. per sq. yd. (the same as the excise on cotton-linens) provided
they were stamped "British manufactory." The duty was varied from time
to time until its repeal in 1832.

Some more powerful force than that of man or horse was soon needed to
work the heavy water-frames. Hence Arkwright placed his second mill on a
water-course, fitting it with a water-wheel, and until the steam-engine
became economical most of the new twist mills were built on
water-courses. On rare occasions the old fire-engines seem to have been
tried.

The following passage quoted from a note in Barnes's _History_
illustrates the pressing need of the early mills: "On the river
Irwell, from the first mill near Bacup, to Prestolee, near Bolton,
there is about 900 ft. of fall available from mills, 800 of which is
occupied. On this river and its branches it is computed that there are
no less than three hundred mills. A project is in course of execution
to increase the water-power of the district, already so great and so
much concentrated, and to equalize the force of the stream by forming
eighteen reservoirs on the hills, to be filled in times of flood, and
to yield their supplies in the drought of summer. These reservoirs,
according to the plan, would cover 270 acres of ground, and contain
241,300,000 cub. ft. of water, which would give a power equal to 6600
horses. The cost is estimated at L59,000. One reservoir has been
completed, another is in course of formation, and it is probable that
the whole design will be carried into effect."[25]

As early as 1788 there were 143 water-mills in the cotton industry of
the United Kingdom, which were distributed as follows among the counties
which had more than one.[26]

Lancashire 41 Flintshire 3
Derbyshire 22 Berkshire 2
Nottinghamshire 17 Lanarkshire 4
Yorkshire 11 Renfrewshire 4
Cheshire 8 Perthshire 3
Staffordshire 7 Midlothian 2
Westmorland 5 Isle of Man 1

The need of water to drive Arkwright's machinery, and its value for
working other machinery, caused a strong decentralizing tendency to show
itself in the cotton industry at this time, but more particularly in the
twist-spinning branch. Ultimately the steam-engine (first used in the
cotton industry in 1785) drew all branches of the industry into the
towns, where the advantag