Description
Excerpt from Old-Time Nautical Instruments
Based on this instrument, by laying out the circle on a table, John Davis, the explorer, devised his quadrant in 1586. At first the observer used it by facing the sun, as the cross-staff had been used, but a better form was made later where the observer had the sun at his back. This instrument has been called by sailors jackass quad rant and, supposedly from its shape, hog yoke. In early books on navi gation it is called sea quadrant. The earlier form used by the observer standing back to the sun had a solid shade vane which slid along the smaller arc of the instrument. By adjusting this a little short of the sup posed altitude oi the sun and sighting the horizon through the minute hole in the sight vane until it was seen.
About the Publisher
Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Based on this instrument, by laying out the circle on a table, John Davis, the explorer, devised his quadrant in 1586. At first the observer used it by facing the sun, as the cross-staff had been used, but a better form was made later where the observer had the sun at his back. This instrument has been called by sailors jackass quad rant and, supposedly from its shape, hog yoke. In early books on navi gation it is called sea quadrant. The earlier form used by the observer standing back to the sun had a solid shade vane which slid along the smaller arc of the instrument. By adjusting this a little short of the sup posed altitude oi the sun and sighting the horizon through the minute hole in the sight vane until it was seen.
About the Publisher
Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Details
Publisher - Forgotten Books
Author(s) - John Robinson
Hardback
Published Date -
ISBN - 9780266186045
Dimensions - 22.9 x 15.2 x 0.4 cm
Page Count - 19
Paperback
Published Date -
ISBN - 9781332172177
Dimensions -
Page Count -
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