364 Steam Navigation to the Pacific, §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 ‘oak formation. If your coal beds are of the more recent 
formation—which i 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 oe thes managed, will no doubt 
yield you a good result. 
As ' to the spontaneous combustion, it is probably occasioned by 
th n of pyrites, (sulphuret of iron ;) which, inthe 
: t 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 ; and 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 shee 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 f 
tinning. ) ¥ 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; OF 
any other vegetable. You will, of course, reject any large 
masses of pyrites from the coal ; any masses that are visibly sprink 
ied with it, you will also throw away; the English miners call 
the pyrites mundie, With these precautions, Edo not believe. your 
coal will spontaneously ignite, and should it do so, it will, burn so 
Newly a it, canbe: het yp under till you make a. port. I should 
| ’ 1 1 nev nh on board, as 
mue iable to ferment; they may be consumed in 
ines 01 on n sor es bon i Kea a eel ae 
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