THE UNITED STATES OF. AMERICA. 103 



of the difficulty which would exist in uniting an engine constructed at one place with a vessel 

 built at another, had a double provision for uniting the beams to the cranks. The former 

 were therefore made of the form of an inverted j, j giving him the choice of taking off the 

 motion either from the horizontal or the vertical branch. The latter was found most expedient, 

 and thus the working beam became, in its primitive use, a bell-crank. The connecting rod 

 was therefore extended horizontally to meet the crank. 



We may here state that this very form of engine, with the exception that the beams had the 

 usual shape, and the motion was taken off by a connecting rod directed upwards, was adopted 

 by Bell in the vessel which he constructed upon the Clyde in 1812; and that from this latter, 

 as the original model, all the engines used in the British steam boats have been derived. 



The paddle wheels of Fulton's first steam boat were attached to the axles of the cranks, and 

 the latter also bore spur wheels which drove pinions ; upon the axles of the pinions was placed 

 a heavy fly wheel. The latter was of essential use, so long as the velocity of the paddle 

 wheels themselves was not great ; but, at the speed which is now customary, they cease to be 

 of value, as the paddle wheels themselves act as regulators. Fly wheels are, in consequence, 

 no longer to be seen in American steam boats. 



The object proposed by Fulton, in the mode we have described, of connecting his water 

 wheels with the engine, was unquestionably that of enabling him to change their diameter, 

 and to raise and lower their axis of motion, until he should, by experiment, ascertain the size 

 and position most advantageous in practice. In conformity with this view of the subject, it is 

 known that the position of the axis was more than once changed ; and it is believed that the 

 diameter of the wheel was also altered, before the first steam boat was considered by him as 

 completed. In constructing his second steam boat, ' The Car of Neptune,' Fulton, being no 

 longer compelled to feel his way by experiment, made very important changes in the form of 

 his engine. The piston rod was still directed by a cross head, moving in guides, but the 

 working beams were suppressed altogether, and two cranks, adapted to two separate axles, 

 were attached directly to the cross head by connecting rods. A fly wheel was still used, 

 driven by wheels and pinions, and in the slow rate of motion to which he restricted himself, 

 was found of great value. This form of engine is still much used, with the omission, however, 

 of the fly wheel. Two views of such an engine, with a boiler of a favourite form, are given 

 in Plate cxv. 



In his first steam boat, Fulton was satisfied with endeavouring to attain the speed of four 

 miles per hour, which had been made the condition of his obtaining an exclusive right to 

 navigate the waters of the state of New York, by an Act of the Legislature of that state. By 

 alterations suggested in the experiments of the first summer, and which consisted principally 

 in raising the axle and increasing the diameter of the water wheels, the velocity of the first 

 successful steam boat was carried up to six miles per hour. 



The first voyage of Fulton upon the Hudson was performed in the summer of the year 

 1807; and in the year 1808, the same vessel, much improved in convenience, began to ply as 

 a passage boat between the cities of New York and Albany. 



In his subsequently constructed steam boats, Fulton aimed at, and succeeded in attaining, 

 a greater degree of speed ; but, even in the last which he constructed, he limited himself to 

 nine miles per hour, which, by the application of theory, derived from the best published 

 experiments, he considered as the greatest velocity which could be advantageous. 



