2309 Deſcription of Mr. Logan's Spire-Buoy.[April

the mind of any pradtcal ſeamen 5 ſince his life and fortune, the merctant’s property» with the lives of thoſe under his protection, have all frequently to depend on the timely appearance of a ſingle buoy.

In the fury of a gale, when no pilot can be had, nor can the

land-marks be ſeen for dark ſurrounding clouds, it is evident that this ſignal ſhould remain permanent and apparent, to point out the channel, to corre the courſe, or to determine the future management of the ſhip. But we are ſorry to obſerve, from the confirmed teſtimony of the ableſt ſeamen in adual ſervice, that, on ſuch aw ful occaſions, the inutility and imperfe&ions of the preſent channel-búoys have(in numberleſs inſtances), been determined by the moſt fatal cataſtrophes.

It is a truth well known in the practice of navigation, that, in thoſe hours which try the utmoſt ſkill of the moſt experienced ſeamen, when fbips are flying by the impetuolity of a tempeſt through the raging billows of thé ocean, or through a high and turbulent ſea trowards the entrance of any dicult channel on the ſea-coaſt,. ſuch unfortunate events are unavoidable, where the only guide or direQion left to ſteerby,—that ofthe Channel- buoy,—becomes as uncertain as the ſoundings by the lead; for, by the variable direétion and outſet of currents, with the inde- finite progreſs_of the ſhip’s motion, no determinate courſe, un- der theſe circumſtances, Can be aſſigned by the compaſs.

An inquiry concerning, the true figure and poſition of this ſigaal of danger 15, theréfore, of real importance, in order to Extend IS AIEUIE FOES poſible effet that can be obtained from it; for, in the perfection thereof are highly intereſted the

proſperity of trade andthe ſafety of thoſe employed in navigations

Fer the uſual Form of the Buoy, ſee fig. 1» where

A. B. repreſents the ſurface of the ſea or water-line in calm

weather. C. D. The baſe of the buoy at right angles with its axis. E. F. The axis oblique to the horizon, and floáting on the ſurface, at an angle in proportion to the velocity and preflure of

the ſtream.

BGE mooring-chain, full{tretch, fixed to the ring at the vertex.

By the oblique poſition of the axis, the aQual or apparent magnitude of the buoy is loft, ſince the altitude, produced above the ſurface, bears a moſt 101 dimenſions or magnitude of the buoy itſelf; and this altitude, reſulting chiefly from che inclination of its axis to the horizon, is alſo deſtroyed by the power that gives it; that is, by the weight of the mooring-chain at the vertex.

Its being moored by the vertex renders its total immerſion more frequent(during a gale of wind,) than ¡if the mooring-chain,

by the ation of the ſtream in

ferior proportion compared with the

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