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English and American propellers for Atlantic navigation
E~g'lish and ¢~medcan Propellers,
ii1
tances from the battery. I therefore propose to make the necessary sig. nals by means of magnetic needles, which can be moved Witli the same arrangement of conductors as that already described. And although I have only used six numerals for the signals, I am very far from supposing that the working of an electro-magnetic telegraph is t:acilitated or simplified by using a small number of' original signals, or by having a small number of conductors. The simplest method of s2)elli~o,words would b e to have a needle for each letter of the alphabet, and the telegraph could be made and worked as easily by 24 needles as by a smaller number. A~d the words and sentences, which could be siunified by eombininothem in pairs, or in groups of two each, would afford great'facilities i'or the rapid transmission of ideas from one end of the line to the other. The needles could be placed in three horizontal rows, one above another: on a vertical dial plate. ]"ix. 46. r
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2
3 ,_4"
,
_16
,77
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'q[ have shown a dial plate in fig. 46, on which are placed 10 needles, with their respective figures or signs. As the needles can be deflected in only one direction, viz., with the north end towards the figure which belongs to it, there can be no mistake in understanding what sign is to he understood. I believe that" any of these telegraphs witl be found much simpler than those already before the public. They are capable of produciu~g many more signs than any other known, and may be made at a less expense." T o be Continued.
For the Journal of the Franklin Institute.
.English and Jtmericaa Propellersfor Jttlantic &"avigatlon, The success attending the C~ty of Glasgow and Nianchester,running:iS this port, and the Glc)sg'owto New York, all English ~esselsi hfisled many, myself among the number, to be very much surprised at the partial failure, at least, of the N. S. Lewis, running toBoston, ttiePioneer, to New York, and the City rf Pittsbm'gh, to this port. And it has occurred to me that the great height of our American propellers ab6ve the water, and the consequent instability caused thereby, together with their very heavy rig, will account for the whole difference; for exa.mple, thle City of .Manchesleris 274 feet long, 37~ feet beam, ahd 31 feet:holt, with an average draft of water of abou(18 feet; :while the City of Pittsburgh is 245 feet long, 38 feet beam, and 33 feet~bld,with heavy houses on deck in addition, and to this must be added about 1½feet as the diPference of thickness of the bottom between wood:~nd iron; her average.
112
.Mechanics, Physics, and Chemistry.
draft is 20 feet; it is very evident from this, that the section of the Pitlsburgh above and below water is the greatest, which, combined withher heavy rig, must, during the prevalence of the strong westerly winds of winter, give the latter a decided advantage. The English custom, looking at the points and dimensions of their propeller ships, is to make them as low as is consistent with comfort and safety, and to obtain capacity by length. Which is right? Will some one answer? X.
For the Journal of the Franklin Institute.
Ship Building in, 2Few York for 1851. The following is the number of vessels finished and remaining on the stocks in New York, at the close of the year 1851: Finished. Unfinished.
Total.
Clipper Ships, 15 3 18 Ships, . . . 7 1 8 Steamships and Propellers, 17 5 :22 Steamboats, 20 6 26 Barks and Brigs, . 3 1 4 Pilot Boats and Schooners, 21 7 28 Total, 106 vessels of all classes, whose aggregate tonnage is equal to 80,761 tons. Of the 22 vessels under the head of steamships and propellers, 17 are side wheel steamers. The total number of side wheel sea-going steamers built up to this date is 53.
Hints on the Principles which should regulate the Forms of Boats and Ships; derivedfrom o~qg'inalExperiments. ]~y MR. WILLIAM BLAb'D, of Sittingbourne, Kent.* INTrtODVCTION.
