272 Mr. Stevenson on [Oct. 



ample conveniency for carrying 500 men with their park of 

 artillery, ammmiition, baggage, and horses, at one operation. 

 There were also cooking places on the deck of this vessel, and 

 large rooms below ; and when the troops were making forced 

 marches, a com-ier was dispatched to order preparations on 

 board of the Fly Bridge, which, on these occasions, generally 

 became one of the stages for refreshment. 



Among the many ingenious and bold designs which have been 

 formed for crossino- the rivers and ferries of Great Britain where 

 a bridge of the ordinary construction is not applicable, this 

 seems particularly to deserve the notice and attention of the 

 county gentlemen as road trustees. Here I might instance many 

 of our navigable rivers where the introduction of such a contri- 

 vance would be of the greatest importance to large districts of 

 country, where a facility in crossing extensive streams is most 

 zealously inquired after, .even at the expenditure of very large 

 sums of money, as, for example, at certain situations communi- 

 cating with the Murray Frith, the friths of Forth and Tay, the 

 rivers Tweed, Humber, Thames, Mersey, Clyde, Sec. &c. besides 

 many places in Ireland. ^ 



The Fly Bridge, or boat apparatus, which I saw at Antwerp, 

 was of very large dimensions, and extremely rude in its con- 

 struction. It will naturally be inquired by those who are inte- 

 rested in the navigation of rivers, whether this apparatus 

 materially impedes the shipping, to which it is answered that 

 much will depend upon the breadth of the river, and the num- 

 ber and dimensions of the ships frequenting it; but upon the 

 •whole, this apparatus does not present a greater obstacle to 

 shipping than the common occurrence of one vessel under sail 

 meeting with another in heating to winchcard, or lying at anchor, 

 circumstances which are unavoidable upon navigable rivers. 

 With regard to the expense of such an apparatus, calculating in 

 a general way, for a river or ferry of 500 yards in breadth, where 

 the depth of water does not exceed four or five fathoms, 

 the expense may be as follows : 



Four mooring anchors and two pieces of chain cable £ s. 



for attaching the decked boats to them 400 



A floating pier on both sides of the river 450 



Eight decked boats attached to the chain, cables, 



and mooring hawsers 800 



The price of 1200 fathoms of mooring hawser, eight 

 inches in circumference, for swinging the Fly Bridge 



both with flood and ebb tide 500 



The price of a Dahivinton Boat with a platform or 

 deck containing an area of 30 square yards, with her 



appurtenances 1000 



Contingencies on ^ taken at 15 per cent 472 10 



"3^22 10 



