9. Again, the engine in a factory generally runs 69 hours
per week, consequently our reckoning allows 11 hours
during the week for getting up the steam after stoppages ;
or 1| hour per day ( = 10 J hours per week) with half an
hour extra for Monday morning, making 11 hours, which is
probably an average of the hundred and odd cotton mills in
Manchester. Some persons estimate it at two hours per
day ; and if we consider that there is at least as much coal
laid on per hour in getting up the steam, as is used per hour
after, we cannot reckon less than 15 per cent, of the whole
coiisumption for that purpose; but of course it depends
almost entirely upon the quantity of water in the boiler.
Therefore we have 11*9 less by 2*1 = 9*8, or say nearly 10 lbs.
per horse, per hour, as the net consumption of coal while
the engine is at work.
10. We have been informed of some experiments lately



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Q CONSUMPTION OF FUEL.
which gave the last mentioned item of expenditure as low
as only ten per cent, although the boiler contained rather
more than the usual quantity of water, but the draught was
unusually st«rong, and from other circumstances the con-
sumption of fuel was considerably above the average. It is
difficult to come at the exact proportion used in cotton
factories, on account of the consumption for this purpose
being generally mixed up with that for steaming the mill
before mentioned, and which is generally the greatest in a
morning at the same time when the steam is being got up
for the engine, consequently very great discrepancies of
opinion are met with on this subject.
