340 Description of an Improvement in Jury Masts. 



means of a wheel with four notches O fixed to the pinion. 

 Fig. 3 is a side section of the machine, the lines aaaa re- 

 present boards, upon each of which is fixed the mechanism, 

 fig. 2. b b 1 1 are the hands and signal boards, one of which 

 is shown at H, fig. 2. The square boards E and F, fig. 1, 

 are fixed upon iron bars which pass through the bars or 

 radii 4 and G, .and have each of their ends made to move in 

 holes in the radius 5, and in the frame at ii, fig. 1, upon 

 which they Izvti a quarter round, by means of cross bars at 

 gg, to each end of which ropes or wires hk are fastened, 

 and which are connected with two lever?, one of which is 

 shown at P, fig. 3, the raising or depressing of which makes 

 them appear or disappear as required. 



■ ■ - i - — i' , ■ ■ i • .. • — i 



LXIIT. Description of an Improvement in Jury Masts. By 

 Capt. William Bolton, of the Royal tttivy 1 *. 



TJ Sln ' 



Jjlerewith you will receive the model of a plan for fitting 



ships' jury masts, to be formed from the. spare spars usually- 

 carried on board king's ships, and in every merchantman 

 that is properly found. By having jury masts so fitted, 

 ships will be enabled to carry as much sail as on the usual 

 regular mast ; the great use of which I need not dwell on, 

 only observing that it may be of great importance to fleets 

 after a general action, or when in want of proper lower 

 masts, either at home or abroad, and enable ships, after the 

 loss of their mast, to prosecute their voyage, or service, 

 without any deficiency of sail. 



I beg you will be pleased to lay it. before the Society, and 

 I have the honour to be, 



Sir, your obedient humble servant, 



Wm, Bolton, 



His Majesty's Ship Fisgard, 

 Shcerness', Oat. 31, 1807. 



To C. Taylor, M.D. Sec. 



* From Transactions of the Society for tlie Encouragement of Arts, Manu~ 



s Hiref, and Commerce, for 1808. The silver medal of the Society was 



voted to Capt. William Bolton for this communication, 



REMARKS, 



