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Mode of neutralizing the local attraction of iron ships on the compass
198
Mechanie,, Phy*ica, and Chemistry.
pieces by the hand-holes did not close over the hole, and was very much shattered. Effect of, a I0 lb. charge. ]~ffeet of a 2 lb. charge.
Effect of a 1 lb. charge.
It is fbund that a ball, whatever be its veloeiiy, produces much the same effect upon the elastic lining, although not so with the iron plate, as we have shown. This wi[[ be better illustrated by the annexed sketches of the effect produced on the plate by different charges of gunpowder. Gins. Mec. Jour.
Mode of Ne~,tralizing the Local dtttraclion of Iron Ships on the Compass. Mr. C. D. Hay3, who conducted two experimental voyages between London and Cork, with the view of testing his patent method of applyiv.g the joint powers of the steam-engine and the screw as auxiliaries to sailing vessels, has made, at the same time, some observations on the effects of iron vessels on the compass, which promise to be of great service. In a pamphlet on the subject he states :-- " With a view of obtaining more correctly the error of the compasses, a person was taken on board to go as far as Gravesend, to endeavor to regulate them by the different hearings ; but from the great variety tound in every alteration of position of the ship's head, he could come to no satisfactory conchtsion; he was then kept on board to proceed further down channel. Shortly after leaving Gravesend, Mr. H a y s placed a triangle immediately over the rudder-head, on which he placed an azimuth compass, (vhich, when compared with the direciion of the river, appeared to indicate the position of the ship's head ,~orrectly, and from observations subsequently made, was found to act with lhe most perfect exactitude. "Observations were continued fi'om different beariz~gs of the lights :~nd headlands compared with the courses and distances made during ,'ira whole of the voyage to and fi'om Cork, as well as from corrections while in port, fiom the whole of which, the compass over the rudderl~ead was found ca..nelly correct, while that in the binnacle varied from one to lhree poinls. Compasses were also placed in different paris of the vessel, but in every other position than immediatel:g over the stern-post and rudder-head, a variation was shown. The common compass, as well as the azimuth, was placed over the rudder-head, nod showed the same results. " T h e height of the triangle on which the compass was placed from the head of the rudder was three feet six inches, the axis of the needle exactly plmnbing the lop of the iron post of the rudder; raising and lowering it produced no alteration.
Metals and Metallic Praperties.
199
- T h e idea of placing the compass in that position suggested itself to Mr. Hays from a conversation he had with Captain Hoskin, of the Great Britain screw iron steam-ship, on the subject of the trouble and difficulties attending the direct regulation of the compass" on board iron vessels, in which Captain Hoskin mentioned that, when they were correcting the compasses on board that ship at Bristol, it appeared to him the error diminished the nearer the compass was placed over the rudder-head and stern-post. "Inferring ti'om the above fact, that the neutralization was effected by the perpendicular attraction of the upright bars of the iron forming the nminpiece of the rudder on the needle,. Mr. Hays placed a bar of iron immediately under the compass in the binnacle, as well as under compas'ses placed in other parts of the vessel, but without producing any sensible effect; that, however, he does not think sufficient to upset the theory of the perpendicular attraction, as the bars so placed were not a fourth-part of the length of the stern-post or mainpiece of rudder; and in giving the results of the above observations he merely wishes to publish a fact which may prove valuable in adjusting the compasses on board iron vessels. The method noxv7 employed consists in counteracting the local attraction of tim vessel by the more powerful attracti6n of magimts placed about the compass, which not only are subject to variation of power by lapse of time and other causes, but may be displaced, destroyed, or lost, from numberless accidents to which vessels are subject at sea." Athenaeum.
Metals and Metallic Properties. On Saturday last, Professor Faraday continued his series of lectures on metals and metallic properties, by discussing the peculiar characteristics of iron, and, in connexion with it, those of steel. The extreme malleability of the former was clearly demonstrated, and illustrated by various beautifnl experiments; its tenacity and ductibility being also ably dilated on, as well as its affinity for the other metals. Some fine specimens of the ore were displayed, and the inherent properties of the metal in that undeveloped state ably considered. The lecturer described the process of rendering the metal at once tough and strong, being thus adapted for purposes requiring such valuable features; and stated that this property of toughness was easily removed by a violent concussion, and mentioned the fact of Mr. Nasmyth's opinion being, that the axles of railway carriages so frequently snapped asunder, though previously rendered of extreme toughness and strength, from the constant percussion occasioned by the wear and tear of 3000, or upwards, of miles of traveling. The original qualities were, however, easily reinstated by a repetition of the same process that first gave it the necessary adjuncts. The properties of steel, and its formation from the parent mineral, iron, were practically illustrated. The iron being submitted to a high heat, the carbon crept into the metal, as in the manufacture of iron it crept out, and the result was, the formation of a new and exceedingly valuable metal, possessing all the toughness and malleability of iron,
Mechanie,, Phy*ica, and Chemistry.
pieces by the hand-holes did not close over the hole, and was very much shattered. Effect of, a I0 lb. charge. ]~ffeet of a 2 lb. charge.
