Before leaving England in 1806, Fulton had already made a set of drawings embodying his ideas with regard to the forthcoming _Clermont_. And so zealous was he for their safety, that before leaving by the October Falmouth packet he had these carefully placed in a tin cylinder, sealed and left in the care of a General Lyman, with instructions that it was not to be opened unless he went down during the crossing of the Atlantic. But if he reached America safely these were to be sent across to him in one of the vessels leaving about the following April, “when the risk will be inconsiderable.” The illustration on page 64 represents “Plate the First,” giving Fulton’s design of an apparatus for finding the resistance of paddles for the propulsion of the _Clermont_. In this he demonstrated the impropriety of making small paddles for a large boat. Briefly we may explain it by remarking that Fulton was proving that the paddles in the water should present, if possible, more surface than the bow of the boat, and that careful calculation must be reckoned so as to avoid wastage of power by not making due allowance for the resistance of the ship as she goes through the water. In Fulton’s time the relation of the water to the moving ship had not been accurately defined, and for that matter has not been finally settled to-day, although, thanks to the patient and valuable experiments of the late Scott Russell, W. Froude and of his son, Dr. Robert Edmund Froude, we have now considerable knowledge on the subject, which has borne practical fruit in the design of the hulls of modern ships. To-day experiments are still going on in specially-fitted tanks in different parts of England, America and Germany. At the moment of writing a special launch is being built at Marblehead, U.S.A., for purely experimental purposes under the direction of Professor Peabody, since the conditions which prevail in tanks using small models are not thought to be wholly trustworthy. The problems to be considered will embrace the number of propellers which give the best speed; they will be tried in all sorts of positions, and an endeavour will be made to ascertain the relation of the resistance of the boat to the force generated by the engines inside, and the effectiveness which the combination of hull and boat produce. Every motor-boat owner to-day knows very well that there is a good deal of difference sometimes between the calculations of the theorist in regard to the propeller and the knowledge which comes by actual use.