As much difference of opinion has prevailed of late years respecting the true forms of ships, I have been induced to make a series of experiments with models of wood, to ascertain, by a careful noting of results, what arc the governing laws. And I flatter myselfI have been successful, in some measure, in detecting a few of the principles which influence the speed, the stability, and the safety of vessels impelled forward by the wind, the oa5 and steam. C~Ar','EI~ I. This chapter contains the particulars of experiments undertaken to .gain a knowledge of the laws of water with regard to the head resistance it makes against bodies floating upon its surface, and impelled forward by some force~ as the wind, the oar, and steam. ~*From the London Architect, for September, 1851.
ii1
tances from the battery. I therefore propose to make the necessary sig. nals by means of magnetic needles, which can be moved Witli the same arrangement of conductors as that already described. And although I have only used six numerals for the signals, I am very far from supposing that the working of an electro-magnetic telegraph is t:acilitated or simplified by using a small number of' original signals, or by having a small number of conductors. The simplest method of s2)elli~o,words would b e to have a needle for each letter of the alphabet, and the telegraph could be made and worked as easily by 24 needles as by a smaller number. A~d the words and sentences, which could be siunified by eombininothem in pairs, or in groups of two each, would afford great'facilities i'or the rapid transmission of ideas from one end of the line to the other. The needles could be placed in three horizontal rows, one above another: on a vertical dial plate. ]"ix. 46. r
t__+_i
! 'i
2
3 ,_4"
,
_16
,77
i
.
_,71 t"+ .
t
!
'q[ have shown a dial plate in fig. 46, on which are placed 10 needles, with their respective figures or signs. As the needles can be deflected in only one direction, viz., with the north end towards the figure which belongs to it, there can be no mistake in understanding what sign is to he understood. I believe that" any of these telegraphs witl be found much simpler than those already before the public. They are capable of produciu~g many more signs than any other known, and may be made at a less expense." T o be Continued.
For the Journal of the Franklin Institute.
.English and Jtmericaa Propellersfor Jttlantic &"avigatlon, The success attending the C~ty of Glasgow and Nianchester,running:iS this port, and the Glc)sg'owto New York, all English ~esselsi hfisled many, myself among the number, to be very much surprised at the partial failure, at least, of the N. S. Lewis, running toBoston, ttiePioneer, to New York, and the City rf Pittsbm'gh, to this port. And it has occurred to me that the great height of our American propellers ab6ve the water, and the consequent instability caused thereby, together with their very heavy rig, will account for the whole difference; for exa.mple, thle City of .Manchesleris 274 feet long, 37~ feet beam, ahd 31 feet:holt, with an average draft of water of abou(18 feet; :while the City of Pittsburgh is 245 feet long, 38 feet beam, and 33 feet~bld,with heavy houses on deck in addition, and to this must be added about 1½feet as the diPference of thickness of the bottom between wood:~nd iron; her average.
112
.Mechanics, Physics, and Chemistry.
draft is 20 feet; it is very evident from this, that the section of the Pitlsburgh above and below water is the greatest, which, combined withher heavy rig, must, during the prevalence of the strong westerly winds of winter, give the latter a decided advantage. The English custom, looking at the points and dimensions of their propeller ships, is to make them as low as is consistent with comfort and safety, and to obtain capacity by length. Which is right? Will some one answer? X.
For the Journal of the Franklin Institute.
Ship Building in, 2Few York for 1851. The following is the number of vessels finished and remaining on the stocks in New York, at the close of the year 1851: Finished. Unfinished.
Total.
Clipper Ships, 15 3 18 Ships, . . . 7 1 8 Steamships and Propellers, 17 5 :22 Steamboats, 20 6 26 Barks and Brigs, . 3 1 4 Pilot Boats and Schooners, 21 7 28 Total, 106 vessels of all classes, whose aggregate tonnage is equal to 80,761 tons. Of the 22 vessels under the head of steamships and propellers, 17 are side wheel steamers. The total number of side wheel sea-going steamers built up to this date is 53.
Hints on the Principles which should regulate the Forms of Boats and Ships; derivedfrom o~qg'inalExperiments. ]~y MR. WILLIAM BLAb'D, of Sittingbourne, Kent.* INTrtODVCTION.
As much difference of opinion has prevailed of late years respecting the true forms of ships, I have been induced to make a series of experiments with models of wood, to ascertain, by a careful noting of results, what arc the governing laws. And I flatter myselfI have been successful, in some measure, in detecting a few of the principles which influence the speed, the stability, and the safety of vessels impelled forward by the wind, the oa5 and steam. C~Ar','EI~ I. This chapter contains the particulars of experiments undertaken to .gain a knowledge of the laws of water with regard to the head resistance it makes against bodies floating upon its surface, and impelled forward by some force~ as the wind, the oar, and steam. ~*From the London Architect, for September, 1851.