t 37 ] 



without having it aftually put in praflice at large, 

 they know not. When I ftated to the engineers at 

 Manchefter the objeftion as to the flrength, that had 

 been hinted at Edinburgh, and explained fully the 

 manner of its conftruftion, they made very light 

 of it, and faid, upon that principle they might lift a 

 town if it fliould be required — a flrong enough hy- 

 perbole! but very expreflive of their opinion. Thefe 

 gentlemen conceive, that by adopting this contri- 

 vance in place of locks, the expence of a canal may, 

 in many fituations, be diminiflied more than one half, 

 not only by faving in the mafonry, &c. but alfo by the 

 faving of water, which will render unnecelTary large ^ 

 refervoirs, which add prodigioufly to the expence in 

 almoft every lituation, and in fome render canals to- 

 tally impradicable. None of them, however, have 

 hitherto adverted to another circumflance fufEciently, 

 which I confider as of even greater importance than 

 thefe, which is, the unlimited freedom of intercourfe 

 it will admit of, and the benefits it will procure in 

 regard to agricultural improvements efpecially, which 

 is an objeft that has fcarcely been hitherto adverted 

 to in making canals; but it would require long elu-' 

 cidations to explain this. Nothing now is wanted, 

 I think, to render canals prafticable every where, but 

 a cheap method of conflruding aqueduft bridges, 

 where they become abfolutely necelTary, about which 

 I am juft now engaged ; and though I have not my 

 drawings yet finiflied, I fliall be very foon able to 



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