108 Transactions. — Miscellaneous. 



combustion of the coal-cargoes, which followed as a matter of 

 course, as in so many other coal-ships. 



Professor Lewes has laid shippers of coal under very great 

 obligations by his highly valuable papers "On the Spon- 

 taneous Combustion of Coal-cargoes," and " On Spontaneous 

 Ignition and Explosion in Coal-bunkers," read before the 

 Institution of Naval Architects and the United Service Insti- 

 tution. In these valuable papers Professor Lewes says, 

 " Newly- won coal possesses great power to attract and 

 absorb oxygen ; that small coal, weight for weight, having 

 more surface than large, is more liable than large coal to 

 absorb oxygen and take fire ; that, as a matter of fact, fires 

 in coal-laden ships begin generally under the hatchways, 

 where the process of pulverising goes on till the cargo is com- 

 plete. Coal shipped in rainy weather incurs additional risk — 

 moisture causes crumbling and the exposure of fresh surfaces. 

 Badly-broken coal offers so many more points of atmospheric 

 contact than does a block of the same mass. Thus a cubic 

 foot has six superficial feet of surface ; but, if a cubic foot of 

 coal be subdivided into cubic inches, the amount of surface 

 exposed to oxidization would be 10,368 square inches, and 

 when pulverised into slack the power of absorbing oxygen 

 becomes very largely increased. These multiplied surfaces 

 again increase the heat proportionately. At over 100° Fahr. 

 the heat increases very rapidly : at more than 130° Fahr. 

 actual ignition is only a question of days." 



Fires in Coal-bunkeks. 



Eeferring to the ignition of coal in bunkers. Professor 

 Lewes says, " In the fast ocean-steamers it is now becoming 

 an event of frequent occurrence for the contents of coal- 

 bunkers to ignite spontaneously, and many a hand-to-hand 

 struggle has been waged between decks without the passengers 

 even suspecting the threatened danger." 



Seeing that 100° to 115° Fahr. is a common temperature 

 in stoke-holes, and up to 135° is frequently met with, and 

 that I have myself seen the temperature of a stoke-hole in 

 the tropics at 150° Fah., yet, practically nothing has been 

 done to prevent boiler and engine-room heat from passing 

 into coal-bunkers. 



Professor Lewes suggests the construction of double bulk- 

 heads, with the iron plates Gin. apart, and arrangements made 

 for the slow circulation of sea-water between them to keep 

 down the temperature in bunkers. I agree with Captain 

 Frond, E.N.E., " that structural and other difficulties stand 

 in the way of the adoption of the Professor's suggestion." 

 (See Captain Frond's admirable paper "On Heating of Ships 

 and Cargoes," read the 20th November, 1891, before the 



