Papers Connected with the Construction of the Madras Harbour

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Superintendent of Government Printing, 1885 - Harbors - 201 pages
 

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Page 180 - ... found out a weak place, it would enlarge it much more rapidly than in an inclined wall. He had seen a stone of small size show symptoms of crumbling at the beginning of winter, and in one week the little hole of single defective stone was converted into a circular breach, nearly 30 feet in diameter. An inclined wall, he had ascertained, would reflect a roller, or deep wave, nearly as well as a vertical wall, down to an inclination of 45°. This observation was of value, because at 45°, large...
Page 158 - ... reaching the shore at its base. The action is, of course, greatly intensified during storms, and particularly with the wind from the east. At such times the sea inside the harbour, though not so high as outside, is certainly of a dangerous character, being exceedingly broken. Taking these and other facts into consideration, the Committee have to record their opinion that unless means be found for closing entirely the present entrance, no radical cure will have been applied to the chief defect...
Page 33 - ... breakwaters. Large floating masses would, certainly, intercept oscillating waves of a small depth, and in moderate weather, they would often still the water. The lee side of the ' Great Eastern,' when lying at Holyhead, afforded excellent anchorage for small vessels, in light breezes. But when the great roller, the one great wave of translation came, the anchors snapped at once, showing the danger which would have been incurred, had she been moored broadside to the roller, instead of offering...
Page 180 - Now in deep water, there were not only the oscillating surface waves to be encountered, but also those which he had termed waves of translation, forming what were called rollers at the Cape of Good Hope, and when on a smaller scale, known as ground swell. These were a much more troublesome class of waves ; it was mainly with them that the Engineer had to deal, in places open to the Atlantic ; and after a storm of some duration at sea, they...
Page 180 - To reflect, or send back the roller was the most effectual plan. For this purpose, nothing more was necessary than a deep perpendicular face of perfect masonry, and so long as it stood firm, it was faultless, and the water inside was smooth as in a millpond ; for the reflection really converted the whole effect of the roller on itself, into a simple pressure of water. When such a wave was reflected on a perpendicular wall, it merely produced a hydraulic pressure, equal to that due to little more...
Page 47 - ... today to talk about some of the past and present activities of the Royal Society in relation to the developing countries. One event of historic significance was the four months' visit to India in 1944/5 by Professor AV Hill, then Biological Secretary of the Royal Society. This arose from an invitation by the Secretary of State for India, at the request of the Viceroy, to send a representative to India to advise on the organization of scientific and industrial research as part of the Indian post-war...
Page 39 - Cyclones north of the equator. When the hurricane's centre comes right on to Madras, and there takes a west course, the wind is first at N. increasing in violence for a few hours, and then a lull, or awful calm for half an hour or so, when the hurricane recommences furiously from the exactly opposite quarter, south.
Page 39 - ... and sent down top-hamper). The course to steer, and fortunately it is one which the wind assists, is SSE to SE In a few hours the vessel will probably have the wind moderate at west, and may — in fact it has been done — sail round the cyclone, the wind veering to south and then to east. Vessels at first steering east to get away from the land have run right into the vortex of the hurricane. The only danger in a southerly course is from the stormwave setting the ship on shore.
Page 158 - No matter what the direction of the wind, the unceasing swell on this portion of the coast rolls in with the crests of the waves parallel, or very nearly so, to the coast line. In no case is it believed that the angle exceeds 30° to the general line of the coast. The result is that seas enter the present mouth freely, and, owing to the small length of the harbour, are not dispersed before reaching the shore at its base. The action is, of course, greatly intensified during storms, and particularly...
Page 39 - N. increasing in violence for a few hours, and then a lull, or awful calm for half an hour or so, when the hurricane recommences furiously from the exactly opposite quarter, south. This is in accordance with the theory of cyclones. Usually the gale commences about NNW showing that the vortex of the cyclone bears about ENE Vessels, therefore, warned by the barometer, the hollow breaking surf, the threatening sky, and the signals of the...

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