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Unsinkable vessels
Unsinkable Vessels.
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had been extended into a district similar to that which the Festiniog Railway passed through, There would have been very little chance of carrying a bill for a railway on a gauge of 4 feet 8~ inches in that district, and the result would have been, that, but for this class of railway, the present development of the mineral resources of those valleys would not have been attained ; and it was especially with reference to districts such as this, that the subject was worthy of the fullest consideration on the part of engineers. (To be continued.)
UnsbJcable Vessels. By JAs. PAI~I~ER. From the London Mechanics' Magazine, April, 1866.
As the late catastrophe has called public attention to the dangers of ocean traveling, will you allow me space to explain a plan, which, if adopted, would render every kind of vessel perfectly safe from foundering ? When any part of a vessel gives way and admits the water, the usual remedy is to pump it out as quickly as possible, either by manual power, or, in case of steamers~ by steam power, and great importance is often attached to the power of steam pumps, which, however, are often found useless in the hour of danger. Supposing a serious leak to have occurred, then follows the fight of the crew and passengers for life against the enemy. At one time the crew may gain a little, and at another the water gains a slight advantage ; and unhappily this miserable and exhausting battle is not by any means an uncommon occurrence. It seems to me that the whole system of endeavoring to keep down the water by any kind of pump is radically wrong in principle, for by pumping out the water space is left for more to come in. The true remedy is to pump air into the vessel, whereby each gallon forced in becomes a clear gain to the stability of the vessel, and leaves so much less space for water to occupy. A very little exertion in this way would soon render a vessel of 1000 tons perfectly safe from foundering, without reference to the size of the leak, which might increase sufficiently to let the engines and boilers fall through the bottom of the vessel, without in the slightest degree adding to the danger of the vessel's sinking. I therefore propose that all passenger vessels should be compelled to carry such a number of air-tight flexible bags as, when inflated in the different parts of the ship under the decks, would by their bulk prevent the vessel from sinking, even if the water had free access. The expense would not be a very large item, and nothing in comparison with the value of the sense of security to the passengers, and, therefore~ of higher passage money. An iron vessel without compartments~ laden with stone or iron, if protected in this manner, would be just as safe from sinking by having a hole knocked into her bottom as a timber laden ship. The bags, of say from twenty to fifty or more gallons~ could be kept permanently filled with air in all vacant spaces of the
894
3fechanles, _Ph!/sles, and Chemistry.
ship not required to be visited during the voyage, and, upon the up. pearance of danger, other bags could be inflated in proper positions in the cabins or elsewhere, until the bulk occupied was more than sufficient to support the ship. A bump on the rocks, leaving a large hole in the ship's bottom, provided the vessel did not break up her decks, would not then be of any great moment. In the ease of steamers the bags could be filled by air forced by the steam in a few minutes, In some experiments lately tried on the Thames in propelling a large boat with air, without machinery, I forced into the water, by aid of the steam from a one horse power boiler, about 1000 gallons of air a minute, and obtained a speed of three miles an hour through the water. If the .London had been properly fitted upon the above plan, the steam from the boiler of her donkey engine would have rendered her perfectly safe from foundering in a few minutes.
MECHANICS, PHYSICS, AND CHEMISTRY.
On the SupTosed Nature of Air prior to the Discovery of Oxygen. By GEORGEF. RODWELL, F.C.S. (Continued from vol. 1.~ page 346). From the London Chemical News, No. 316.
XIV. Rise of_Pneumatic Chemistry.--We can scarcely be surprised that the air received but little attention till a comparatively late period in the history of the world, when we remember that there existed no means of ascertaining even its most salient properties, Inquiries into the nature of an intangible and invisible body, which exercises no apparent effect upon the matter around it, belong to a somewhat advanced stage of experimental philosophy. They require the assistance of a large amount of collateral knowledge, of a refined manipulation, of a mind tutored in the mode of physical thought, and used to the classification of diverse phenomena. The most obvious property of matter is its visibility, and the conception of it divested of that property is no small effort to an ordinary mind. We all know the invariable wonderment produced at a popular lecture when carbonic acid is poured upon a lighted taper, or when hydrochloric acid gas and ammoniaeal gas are brought into contact. When we call to mind the ideas which obtain among the unscientific in the present day in regard to gaseous bodies, we cannot wonder that so little was formerly known of the air. The ancients, although they classed air among the four elements from which they conceived the world had been produced, had no de' finite idea of its nature. Many philosophers doubted whether it were material, and the great mass of the people scarcely recognised its existence. The fact adduced to prove its materiality (tile simplest and most obvious that could occur to the mind) was that it could be felt when in motion, viz : as wind. Anaxagoras went a step further, and urged as an additional proof (a) that a blown bladder resists corn-
328
had been extended into a district similar to that which the Festiniog Railway passed through, There would have been very little chance of carrying a bill for a railway on a gauge of 4 feet 8~ inches in that district, and the result would have been, that, but for this class of railway, the present development of the mineral resources of those valleys would not have been attained ; and it was especially with reference to districts such as this, that the subject was worthy of the fullest consideration on the part of engineers. (To be continued.)
