Extracts from the Report of Her Britanic Majesty's Commissioners, Appointed to Inquire Into the Condition and Management of Lights, Buoys, and Beacons; Submitted March 5, 1861, and Presented to Both Houses of Parliament by Command of Her

Extracts from the Report of Her Britanic Majesty's Commissioners, Appointed to Inquire Into the Condition and Management of Lights, Buoys, and Beacons; Submitted March 5, 1861, and Presented to Both Houses of Parliament by Command of Her

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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: ...it, that the curvature of the reflecting surfaces of the upper and lower prisms, but especially of the latter, is much too sharp. In the instance which I measured best, (second lower prism, ) the horizon image, instead of being formed on the lamp, was formed eleven inches before reaching the centre of the lamp. The effect of this was to disperse the light up and down. In the present generally erroneous adjustment of these prisms there may be advantage in this, because it throws some light on the sea; but if the prisms were generally well adjusted, much of the light which would fall with great force on the sea would be lost. See, however, the last paragraph. 3. From a remark made by Mr. L. Sauter, it is plain that the peculiar effect of re.flecti0n is not fully understood by him. He said that the adjustment of the reflecting prisms was adapted to high flame but not to a low flame. But, in reality, an addition to the height of the flame (though very valuable for the dioptric part) adds nothing to the useful effect of the reflecting part, as I have repeatedly stated, and Mr. Sauter's remarks, therefore, must be without foundation, and expressed without clear understanding of the matter. It occurs to me to suggest for Professor Faraday's consideration, whether, in a place so accessible, gas might not be used, either manufactured on the spot or led from Margate. I intend to suggest to Mr. Chance some experiments for determining the special section of the lamp flame which will send to the horizon the most brilliant light through the reflecting prism. I am, &c., Admiral W. A. B. HAMILTON, &c. G. B. AIRY. MY DEAR SIR: I enclose a tracing of a sketch that I have made of the way in which I think the questions of adjustment of the...show more

Product details

  • Paperback | 132 pages
  • 189 x 246 x 7mm | 249g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236882792
  • 9781236882790