James Watt (1736-1819)

60

           Mr Robison on the Flexible Water-Main

ART. VII.—Account of the Flexible Water Main, contrived by
the late Mr Watt, for the Glasgow Water-Work Company.
By JOHN ROBISON, Esq. F. R. S. E., &c. in a Letter to Dr
BREWSTER.

MY DEAR SIR,

I HAVE now the pleasure of sending you the account which I
promised to get for you, of the Flexible Water Main, which
the late Mr Watt contrived for the Glasgow Water-Work
Company. I am indebted to Mr Creighton for the accompany-
ing drawing. I am, with much esteem, very truly, yours, &c.

JOHN ROBISON.

The Glasgow Water-Work Company derive their supply of
water from a well and tunnel formed in a stratum of sand on the
left bank of the Clyde, which affords a natural filter for the
water of the river. As the city lies on the right bank, the con-
veyance of the filtered water across the stream was a problem
of some difficulty. The fertile genius of Mr Watt, however,
enabled him to solve it*.

He suggested that a flexible iron main should be drawn across
the bed of the river, through which pumping engines on the
north side should raise the water from the well on the south
side. In executing this plan, the well and tunnel were dug in
the sand near the water's edge. The well is 10 feet in diame-
ter, and its bottom is 12 feet under the ordinary surface of the
river; the feeding tunnel is 3 feet wide and 6 feet high, and
extends for a considerable distance into the sand-bank: the well
has a wooden platform bottom ; its sides, and those of the tun-
nel are built of granite, put together without mortar, and bak-
ed with gravel, to prevent the influx of sand. The south end
of the section pipe (or main) is turned down into the well to a
sufficient depth. That part of it which lies in the bed of the
river, is formed of pieces of 9 feet long, (exclusive of joints,)
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* We have heard Mr Watt say, at the time he contrived this water-pipe, that
the idea was suggested to him from a consideration of the flexibility of the lob-
ster's tail.—ED.