('a use of Fire in the Ship Amazon. 83 



The fire appears not to have begun in the tarred sacks lying upon 

 the boiler ; although, from their position, which was close to the 

 store-room, they must have been very early involved in the confla- 

 gration, and contributed materially to its intensity. The sacks 

 appear to have been charged each with about two pounds of tar, 

 thus furnishing together fifty pounds of that substance, in a condi- 

 tion the most favourable that can be imagined for rapid combustion. 

 The freshness of the tar, and its high temperature would make it 

 ignite by the least spark of flame, although not prone to spontaneous 

 ignition. The burning of a group of newly-tarred cottages in Dept- 

 ford, which came under the notice of Mr Braidwood, arose from their 

 being set on fire by lightning, while the sun was shining upon them, 

 and the tar liquified by the heat. 



The origin of the fire must remain, I believe, a subject of specu- 

 lation and conjecture ; but the extreme intensity, and fearfully rapid 

 spread of the combustion, are circumstances of scarcely inferior in- 

 terest, which are not involved in the same obscurity. 



The timber of the bulkheads and decks near the engine-room is 

 reported to have been of Dantzic red wood, or Riga pine, and such 

 was the character of a portion of the Amazon's timber which was 

 supplied to me for chemical examination. The wood has had its 

 temperature drawn off, and differs in that respect from pitch pine. 

 The Dantzic red wood is, in consequence, less combustible than pitch 

 pine, but more porous and spongy. Oil paint is absorbed, and dries 

 more quickly upon this porous wood than upon oak and other dense 

 woods. After the paint is well dried, pine and other woods cer- 

 tainly acquire from it some protection from the action of feeble and 

 transient flames, which might kindle the naked wood. But the 

 effect of paint — especially of fresh paint — appears to be quite the 

 reverse when the wood is exposed to a strong, although merely 

 passing, burst of flame. The paint melts, and emits an oily vapour 

 which nourishes the flame, and soon fixes it upon the wood. There 

 can be no doubt, therefore, that the timber of the Amazon was in a 

 more inflammable state than ship-timber usually is, from being 

 recently painted, and also, probably, from its newness and compara- 

 tive dryness. 



But the circumstance which appears above all others to give a 

 character to the fire in the Amazon was its occurrence, not in a 

 close hold or cabin, but in a compartment of the vessel where a 

 vigorous circulation of air is maintained by the action of the boiler- 

 fires and their chimneys. The air of the engine-room must be 

 renewed, under this influence, every few minutes, and would be so 

 although full of flames rising above deck through the hatchways ; 

 for a portion of these flames would always escape by the funnels, and 

 add to their aspirating power instead of diminishing it. The com- 

 bustion of bulkheads or decks, once commenced in this situation, 

 would therefore be fanned into activity, and powerfully supported. 



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