III. ON THE MOTION OF STEAM VESSELS. 

 BY P. W. BARLOW, ESQ., CIVIL ENGINEER. 





THE benefits which this country has derived from the application of steam power to navigation 

 by its certainty and rapidity, as well as safety of communication, must be too generally felt 

 to require any remark in this place. In fact, the success which has in every instance 

 attended the employment of steam power is such, that its extent is rapidly increasing, and 

 voyages of much greater length are now about to be performed, among which may be 

 mentioned those to America and to the East Indies. 



The circumstances under which steam vessels are rendered available as a means of commu- 

 nication differ widely from each other ; some being employed in river navigation, others at 

 sea : in some, the voyages are of great length, and exposed to tempestuous and adverse 

 weather ; and in others, comparatively short and free from these disadvantages : in some, 

 speed is the principal object to be attained ; in others, great length of voyage. Under each of 

 these circumstances, vessels of a particular construction, power, and tonnage, are best adapted 

 to attain the specific object in view ; and it is very desirable to ascertain as near as possible 

 what these should be, which we think can be in a great measure accomplished by the 

 examination and comparison of the results of what has already been attained. 



Impressed with the general importance of the subject, and the advantages which may be 

 derived from such inquiries, and my former residence at Woolwich having afforded me the 

 opportunity of attending many experiments and collecting much information on the subject, 

 I beg to offer to the public the following pages on the motion of steam vessels, in the hope 

 that they may prove of utility to those interested in the progress of steam navigation. 



The power of the steam engine, when employed in propelling vessels, being applied through 

 the medium of a fluid by the reaction of the paddle wheel, there results an unavoidable loss 

 of a large portion of the power of the engine. To construct a wheel by which this loss will 

 be reduced as much as possible, is an important point to be aimed at, and many inventions 

 have appeared with the view of effecting this object. We therefore propose, in the first place, 

 to enter into a comparison of such of these wheels as have come into general use, and 

 to endeavour to illustrate the nature of their action. 



ON PADDLE WHEELS. 



The construction of the ordinary paddle wheel is so simple as scarcely to need description : 

 it consists of a circular framework of iron, supporting paddles at equal distances round 

 the rim, and radiating from the centre : these wheels are attached to a strong shaft pass- 

 ing through the vessel, to which the motion of the 'engine is conveyed by cranks placed 



