60 
Mr Robison on ilie Flexible Water-Main 
Art. VII. — Account the Flexible Water Main^ cmtrived by 
the late Mr Watt^ fcrr the Glasgow Water-Worh 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, kc. 
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 depths That part of it which lies in the bed of the 
river, is formed of pieces of 9 feet long, (exclusive of joints,) 
* 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* 
