Cause of Fire in the Ship Amazon. 81 



The surface of deal in the partition opposed to the boiler, would 

 probably be better protected from fire by impregnating the wood with 

 a saline solution, which diminishes combustibility, such as the zinc 

 solution of Sir W. Burnett, rather than by coating the wood on the 

 side next the boiler with sheet iron. Indeed, this use of iron ap- 

 pears to introduce a new danger. The iron being a good conductor 

 of heat, the wood below is heated nearly as much as if uncovered, 

 and wood in contact with iron appears to be brought by repeated 

 heating to an extraordinary degree of combustibility, and to become 

 peculiarly liable to spontaneous ignition. 



Mr Braidwood, who has been led to that conclusion, gave an in- 

 stance of wood covered by sheet-iron igniting spontaneously in a 

 wadding manufactory. The numerous occasions, also, on which 

 wood and paper have been ignited by Perkins' heated water-pipes, 

 equally exemplifying the dangerous consequences which may arise 

 from moderately heated iron, in long contact with combustible 

 matter. 



The most obvious precautions for guarding against the sponta- 

 neous ignition of coal stowed in ship's bunkers, appear to be the taking 

 the coal on board in as dry a condition as possible, and the turning it 

 over, if there be room for doing so, as soon as the first symptom of 

 heating is perceived. An obnoxious vapour is described as always 

 preceding the breaking out of the fire, and affords warning of the 

 danger. The ignition of Newcastle coals in store, is not an unfre- 

 quent occurrence at the London gas-works. It appears always to 

 begin at a single spot, and is met by cutting down upon and remov- 

 ing at once the heated coals. Long iron rods are placed upright in 

 the coal heap, which can be pulled out, and indicate by their warmth 

 the exact situation of the fire. Steam can be of little avail for ex- 

 tinguishing the fire among coals in bulk ; and water, although it may 

 extinguish the fire for the time, is too apt to induce a recurrence of 

 the evil. 



For extinguishing a fire occurring in berths or cabins in the im- 

 mediate vicinity of the boiler and engine-room, steam might be more 

 advantageously applied, means of turning on the steam being pro- 

 vided upon the upper deck, or other distant place of safety. Steam, 

 however, can only be said to be efficient in extinguishing flame, or 

 a blaze from light objects, and is not to be relied upon beyond an 

 early stage of a fire. Upon a mass of red-hot cinders the extinguish- 

 ing effect of steam is insensible. 



An essential condition of applying steam with success to the ex- 

 tinction of a fire in the engine-room, would be to prevent the rapid 

 ingress and circulation of air at the same time, which is occasioned 

 by the draught of the fires. This could only be done completely by 

 valving the chimneys ; for the quantity of heated air passing off by 

 the funnels, greatly exceeds in volume the steam produced by the 

 boilers in the same time, and would rapidly convey away the steam 



VOL. LIII. NO. CV. — JULY 1852. P 



