the different parts of this subject, to found a 

 theory on experimental results, and where data failed, to con- 

 duct his investigations on the acknowledged principles of me- 

 chanics, and subject his conclusions to the test of observation 

 and experiment. His w r orks have never been surpassed ; and 

 in the treatise on ships of war, he collected and gave in detail 

 all the data which affected the qualities of ships, calculated 

 their effects under different circumstances, and determined on 

 theoretical principles, deduced from his experience, the dimen- 

 sions and forms of all ships of war, from a first-rate to the 

 smallest armed vessel. Their calculated elements are collected 

 in tables, and drawings of all the ships constructed agreeably 

 to these elements complete the work, which the reader will 

 find translated by MM. Morgan and Creuze, Naval Architects, 

 in the Papers on Naval Architecture, published about 1830. 



Next to Chapman's, must be ranked the Treatise of Leonard 

 Euler, on the Construction and Properties of Vessels. The 

 Calculations relative to the Equipment and Displacement of 

 Ships and Vessels of War, by John Edi/e, show by tables and 

 plates, every element and material belonging to the British 

 navy. 