Effect of a 1 lb. charge.
It is fbund that a ball, whatever be its veloeiiy, produces much the same effect upon the elastic lining, although not so with the iron plate, as we have shown. This wi[[ be better illustrated by the annexed sketches of the effect produced on the plate by different charges of gunpowder. Gins. Mec. Jour.
Mode of Ne~,tralizing the Local dtttraclion of Iron Ships on the Compass. Mr. C. D. Hay3, who conducted two experimental voyages between London and Cork, with the view of testing his patent method of applyiv.g the joint powers of the steam-engine and the screw as auxiliaries to sailing vessels, has made, at the same time, some observations on the effects of iron vessels on the compass, which promise to be of great service. In a pamphlet on the subject he states :-- " With a view of obtaining more correctly the error of the compasses, a person was taken on board to go as far as Gravesend, to endeavor to regulate them by the different hearings ; but from the great variety tound in every alteration of position of the ship's head, he could come to no satisfactory conchtsion; he was then kept on board to proceed further down channel. Shortly after leaving Gravesend, Mr. H a y s placed a triangle immediately over the rudder-head, on which he placed an azimuth compass, (vhich, when compared with the direciion of the river, appeared to indicate the position of the ship's head ,~orrectly, and from observations subsequently made, was found to act with lhe most perfect exactitude. "Observations were continued fi'om different beariz~gs of the lights :~nd headlands compared with the courses and distances made during ,'ira whole of the voyage to and fi'om Cork, as well as from corrections while in port, fiom the whole of which, the compass over the rudderl~ead was found ca..nelly correct, while that in the binnacle varied from one to lhree poinls. Compasses were also placed in different paris of the vessel, but in every other position than immediatel:g over the stern-post and rudder-head, a variation was shown. The common compass, as well as the azimuth, was placed over the rudder-head, nod showed the same results. " T h e height of the triangle on which the compass was placed from the head of the rudder was three feet six inches, the axis of the needle exactly plmnbing the lop of the iron post of the rudder; raising and lowering it produced no alteration.
Metals and Metallic Praperties.
199
- T h e idea of placing the compass in that position suggested itself to Mr. Hays from a conversation he had with Captain Hoskin, of the Great Britain screw iron steam-ship, on the subject of the trouble and difficulties attending the direct regulation of the compass" on board iron vessels, in which Captain Hoskin mentioned that, when they were correcting the compasses on board that ship at Bristol, it appeared to him the error diminished the nearer the compass was placed over the rudder-head and stern-post. "Inferring ti'om the above fact, that the neutralization was effected by the perpendicular attraction of the upright bars of the iron forming the nminpiece of the rudder on the needle,. Mr. Hays placed a bar of iron immediately under the compass in the binnacle, as well as under compas'ses placed in other parts of the vessel, but without producing any sensible effect; that, however, he does not think sufficient to upset the theory of the perpendicular attraction, as the bars so placed were not a fourth-part of the length of the stern-post or mainpiece of rudder; and in giving the results of the above observations he merely wishes to publish a fact which may prove valuable in adjusting the compasses on board iron vessels. The method noxv7 employed consists in counteracting the local attraction of tim vessel by the more powerful attracti6n of magimts placed about the compass, which not only are subject to variation of power by lapse of time and other causes, but may be displaced, destroyed, or lost, from numberless accidents to which vessels are subject at sea." Athenaeum.
Metals and Metallic Properties. On Saturday last, Professor Faraday continued his series of lectures on metals and metallic properties, by discussing the peculiar characteristics of iron, and, in connexion with it, those of steel. The extreme malleability of the former was clearly demonstrated, and illustrated by various beautifnl experiments; its tenacity and ductibility being also ably dilated on, as well as its affinity for the other metals. Some fine specimens of the ore were displayed, and the inherent properties of the metal in that undeveloped state ably considered. The lecturer described the process of rendering the metal at once tough and strong, being thus adapted for purposes requiring such valuable features; and stated that this property of toughness was easily removed by a violent concussion, and mentioned the fact of Mr. Nasmyth's opinion being, that the axles of railway carriages so frequently snapped asunder, though previously rendered of extreme toughness and strength, from the constant percussion occasioned by the wear and tear of 3000, or upwards, of miles of traveling. The original qualities were, however, easily reinstated by a repetition of the same process that first gave it the necessary adjuncts. The properties of steel, and its formation from the parent mineral, iron, were practically illustrated. The iron being submitted to a high heat, the carbon crept into the metal, as in the manufacture of iron it crept out, and the result was, the formation of a new and exceedingly valuable metal, possessing all the toughness and malleability of iron,