. 



99 J ,, 



, 



15 „ 





1,022 toua. 



on trial 





giving a 







1,172 „ 



, , 



221 sq. ft 





•o7G 



20 ON THE METHOD ADOPTED TO COMPOUND 



uiulor which tlicso onji-iiics have been working, I must asl- 

 your indulgence it' I take you so far back as the year 1868 

 in which year the vessel I am speaking of was built. 

 Her dimensions are as follows : — 



Length 2G1 feet. 



Breadth ..... 

 Depth of liolil .... 

 Gross tonnage .... 

 And her " draught of water " 



was 9 feet ii inolios mean, 



diaplaeement of 

 And midship area of 

 Co-efflciont of Fineness . 



She was then fitted with a pa,ir of oscillating paddlo- wheel 

 engines oi: 350 nominal horse power, having 2 cylinders 

 each, 66 inches diameter x 72 inches stroke ; her condenser 

 was on the jot condensation principle, and the vacuum was 

 maintained at 25 inches by two single-acting air pumps, 42 

 inches diameter x 28 inches stroke. 



The feathering paddlo wheels were 23 feet 6 inches dia- 

 meter over the outer edges of the floats, and each wheel was 

 fitted with 10 floats 10 feet wide x 3 feet 8 inches deep, and 

 at the above mean draught (9 feet 3 inches) the total immer- 

 sion of the floats in both wheels was 220 square feet, giving 

 •187 square feet per ton of displacement, and just 1 square 

 foot per s(inare foot of midship area. 



Steam was supplied to these engines at 30 lbs. pressure 

 by 4 rectangular boilers having 16 fui-naoos, with a liregrate 

 area of 350 stpiare feet, and the total average consumption 

 of good Welsh coal, to which I wish to call your particular 

 attention, was 92 tons per voyage. 



I am compelled to state the consumption thus bi'oadly in 

 terms of the voyage, as, owing to disturbing causes, such as 

 "varying speeds," "strength of the tide," "waiting for water 