UnsbJcable Vessels. By JAs. PAI~I~ER. From the London Mechanics' Magazine, April, 1866.
As the late catastrophe has called public attention to the dangers of ocean traveling, will you allow me space to explain a plan, which, if adopted, would render every kind of vessel perfectly safe from foundering ? When any part of a vessel gives way and admits the water, the usual remedy is to pump it out as quickly as possible, either by manual power, or, in case of steamers~ by steam power, and great importance is often attached to the power of steam pumps, which, however, are often found useless in the hour of danger. Supposing a serious leak to have occurred, then follows the fight of the crew and passengers for life against the enemy. At one time the crew may gain a little, and at another the water gains a slight advantage ; and unhappily this miserable and exhausting battle is not by any means an uncommon occurrence. It seems to me that the whole system of endeavoring to keep down the water by any kind of pump is radically wrong in principle, for by pumping out the water space is left for more to come in. The true remedy is to pump air into the vessel, whereby each gallon forced in becomes a clear gain to the stability of the vessel, and leaves so much less space for water to occupy. A very little exertion in this way would soon render a vessel of 1000 tons perfectly safe from foundering, without reference to the size of the leak, which might increase sufficiently to let the engines and boilers fall through the bottom of the vessel, without in the slightest degree adding to the danger of the vessel's sinking. I therefore propose that all passenger vessels should be compelled to carry such a number of air-tight flexible bags as, when inflated in the different parts of the ship under the decks, would by their bulk prevent the vessel from sinking, even if the water had free access. The expense would not be a very large item, and nothing in comparison with the value of the sense of security to the passengers, and, therefore~ of higher passage money. An iron vessel without compartments~ laden with stone or iron, if protected in this manner, would be just as safe from sinking by having a hole knocked into her bottom as a timber laden ship. The bags, of say from twenty to fifty or more gallons~ could be kept permanently filled with air in all vacant spaces of the
894
3fechanles, _Ph!/sles, and Chemistry.
ship not required to be visited during the voyage, and, upon the up. pearance of danger, other bags could be inflated in proper positions in the cabins or elsewhere, until the bulk occupied was more than sufficient to support the ship. A bump on the rocks, leaving a large hole in the ship's bottom, provided the vessel did not break up her decks, would not then be of any great moment. In the ease of steamers the bags could be filled by air forced by the steam in a few minutes, In some experiments lately tried on the Thames in propelling a large boat with air, without machinery, I forced into the water, by aid of the steam from a one horse power boiler, about 1000 gallons of air a minute, and obtained a speed of three miles an hour through the water. If the .London had been properly fitted upon the above plan, the steam from the boiler of her donkey engine would have rendered her perfectly safe from foundering in a few minutes.
MECHANICS, PHYSICS, AND CHEMISTRY.
On the SupTosed Nature of Air prior to the Discovery of Oxygen. By GEORGEF. RODWELL, F.C.S. (Continued from vol. 1.~ page 346). From the London Chemical News, No. 316.
XIV. Rise of_Pneumatic Chemistry.--We can scarcely be surprised that the air received but little attention till a comparatively late period in the history of the world, when we remember that there existed no means of ascertaining even its most salient properties, Inquiries into the nature of an intangible and invisible body, which exercises no apparent effect upon the matter around it, belong to a somewhat advanced stage of experimental philosophy. They require the assistance of a large amount of collateral knowledge, of a refined manipulation, of a mind tutored in the mode of physical thought, and used to the classification of diverse phenomena. The most obvious property of matter is its visibility, and the conception of it divested of that property is no small effort to an ordinary mind. We all know the invariable wonderment produced at a popular lecture when carbonic acid is poured upon a lighted taper, or when hydrochloric acid gas and ammoniaeal gas are brought into contact. When we call to mind the ideas which obtain among the unscientific in the present day in regard to gaseous bodies, we cannot wonder that so little was formerly known of the air. The ancients, although they classed air among the four elements from which they conceived the world had been produced, had no de' finite idea of its nature. Many philosophers doubted whether it were material, and the great mass of the people scarcely recognised its existence. The fact adduced to prove its materiality (tile simplest and most obvious that could occur to the mind) was that it could be felt when in motion, viz : as wind. Anaxagoras went a step further, and urged as an additional proof (a) that a blown bladder resists corn-