The sea-man's practice : containing a fundamental problem in navigation experimentally verified: namely, touching the compass of the earth and ea, and the quantity of a degree in our English measures. Also an exact method or form of keeping a reckoning at sea in any kind of manner of sailing. With certain tables and other rules used in navigation. Also the plotting and surveying of places: the latitude of the principal places in England: the finding of currents at sea, and what allowance is to be given in respect of them. /