364 Steam Navigation to the Pacific, Sj'c. 



the tertiary formation, a much more recent deposit than even the 

 newest coal ; but you may have a tertiary reposing directly upon 

 the true coal formation. If your coal beds are of the more recent 

 formation — which is very possible, (although I would not hazard 

 an opinion from seeing merely hand specimens,) then it will 

 never be as good as the true coals of an earlier geological date ; 

 'Still however, you must mine it at all events, as it is your only 

 resource, (wood being I suppose out of the question ;) it is cer- 

 tainly well worth mining, and judiciously managed, will no doubt 

 yield you a good result. 



As to the spontaneous combustion, it is probably occasioned by 

 the fermentation of iron pyrites, (sulphuret of iron ;) which, in the 

 present case is abundantly visible to the eye, and where invisible, 

 may be disseminated in minute and thin flakes and points through 

 the body of the coal. It is very prone to absorb oxygen from the 

 air and from water, and thus to heat and inflame. Your security, 

 as I conceive, will be to lay out your blocks of coal in the dry, 

 warm air, so as to have them thoroughly dry before they are 

 shipped ; qmd if it ever rains where your mines are, the coal after 

 being above ground should be housed. In the ship, the coal 

 should not be in contact with wood ; if your bunkers are not all 

 of iron, those that are of wood can be lined with stout sheet iron, 

 and the coal should be covered from the air, especially the damp 

 air of the sea, and the spray ; if protected by wooden covers they 

 should be lined with black tin, (thin sheet iron as prepared for 

 tinning.) I mention this, because it is light, and covers ought 

 not to be heavy ; but no combustible thing should lie in contact 

 with the coal — certainly not wheat or grass as you mention, or 

 any other vegetable. You will, of course, reject any large visible 

 masses of pyrites from the coal ; any masses that are visibly sprink- 

 led with it, you will also throw away ; the English miners call 

 the pyrites tnundie. With these precautions, I do not believe your 

 coal will spontaneously ignite, andshould it do so, it will burn so 

 slowly that it can be kept under till you make a port. I should 

 remark that the small coals should never be taken on board, as 

 being much more liable to ferment ; they may be consumed in 

 the engines on shore. 



