64 REPORT — 1867. 



19. Area (pair of paddles ; screw disc, deductuig boss ; pair of jet-nozzles), 

 in square feet. 



20. E. Speed of vessel iu nautical miles* per hour. 



Engines. 



21. Description (single, double, treble; single-cj'lindered, double- cylin- 

 dercd; condensing, non-condensing, geared, not geared, &c.). 



22. Final volume of steam per revolution of propeller, in cubic feet. 



23. Steam cut off at (decimals of final volume). 



24. E. Revolutions of propeller per minute (paddle or sci'ew). 



25. Effective pressure of steam, lbs. 2)er inch. 



26. E. Indicated horse-power. 



EoiLEES. 



27. Total capacity, in cubic feet. 



28. Heating surface, in square feet. 



29. Eiregrate area, in square feet (including dead-plate and bars). 



30. Pressure during trial (lbs. on the square inch). 



31. E. Fuel consumed; description and weight, in lbs. per hour. 



32. Eemarks and cross references. 



In drawing up the preceding form of arrangement, the Committee have had 

 iu view not only the guidance of themselves and their calculators, but the in- 

 formation of those Avho may hereafter furnish the British Association ^ith 

 data as to the performance of steamships. 



Paddle steamers, screw steamers, and men-of-war have been separately 

 condensed and grouped. 



In condensing the Tables of the ships of war, there are vessels of which 

 many trials were reported. The mean of the majority of trials with the same 

 draught and the same propeller have been given in this Report, 



The diameter of the paddle-wheel, as given in the condensed Tables, is the 

 diameter as returned iu the printed Reports, and must not be confounded 

 with the effective diameter of the wheel. In only a few cases the effective 

 diameter has been returned, and even upon these quantities very small de- 

 pendence can be placed. For example, in Table V., Report ISGl, the diameter 

 of paddle-wheel of the ' Delta ' is 26 feet, and the effective diameter is given 

 as 22 feet ; the ' Lima ' has the same diameter of wheel, but the effective 

 diameter is given as 25-16 feet. Both are feathering wheels, and there is 

 only a difference of 1-5 feet iu the width of the float, the ' Delta having 

 a float 4-5 feet broad, and the ' Lima ' a float of 3 feet broad. 



* The length of the nautical mile is vai-ioiisly estimated. By the British Admiralty, it 

 is defined to be one minute of the equator, which, according to the latest detorniinali'ons, 

 is G08(5 feet. Another estimate is the mean length of a minute of latitude, or 0070 feet. 

 Most of the speeds in the Tables are given in Admiralty knots. 



