ON THE PERFORMANCE OF STEAM-VESSELS. 173 



vessel of 926 knots an hour, did actually give out only 3805 lbs. That is to 

 say, the effect produced was the same as if that screw had worked in a 

 fluid whose weight was about 48 lbs. per cubic foot instead of 64 lbs. 



I am now about to exhibit some other examples from among Her Majesty's 

 ships of war. 



The questions now before us are — 



1. The resistance of the hull below the water-line in passing through the 

 water, and of the upper works, masts, rigging, &c, passing through the air, 

 the weather being calm, and the water smooth. 



2. The relation in which the thrust of the screw stands to this resistance. 



[The Admiral here gave certain results from the ' Marlborough,' the ' Re- 

 nown,' and the ' Diadem,' and proposed that a specific issue should be tried 

 by means of the ' Diadem.'] 



What would I not give, he observed, for some well-conducted experiments 

 to determine this beautiful problem of the laws which govern the action of 

 the screw in sea-water 1 It is a problem not only interesting to science, but 

 fraught with valuable results in the economical and efficient application of 

 the screw propeller. 



After commenting on the performances of the U. S. corvette ' Niagara,' the 

 Admiral observed, I have no means of forming a very definite opinion as to 

 how she will stay under low sail in a sea-way, how she will wear, how scud 

 in a following sea, or how stand up under her sails, or whether her statical 

 stability be too much or too little, or how the fore and after bodies are 

 balanced. These are points to be determined, not by the mere opinion of 

 seamen — for a sailor will vaunt the qualities of his ship even as a lover the 

 charms of his mistress — but by careful records of performances in smooth 

 water and at sea, and a comparison of such performances with calculated 

 results from drawings beforehand. Let a return of such things be annually 

 laid before the House of Commons — we shall then know whether we are get- 

 ting money's worth for our money ; and also we should receive all the benefits 

 of public criticism towards improvement. We should not then allow defects 

 to be stereotyped, till chronic blemishes are turned into beauties, or, if not 

 so, then defended as things that cannot be remedied. 



I have now completed the task which four years ago I imposed on myself. 

 Beginning with simple elementary principles, and ending with minute prac- 

 tical details, 1 have, as I conceive, shown the process by which the improve- 

 ment of steam-ships must be carried on. 



More than one hundred years ago scientific men, able mathematicians, 

 showed the physical laws on which naval architecture must rest. A succes- 

 sion of able men have shown how those laws affect various forms of floating 

 bodies. Experiments have been made with models to determine the value 

 of the resistance practically. With the exception of some experiments of 

 Mr. Scott Russell, I am not aware that any have been made with vessels ap- 

 proaching the size of ships to determine the relations of resistance to power, 

 whether wind or steam. 



Ships have been improved, and modifications of form have been arrived at 

 by a long painstaking tentative process. The rules so reached for sailing ships 

 have been superseded by steam, and we are still following the same tedious 

 process, in order to establish new rules for the application of steam power. 



I think the history of naval architecture shows that it is not an abstract 

 science, and that its progress must depend on the close observation and cor- 

 rect record of facts ; on the careful collating, and scientific comparing of such 

 facts, with a view to the induction of general laws. Now, is there anywhere 

 such observing, recording, collating, and comparing? and still more, is there 

 such inducting process ? 



