ANON Mémoire sur les roues à augets et sur le moyenne de les perfectionner. nd. but c.1796
Large 4to. Fine ms report. (12)pp, 3 folding plates in ink and coloured wash, one with overlay. Quarter calf. Towards the end of the 18th century waterwheel design was increasingly influenced by scientific analysis and testing rather than following traditional craft-based precepts. This fine manuscript report with its ink and coloured-wash drawings is a good example of this trend.It describes a wheel invented by the (anonymous) author where the buckets were fed at the inside face from a trough running across the whole width of the wheel. The buckets, which were divided into two compartments, had hinged blades which were forced open by the mill stream at the bottom of the revolution to release the enclosed water. In this way the total weight of water maintained in the buckets was higher than in a conventional wheel. Two examples are given, one of a 24ft diameter wheel with the water entering at mid height and one of a 32ft diameter wheel with water entering at three-quarters height, comparing their performance with a conventional overshot wheel and providing simple calculations to prove the increased power and efficiency of his wheel.The manuscript is unsigned and also undated, though some of the pages are watermarked 1796. The author says that it was composed some ten years earlier, ("Ce Mémoire ayant été composé il y a environ dix ans..."), presumably in the early 1780s. It is an original document with some corrections to the wording throughout, rather than a copy of a published item.
£2200
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