358 EXPLANATION OF THE PLATES. 



PLATES XXVII. AND XXVIII. 



These plates are designed to illustrate Capt. Oliver's paper on the supposed advan- 

 tages of sail on large SEA-GOING steam vessels under various circumstances of unfavour- 

 able winds. Plate XXVII. represents a scale of different courses from the Cape of 

 Good Hope to the Isle of France, with the several distances marked, and Plate 

 XXVIII. represents four drawings of her Majesty's steam ship Phoenix, in different 

 positions with respect to the wind. 



PLATE XXIX. 



This plate exhibits the various situations of a trial at sailing of her Majesty's steam 

 ship of war Medea with the Caledonia, Vanguard, and Asia. For particulars see 

 the end of Lieut. Baldock's excellent Memoir of the Medea, Appendix, page 100. 



PLATE XXX. 



In 1816 a vessel (Caledonia) was purchased by Messrs. Boulton and Watt, and 

 fitted with two engines of fourteen horses' power, solely for the purpose of making 

 experiments under various circumstances and modifications of paddle wheels. One 

 of these experiments embraced the ascension of the Rhine in the winter of 1817 as 

 high as Coblentz. 



The plate represents a side view of the engines manufactured by Boulton and 

 Watt for the Red Rover and City of Canterbury steam vessels. This form of marine 

 engine adopted by them about this period, say 1817, was fitted on board the Fa- 

 vourite in April 1818, and, with the exception of some slight improvements principally 

 made by themselves, it still remains unchanged. 



In the first edition of this work it was stated in mistake, that they had adopted it 

 from the Clyde. This is incorrect, and we take the present opportunity of stating 

 that this mode of construction is due to Boulton and Watt, and that a preference has 

 been given to the arrangement by several of the best makers who have followed it. 



