Editing Lock (water navigation) (section)

=== Hydro-pneumatic canal lift ===
Possibly inspired by Weldon's caisson lock, [[Sir William Congreve, 2nd Baronet|William Congreve]] in 1813 patented a "hydro-pneumatic double balance lock" in which two adjacent locks containing [[Caisson (engineering)|pneumatic caissons]] could be raised and lowered in counterbalance by the movement of compressed air from one caisson to the other. In about 1817 the [[Regents Canal|Regents Canal Company]] built one of these locks at the site of the present-day [[Camden Lock]], north London. Here the motivation was, again, water supply problems. The company insisted on various modifications to Congreve's design; the resulting installation proved to be unsatisfactory, and was soon replaced by conventional locks.<ref>{{cite web | title=Congreve's Hydro-Pneumatic Canal Lift – A Humbug! | work=London Canals | url=http://www.londoncanals.co.uk/history/cgrv.html | access-date=25 September 2013 | url-status=dead | archive-url=https://web.archive.org/web/20130927132632/http://www.londoncanals.co.uk/history/cgrv.html | archive-date=27 September 2013 }}</ref><ref>Faulkner, Alan (2005): ''The Regent's Canal: London's Hidden Waterway''. Waterways World Ltd. {{ISBN|1-870002-59-8}}.</ref>