An account of some experiments upon a machine for measuring the way of a ship at sea / [John Smeaton].

  • Smeaton, John, 1724-1792.
Date:
1754
Catalogue details

Licence: Public Domain Mark

Credit: An account of some experiments upon a machine for measuring the way of a ship at sea / [John Smeaton]. Source: Wellcome Collection.

    17/24 (page 13)
    [ 3} It appears then from the preceding obfervations, that the rotation of the plate is confiderably retarded, in the quickeft motions of the fhip; and fenfibly fo, in all velocities exceeding gs miles an hour. This may proceed, firft, from the fri@tion of the machine increafing in a greater proportion than the power to turn it round. Secondly, From the water's being put in motion by the fhip, fo as to follow it in the fame direction, and that to a confiderable diftance aftern. And, Thirdly, from the plate’s jumping from wave to wave, when their concavity is great, and diftance little. | ; The firft may, in fome meafure, be helped, by ap- plying a loaded fly, of a proper fize, to the fpindle of the machine, which will prevent its fticking faft for a time, and then whirling round with great rapidity, as it is apt to do when the refiftance is great; by which means, the motion will be rendered more equal and uniform, as was juftly obferved to me by my _ Alfo, ifthe body of the machine were hung, equally: poized, upon crofs-centres, like thofe ufed for fea- compafies, or in the manner of a {wivel-gun, as cap- tain Alexander Campbell well propofed ; the {pindle of the-machine would readily place itfelf in the fame direction with the line that draws it, and. thereby avoid unneceffary frictions from. the oblique direction of the cord, ie The