This page has been validated.
(439)
4. To remark curiously the Situation, Figures, &c. of all dangerous Rocks, Sands, Channels, Entries, and Courses of Rivers, and all difficult Passages, and Courses in all places; to measure and describe the same Exactly, their distances, bearings, &c, As also the Prospects of remarkable Coasts, Promontories, Ports, Islands, &c. in the same manner; and make Draughts, Plots, and Maps of them, with their Longitudes, Latitudes, Scales, &c. and all Beacons, Buoyes, Landmarks, Light-houses, &c. which serve for directing the Course of Ships through narrow Channels, over Bars and Banks, into Rivers, Ports, Bayes, &c. And to sound Depths near all Coasts, in all shallow Places, Roads, &c.
5. To sound the deepest Seas without a Line, by the help of an Instrument, represented by Figure 2.
To perform this, take a Globe of Firr, or Maple, or other light
wood, as A, let it be well secured by Vernish, Pitch, or otherwise,
from imbibing Water, then take a piece of Lead or stone,
D, considerably heavier than will sink the Globe: Let there be a
long
