160 APPENDIX. 



in the example of the ' Vestal,' quoted above, more than eight-ninths of the power developed 

 by the engines (exclusive of friction) appears to have been effectively employed. 



The superiority of Morgan's over the common wheel is shown in a striking manner by the 

 14th and 21st experiments in Mr. Barlow's table, page 47 of the Appendix. They were both 

 made with Her Majesty's steamer ' Firebrand,' the former with the old wheels, and a pair of 

 70 horse engines, the latter with Morgan's wheels and a pair of sixties, both light. In the 

 former case her speed was 10'15 miles, and in the latter 10'55, being improved by four-tenths 

 of a mile with one seventh less power. The common wheels had each 14 floats of 18 square 

 ft. area, and Morgan's only 9 floats of less than 13 square ft. area, which proves that the latter 

 kind of wheel does not require so much float as is given to the former, to produce an equal 

 effect. The economy of fuel arising from the use of Morgan's wheels is also proved by Mr. 

 Barlow's table, page 67, which is merely intended to show the economy of using little power 

 in proportion to the tonnage. This economy exists certainly with the same kind of wheels, 

 but if we compare Morgan's with the common wheel, we find an exception in favour of the 

 former. For example, of the ' Flamer ' and ' Hermes,' the latter ought to consume the 

 smallest quantity of coal per ton during the voyage, for two reasons : 1st, because she has 

 much less poM'er in proportion to her tonnage than the former ; and 2ndly, because, being a 

 much larger vessel, even with the same ratio of power to tonnage, she ought to consume less 

 fuel per ton by going faster ; the reverse is, however, the case, as is shown by the numbers 

 in column 11. As another example, we may compare the 'Columbia' (Morgan's wheels) 

 with the ' Messenger ' (common wheels) ; here the difference ought to be more than in the 

 foregoing example in favour of the common wheels, whereas it is still more in favour of 

 Morgan's. 



The superiority of Morgan's over Field's wheel with divided floats, as the latter has hitherto 

 been used in the Royal Navy, is demonstrated by the trials of the 'Tartarus' (see page 142, 

 and the diagrams, PI. LXXII. b, and LXXIII). 



We have now before us a pamphlet published in 1834, containing testimonials of the beauti- 

 ful action, strength, and durability of Morgan's wheels, as well as the increased safety, economy 

 and comfort, attending their use, signed by most of the officers who had at that time com- 

 manded government steamers fitted with them, as well as by Admiral Sir T. Byam Martin, 

 Vice-Admiral Sir George Cockburn, O. W. Lang, Esq. of Woolwich Dock Yard, and by 

 Charles Russell, Esq., as chairman of the Committee of the Trieste and Venice Steam Naviga- 

 tion Company. Examples of economy are afforded by the experiments on the ' Firebrand ' 

 quoted above, and by the voyages of the ' Columbia ' and ' Flamer ' (see the last mentioned 

 table, page 67). We have also received a letter from Captain Austin, who commanded Her 

 Majesty's steam frigate ' Medea ' during her late service of nearly four years. 1 He states that 



1 For the particulars of her performances during that period, see the interesting memoir of Lieut. Baldock, R.N., page 80 

 of this Appendix, particularly page 86, where her average speed from Plymouth to Malta is shown to have been 8-82 knots 

 an hour, under circumstances by no means favourable, which compare with her average speed as stated by Mr. Barlow, page 

 71, page 90, respecting her towing the squadron out of Malta harbour; compare also the speed of 9-25 to 10 knots, page 94, 

 and 9-5 knots from Ancona to Malta (against a head wind), page 95, &c. Lastly, see the end of the last paragraph but one 

 in page 98, where the author speaks of the excellence of the machinery, which must apply in a great measure to the wheels, 

 as the engines are no better than in many other steam vessels. The author of this memoir has adopted Mr. Barlow's error of 

 calling the paddles of ' Medea's ' wheels " vertically acting paddles." 



