292 SECTION MECHANICS. 



bustion, and the judicious use of steel As much as 250 indicated 

 horse-power is obtained with a total weight of machinery of eleven tons, 

 including water in boilers and spare gear. The ordinary weight of a 

 sea-going marine engine of large size, with economical consumption of 

 fuel, would be four or five times as great. 



Mr. Brotherhood, with his three-cylinder air-engine worked at high 

 speed, and with a pressure of forty atmospheres, indicates, as he 

 informs me, forty-three horse-power, with a weight of engine (not 

 including air or air reservoir) of only forty-three pounds. There is in 

 this Loan Collection an illustration of the three-cylinder plan, as 

 patented by Mr. Willans, in the shape of a complete launch engine. 



I have dwelt longer upon steam machinery than I am probably 

 entitled to do, because Mr. Bramwell will go over the ground in his 

 address as prime mover. But I feel so strongly the great debt of 

 gratitude which naval architecture in England owes to her marine 

 engineers, that although I am not myself a marine engineer, I could 

 not help seeing that a discourse on English naval architecture without 

 the marine engine would be ridiculous. 



There are three or four men of modern times who have done much 

 for naval architecture, as it concerns the hulls of ships, but England 

 owes at least as much, in my judgment, to Mr. John Penn, the late Mr. 

 Joshua Field, the late Mr. John Elder, and the late Mr. Thomas Lloyd, 

 for her position in the world as to steam navigation. 



In the matter of the forms of ships I regret to say that opinions 

 differ outside the Admiralty as to whether ships intended for high speed 

 should be about as broad as they are long, or should have a length any 

 number of times, up to twelve times their breadth. 



Mr. Scott Russell's experiments, made in 1832 and subsequently, 

 have long influenced, to a considerable extent and favourably, the forms 

 of steamships, but there does not appear to be any general agreement 

 among the designers of fast ocean-going ships, as to the best pro- 

 portions and form for securing the least resistance under the average 

 conditions of an ocean voyage. Splendid results are obtained in the 

 Atlantic service ships averaging over fifteen knots an hour on the 

 whole passage. 



For the Royal Navy all our proportions and forms are subjected to 

 the investigation which Mr. Froude is able to give by his beautiful 



