Specimina ichnographica: or, a brief narrative of several new inventions, and experiments; particularly, The navigating of a ship in a calm, the improvement of the engine to raise water by fire, a new method of drying malt &c. For all which his Majesty has lately been most graciously pleas'd to grant his Letters Patent to John Allen, M.D / [John Allen].

  • Allen, John, 1660?-1741.
Date:
1730
Catalogue details

Licence: Public Domain Mark

Credit: Specimina ichnographica: or, a brief narrative of several new inventions, and experiments; particularly, The navigating of a ship in a calm, the improvement of the engine to raise water by fire, a new method of drying malt &c. For all which his Majesty has lately been most graciously pleas'd to grant his Letters Patent to John Allen, M.D / [John Allen]. Source: Wellcome Collection.

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    But then it is to be considered, that at lead two thirds of their Force is loft in wielding the Oars being 3 6 Foot long, which mud be moved upwards and down¬ wards, as well as backwards and forwards; and in giving it this laft Motion the Rowers are obliged to run backwards and forwards, he that is the fartheft from the Fulcrum no lefs than 6 Foot, and the reft prcportionably; add to this, that they fometimes meet with Oppofition of Water in fetching their Stroke, and fometimes quite mifs their Stroke; be- fides they wreft the Galley from Side to Side, and di- fturb its diredt Motion, one Side of the Rowers hap¬ pening almoft always to out-row, or pull ftronger than the other, which is unavoidable; this makes the Galley move in a crooked Line from Side to Side; but this you will fay is to be help’d by the Steerage, right; but then fo much as it is rectified by the Rud¬ der, fo much of the Motion is abated and retarded. There is alfo yet another Thing, which in fome meafure impedes the progreffiveMotion, which is the Dancing of: the Galley upwards and downwards, oc- cafioned by the lifting up and plunging down the Oars in the Sea. It is farther to be obfervcd, that they ftrike no more than 24 Strokes in a Minute, and one third of that Time only is applicable to give Motion to the Galley, the reft being imployed in weilding the Oars, £fc. as before noted. By Reafon of thefe Impediments it cannot be fuppofed, that more than one third of the Rower’s Strength exerts itfelf