This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1868 Excerpt: ...described, except that in this latter case some even division of the line is chosen as the initial point, instead of the zero, as in the former observation. VIII. A pair of observations for velocity having been taken, the log is still suffered to drift until the angle which its line of direction makes with some known ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1868 Excerpt: ...described, except that in this latter case some even division of the line is chosen as the initial point, instead of the zero, as in the former observation. VIII. A pair of observations for velocity having been taken, the log is still suffered to drift until the angle which its line of direction makes with some known point on land is carefully measured. IX. In selecting the fixed object to which to refer the directions of the current, the observer should give the preference to the most distant, in order that any error in the determination of his position may not so materially affect the accuracy of his observation. X. Angles of direction should always be measured with the sextant, where its use is possible; but if by reason of darkness or thick weather no fixed objects upon the shore can be seen, the observer must note the direction by compass in degrees, as N. 43 E., &c. Richie's "liquid compass" is the best now in use. XI. After using the compass for such purposes, the first opportunity should be improved for checking the error of the needle. XII. The observations would better commence at slack water, and after continuing a half day or a day, terminate with the commencement of a flood or an ebb. XIII. The velocities and directions should be noted at least every thirty minutes while the drift is strong, and more frequently as its motion fails, in order that the exact times of cessation and commencement of current may be obtained. XIV. If the current turns without absolutely slacking, the nature and progress of this turning should be ascertained by repeated observations made at least once in five minutes. In this case, the times of most rapid change of direction and the least velocity must be obtained. XV. Soundings should be made and the dept...
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Add this copy of Tides and Tidal Phenomena: for the Use More to cart. $53.62, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Hialeah, FL, UNITED STATES, published 2015 by Palala Press.
