Shaw's Waterworks, Sewerage. 387 



The filtration of this water is effected in 3 filters, invented 

 by Mr. Thorn, which are thus formed : — " Each filter is 

 50 ft. long, 12 ft. wide, and 8 ft. deep. The water is made to 

 percolate through them, either upwards or downwards, at 

 pleasure. When it percolates downwards, and the supply of 

 filtered water becomes sensibly less (which, after some time, 

 must happen to every filter, by the lodgement of sediment), 

 then, by shutting one sluice and opening another, the water 

 is made to pass upwards with considerable force, and, carrying 

 the sediment along with it, to fall into a waste drain made for 

 that purpose. When the lodged sediment is thus removed, 

 and the water begins to run clear, the direction of the sluices 

 is again changed, and the filter operates as before." 



Among the most ingenious arrangements connected with 

 these works are, the self-acting sluices to the different reser- 

 voirs, by which both the reception and the delivery of water are 

 regulated to the greatest nicety, with a view to the most rigid 

 economy of the fluid ; but it would be deviating too far from 

 the direct objects of our work to describe them. * What has 

 been effected by Mr, Thorn should encourage gardeners, 

 and others connected with the improvement of landed pro- 

 perty, never to think any end, which is at all desirable and 

 possible, too difficult of attainment. 



The system of drainage, or sewerage, in these towns, is as 

 bad as in most English ones. All towns situated on rivers or 

 streams drain into them, instead of into main sewers con- 

 structed parallel to their sides. This is a most important 

 point in the system of town arrangement ; and though it has 

 been utterly neglected in the case of London, and the waters 

 of the Thames have become, in consequence, unfit for use, 

 yet this ought rather to have served as a warning beacon for 

 provincial towns, than as an object of imitation. The omis- 

 sion of such sewers in Scottish towns is the more remarkable, 

 as the inhabitants are fully aware of the value of liquid 

 manure, a great quantity of which might be thus saved from 

 waste. If the evil be not checked speedily, it will be found a 

 very serious nuisance at no distant period, when, in addi- 

 tion to contaminating the air, it has polluted the only waters 

 accessible to the poor. 



To render these sewers efficient for all the purposes for 

 which they are calculated, they should be commenced farther 

 up the river, and be continued farther down its banks, than 



* We have sent the pamphlet (A brief Account of Shaiv's Water Scheme, 

 &c, Greenock, 8vo, pp. 88., 1829), in which these works are described, to the 

 editor of the Mechanic's Magazine, in whose most valuable and widely cir- 

 culated work they will probably be recorded for the benefit of engineers. 



c c 2 



