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Harbors of refuge on the recoil principle
Harbors of Refuge on the Recoil Prlnclple..
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of maintaining and repairing the boiler; and that, up to the present time, the results of the experiments upon the boiler, with enlarged fire-box and shortened tubes, exhibited rather a retrograde step, than an onward progressive movement.
Harbors of l~e.f~ge on the Recoil Principle.* Mr. W. It. Smith, C. E., the inventor of a new plan for harbours of refuge and defence on the recoil principle, lately explained his principle by working models before the Liverpool Polytechnic Society. He commenced by some general observations as to the high estimation in which harbors were held by ancient nations, and described several defensive works of this description in Rome, in Greece, in Egypt, and elsewhere. The harbor of Syracuse, for instance, was ten miles in extent, and would contain 500 ships, while on the breakwaters were erected temples and ambassadors' residences. Tracing the history of harbors up to modern times, and describing the structure of the defenees--chiefly of stone, or huge masses of concrete~ he stated that no breakwater yet formed had withstood the tempest. In proof of this, he pointed to Plymouth, Cherbourg, Kingstown, and other places. Even the Bishop Rock Lighthouse, made of cast-iron pillars~ was carried away very shortly after its erection. He accounted for the Eddystone Lighthouse standing so firmly by the fact that, owing to the peculiar form of the house, the wave was carried up a beautiful parabolic curve, and its whole weight used to destroy itself; the w~ter bei~g frequently thrown right over the top of the lighthouse. The inventor ',hen dwelt upon the fearful loss of life and property which occurred annually on our coasts, in consequence of the deficiency of harbors, and also from the defects of what harbors we had. He estimated this yearly sacrifice at 1800 human lives exclusive of the fisheries, and 3,000,000/. sterling in property. He next reviewed the various modes of fbrming harbors, the time occupied in their construction, and the large and unnecessary expense attendant upon such undertakings. The de, sign of his invention was to obviate the defects of stone harbors, and to form a protection equally efficient to one-twentieth the cost if of iron, and one-fiftieth the cost if of wood. A small harbor on the recoil principle might be formed of a series of independent open frames, or gratin s of wood or iron, and be of sufficient depth and cap~city to shelter a dozen large ships, at a cost of 8000l.; whereas, m stone, ~t would revolve an outlay of about 200,000/. The principle of his invention was clearly and beautifully illustrated by the trumpet-mouthed weed of the Cape of Good Hope (laminaria buxinalis), growing to a height of from 30 to 40 feet, and which formed a natural yielding breakwater, behind which the largest class of vessels could ride securely. The framework, Mr. Smith expla.ined, is secured to the bed of the sea on screw-piles, tied across by iron tie*rods, and the breakwater is intended to be 15 feet above high-water mark. Each timber, or if iron is employed, each angle-iron, is placed the right angle ~utwards, with an intermediate space of the same width on ea¢h sid'% be* From the London Civil En.ginecr and Arch,itect's Journal', May, 1853. g
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Civil Engineering.
tween which the divided wave finds its way, and the same with the fi'amtag in the rear. The braces are of iron, with a casing of timber, and weighted with heavy iron weights; the ground mooring is lewised into the bed of the sea. The weights are sufficient to keep the sections motionless, except in a storm, when rigidity would endanger their safety; the wave then gradually gives impulse tb the section, which drifts as the weights are lifted to the extent of a few fbet, as even a solid body, like a ship or a cask, would only be driven about 10 feet to leeward by one wave. The moorings, now released, have absorbed and measured the total pressure of the wave, and spring back with their full reactive force to their original vertical position: the back fi'aming of the section, as it recoils, completely disseminates any remaining wave. Each section being separate fi'om the adjoining one, has an entirely independent play before the vermicu]ar section of the sea. Mr. Smith concluded by pointing out the economy of his invention, the freedom from silting, the facility of removal, and other advantages "which it possessed. The plan has already been laid before the Liverpool Dock Trust, the Chamber of Commerce, and many of the principal literary and scientific societies and associate bodies in diilbrent parts of the kingdom.
0~ Color Blindness in Connexion with lhe Employme~d of Colored Signals on Railways. By GEORGE WILSO,','.* In the number of your Journal for the 29th of January, 1853, Mr. V,'. I-I. Tyndall has drawn attention to the important fact, that tile red and green danger signals employed on our railways, when seen together ia certain circumstances, may be, and on actual trial were, mistaken for white--the safety signal. He also observes, that "it is not improbable that some of the accidents which have occurred in railway traveling have arisen fi'om the colors of the lights shown being indistinctly seen; perhaps from a confusion of rays frQm two or more lamps. In some cases most contradictory evidence has been given as to the color of the signal shown." Fear, probably, will dispute the justice of Mr. Tyndall's conclusion; but there is a source of danger connected with the use of colored signals, by day as xve]l as by night, not referred to by him,--probably of more importance than that "which he has indicated, and, at all events, of sutticient importance to demand notice at a period when railway accidents have been unusuall), frequent. It has long been known that certain persons cannot distinguish colors from each other; and considerable interest has been felt in this form of deWaved vision since Dalton, in whom it occurred, published the particulars of his case. Under the title of Daltonism, Chromatopseudopsis, or color blindness, the peculiarity of sight in question has been referred to by different writers. Those who are cm'ious in the matter will find the subject fiflly discussed in a 'Memoir on Daltonism, or Color Blindness,' " From the LondonAthemeumfor April. 1853.
