Identifier: transactionsofam31793amer (find matches)
Title: Transactions of the American Philosophical Society ..
Year: 1793 (1790s)
Authors: American Philosophical Society
Subjects:
Publisher: Philadelphia : The Society
Contributing Library: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library
Digitizing Sponsor: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library

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der ivay, and oc-cafioning an cafy tranfition from one degree of velocityto another : fo that her way is not checked by her beingiuddenly urged againft the refifting medium on the acccf-fion of every new force imprefTed. But the misfortune is, that this advantageous ufe of themaft can be exercifed only to a fm.all extent; for, if it iijallowed too much play, it ^n\\\ be in danger of breaking.The objedt of the prefent propofal is to enjoy the famebenefit to a greater extent and with more fecurity. The mafts, yards and rigging of a fhip receive the firftimpulfes of the wind. AH thefe are in fome degree elafticEvery twifted rope is a fpiral fpring, and every fpar capa-ble of being a little bent. But let us fuppofe that theropes were all compofed of ftraight ftrands, that the maftsand yards were inflexible, and the fails made of thin lightwood; infuchcafe, I fuppofe, that the veflel in failingby the wind would jnake but little head-way, whatever ther >■/ ■/ / ^ ft > f) r y n •
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Description of a SPRING-BLOCK. ;^;^^ the fhape of her bottom might be: but would expendthe force of the wind in heeling and Hipping to leeward.If this is true, her failing murt; be confiderably alTifted byany means that (hall encreafe the a^Stive fpring of her rin-ging. For this purpofe I have contrived what I call aSpaiNG-BLocK, to be applied to all fuch parts of the rig-ging as will admit of it with fafety and convenience, andwhere, its operation will be moft advantageous; but par-ticularly to the flieet-ropes, and, if practicable, to the deadeyes in lieu of what are called the chains. Defcription. A, fig. I, Is a block made in the ufual manner, havinga ring or eye B at one end. C, is a fpiral fpring linkedatone end to the hook D E and at the other to the ring.F, which is to be annexed by a ftaple to the timber-head,or by fome other means, to the place where it is to beapplied. The fpring C, muft be of well tempered fteel,and proportioned in ftrength to the fervice it is to per-form

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