Alexandria gazette. [volume] (Alexandria, D.C.) 1834-1974, 1859-04-14
Comparative Value of Fuels.

AT the South w ales Institute OF Engi-
neers, October meeting, very useful and
practical paper was read on the Compare
tive Value of the Fuels" The fuels are
those substances in nature which have been
produced by the combination Of carbon, OK
ygen and hydrogen, and their relative value
very much depends upon the proportions In
which the carbon and hydrogen enter INTO
their composition; whilst their entire con-
sumption depends upon the presence of oxy-
gen either as natural component or as sup
piled by the atmosphere. Of pit Goals the
varieties producing the largest amount OF
heat in the shortest space of time are most
valuable as a steam cOal-considered simply
with respect to heating properties. But the
engineer must employ other guides in select
ing coal for steam navigation or locomotive
purposes. The difference in the amount OF
stowage required for equal weights may
constitute a coal most valuable for the above
uses whilst the heating property is little
below par compared with coal Of the highest
calorific value. Goals free from sulphur,
somewha porous. or which will readily break
up on exposure to heat, and probably which
contain large amount of carbon, are re-
qured for smelling, whilst Goals OF the
highest economic value are the touchstone
of success TO railway and steam navigation
companies.
The lowest calorifc effect obtained from
wood IN given by Count Rumford, is from
the thick shavings of oak, and Is expressed
by one pound of this fuel raising 24.74S lbs.
Of water from - deg. to 2l2 deg. fahr.'
whilst the lowest of the series OF bitumlnous
Goals is from continental mine, and Is cx-
pressed by ID. of the fuel raising 43.9 lbs.
of water from 80 deg. to 2l2 deg. Fahr.-
The highest calorifc effect from wood il from
strongly dried lime tree wood, |. Id. OF which
raised 10. l3l lbs. of water, whilst the high
est effect from coal is when Aberdare Com
pany's Merthyr is the fuel, ID. raising
-. IL lbs. of water. The greatest draw back
to the use of wood as fuel is the amount Ut
water it contains.
Peat is fuel of no mean Importance IN
extent and utility. The great marsh OF
Montoire near the mouth Of the Lore Is
said to be $50 miles in circumference. In
Holland and North Germany entire districts
are covered by peat formations, from which
large quantities of fuel are annually fur
nished To various manufactures In their VI
clnlty. anu III lTtidnu VIC iuNC h'oi ~ ',''''
600 acres of peat moor, being above one
seventh of the whole island. The peat for
nations are variety of marshy plants srch
as sedges, reeds, rushes, moses, amongst
which the moss sphagmum patasfre chiefly
predominates: these have grown in stagnant
water in moist atmosphere and where
evaporation has gone on slowly. At Cap
poge, in Ireland, process has been intro
duced whereby the peat is very highly com
pressed by powerful hydraulic press. On
leaving the press it occupies about one third
of its previous volume, whilst it is found to
have lost about two tifths of its weight from
the quantity of water expelled, and it is said
to have no tendency to re-absorb water
Mallet remarks that experiments at Mur-
temburg show that cubic foot of wood is
equivalent to about =! cubic feet of dislcca-
ted turf. The great objection to this kind
of fuel is the high percentage of ash 1t con-
tains. being sometimes so abundant as to
render it quite useless: but some of the Irish
peats seem tolerably pure. Peat also varies
exceedingly in density-the heaviest varic-
ties weighing as much as 1000 lbs. per Gu
bic ward, whilst the lightesi does not exceed
500 lbs. Compared with coal. as employed
in furnaces, it is only about half as Dense
The best varieties of prepared fuel from peat
bear very favorable comparison with dried
wood, being found to contain about IL
per cent more carbon, per cent. more ny
drogen, and II per cent. less water.