Memoir Upon The Lighting Beaconage And Buoyage Of The Coasts Of France

Author : Léonce Reynaud
Publisher : Rarebooksclub.com
ISBN 13 : 9781230142258
Total Pages : 52 pages
Book Rating : 4.1/5 (422 download)

DOWNLOAD NOW!

Download or read book Memoir Upon the Light-House Illumination of the Coasts of France written by Léonce Reynaud and published by Rarebooksclub.com. This book was released on 2013-09 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1871 edition. Excerpt: ...by the line M N O P, which is represented on a scale of 0.00lwi. per nautical mile, exhibited in such a way that the errors are sufficiently small to be left out of the account. The lower catadioptric rings are not arranged in panels in the lights now under consideration; they are for fixed lights, as were produced by the parabolic mirrors of the old apparatus. The same dispositions may be adopted for the nearer eclipse lights. It will be sufficient to cause the revolving motion to increase in the inverse ratio of the duration of the intervals to be observed between the luminous apparitions; but the duration ot the flashes will be reduced in the same proportion, and it is preferred to multiply the lenses, although the intensities are thus diminished in nearly the same degree. The apparatus of the first order, whose eclipses reproduce themselves in every thirty seconds, have sixteen panels in its circumference instead of eight. When the flashes succeed each other at shorter intervals, of twenty to twenty seconds, and below that, the attempt to prolong the duration is given up for fear of reducing too greatly the power, and at the same time sutlers the fixed light to add to them, reunited in beams, the luminous rays which would have constituted it, three annular panels are superposed upon the same axis. Three principal systems are employed to produce what is called the fixed light varied by flashes, of which are the fixed lights which present white or colored flashes at regular intervals of time, more or less intense. These flashes are sometimes preceded and followed by eclipses of short duration.' The first of these systems consists in causing several lenses of vertical elements to revolve in front from a fixed-light apparatus. These...