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of maintaining and repairing the boiler; and that, up to the present time, the results of the experiments upon the boiler, with enlarged fire-box and shortened tubes, exhibited rather a retrograde step, than an onward progressive movement.
Harbors of l~e.f~ge on the Recoil Principle.* Mr. W. It. Smith, C. E., the inventor of a new plan for harbours of refuge and defence on the recoil principle, lately explained his principle by working models before the Liverpool Polytechnic Society. He commenced by some general observations as to the high estimation in which harbors were held by ancient nations, and described several defensive works of this description in Rome, in Greece, in Egypt, and elsewhere. The harbor of Syracuse, for instance, was ten miles in extent, and would contain 500 ships, while on the breakwaters were erected temples and ambassadors' residences. Tracing the history of harbors up to modern times, and describing the structure of the defenees--chiefly of stone, or huge masses of concrete~ he stated that no breakwater yet formed had withstood the tempest. In proof of this, he pointed to Plymouth, Cherbourg, Kingstown, and other places. Even the Bishop Rock Lighthouse, made of cast-iron pillars~ was carried away very shortly after its erection. He accounted for the Eddystone Lighthouse standing so firmly by the fact that, owing to the peculiar form of the house, the wave was carried up a beautiful parabolic curve, and its whole weight used to destroy itself; the w~ter bei~g frequently thrown right over the top of the lighthouse. The inventor ',hen dwelt upon the fearful loss of life and property which occurred annually on our coasts, in consequence of the deficiency of harbors, and also from the defects of what harbors we had. He estimated this yearly sacrifice at 1800 human lives exclusive of the fisheries, and 3,000,000/. sterling in property. He next reviewed the various modes of fbrming harbors, the time occupied in their construction, and the large and unnecessary expense attendant upon such undertakings. The de, sign of his invention was to obviate the defects of stone harbors, and to form a protection equally efficient to one-twentieth the cost if of iron, and one-fiftieth the cost if of wood. A small harbor on the recoil principle might be formed of a series of independent open frames, or gratin s of wood or iron, and be of sufficient depth and cap~city to shelter a dozen large ships, at a cost of 8000l.; whereas, m stone, ~t would revolve an outlay of about 200,000/. The principle of his invention was clearly and beautifully illustrated by the trumpet-mouthed weed of the Cape of Good Hope (laminaria buxinalis), growing to a height of from 30 to 40 feet, and which formed a natural yielding breakwater, behind which the largest class of vessels could ride securely. The framework, Mr. Smith expla.ined, is secured to the bed of the sea on screw-piles, tied across by iron tie*rods, and the breakwater is intended to be 15 feet above high-water mark. Each timber, or if iron is employed, each angle-iron, is placed the right angle ~utwards, with an intermediate space of the same width on ea¢h sid'% be* From the London Civil En.ginecr and Arch,itect's Journal', May, 1853. g
•
•
•
,
6
Civil Engineering.
tween which the divided wave finds its way, and the same with the fi'amtag in the rear. The braces are of iron, with a casing of timber, and weighted with heavy iron weights; the ground mooring is lewised into the bed of the sea. The weights are sufficient to keep the sections motionless, except in a storm, when rigidity would endanger their safety; the wave then gradually gives impulse tb the section, which drifts as the weights are lifted to the extent of a few fbet, as even a solid body, like a ship or a cask, would only be driven about 10 feet to leeward by one wave. The moorings, now released, have absorbed and measured the total pressure of the wave, and spring back with their full reactive force to their original vertical position: the back fi'aming of the section, as it recoils, completely disseminates any remaining wave. Each section being separate fi'om the adjoining one, has an entirely independent play before the vermicu]ar section of the sea. Mr. Smith concluded by pointing out the economy of his invention, the freedom from silting, the facility of removal, and other advantages "which it possessed. The plan has already been laid before the Liverpool Dock Trust, the Chamber of Commerce, and many of the principal literary and scientific societies and associate bodies in diilbrent parts of the kingdom.
0~ Color Blindness in Connexion with lhe Employme~d of Colored Signals on Railways. By GEORGE WILSO,','.* In the number of your Journal for the 29th of January, 1853, Mr. V,'. I-I. Tyndall has drawn attention to the important fact, that tile red and green danger signals employed on our railways, when seen together ia certain circumstances, may be, and on actual trial were, mistaken for white--the safety signal. He also observes, that "it is not improbable that some of the accidents which have occurred in railway traveling have arisen fi'om the colors of the lights shown being indistinctly seen; perhaps from a confusion of rays frQm two or more lamps. In some cases most contradictory evidence has been given as to the color of the signal shown." Fear, probably, will dispute the justice of Mr. Tyndall's conclusion; but there is a source of danger connected with the use of colored signals, by day as xve]l as by night, not referred to by him,--probably of more importance than that "which he has indicated, and, at all events, of sutticient importance to demand notice at a period when railway accidents have been unusuall), frequent. It has long been known that certain persons cannot distinguish colors from each other; and considerable interest has been felt in this form of deWaved vision since Dalton, in whom it occurred, published the particulars of his case. Under the title of Daltonism, Chromatopseudopsis, or color blindness, the peculiarity of sight in question has been referred to by different writers. Those who are cm'ious in the matter will find the subject fiflly discussed in a 'Memoir on Daltonism, or Color Blindness,' " From the LondonAthemeumfor April. 1853.