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THE

MECHANICS' MAGAZINE.

LONDON, FRIDAY, OCTOBER 7, 1859.

THE BRITISH ASSOCIATION FOR
ADVERTISING INVENTIONS.

like scientific reasoning. But these things may
be inseparable from the advertising trade.

new article-his "latest novelty." But he could have done it this year at Aberdeen; he may do it next at Oxford; and he may repeat the process year by year, until the gentlemen of Section G begin to see some glimmering of what science is, and what its advancement means.

A NAVAL LESSON BY A FRENCH
ADMIRAL.

What we are about to do is to see that, since this so-called Association for the Advancement of Science is in reality (in so far as the mechanical science section is concerned) mainly an Association for the advertisement of inventions, the fact shall be properly made kuown. And with this Ir is all very well, perhaps, to dignify humble view we call the attention of our business There are about 3,000 things with high-sounding titles, but it is readers to the fact. nevertheless desirable that their true nature inventions patented in this country every year, ADMIRAL PARIS, C.B., of the Imperial French should be known. There may be nothing very and as many more, we doubt not, conceived by Navy, Major-General Maritime of the Port of baneful in designating a motley group of men persons who do not care to patent them. We Brest, in an address on the manoeuvring of "The British Association for the Advancement honestly believe that on the average these screw ships delivered at the late Aberdeen "of Science," or in enticing the second person-inventions are equal in merit to those lately meeting of the British Association, has given age in the realm to pronounce an elaborate brought to the notice of the British Association. our naval officers a lesson which they will do eulogy upon it; but at the same time it seems Here, then, is a field for Section G! No less well to study. The work on " Naval Warfare only proper to make known the kind of pur- than six thousand papers may be read to its with Steam" which Sir Howard Douglas recently poses which the Association seems really in- scientific (!) members at the next year's Oxford published is most usefully supplemented by this tended for. We have no desire to meddle with meeting, and a like supply be repeated for their speech, in which Admiral Paris has embodied what does not much concern us, and therefore advancement" annually! As the section has many valuable facts which could only have we say nothing of the Geological, or the Zoolo- this year afforded unmistakeable signs of bar-been acquired by a naval officer in active sergical, or the Physiological, or the Ethnological, renuess, we doubt not they will pass a vote of vice. The high standing of Admiral Paris as a or any other Section of the British Association thanks to us next year for the suggestion. scientific officer in his own country, will enable which is foreign to our calling; but with the But it is not so much in the interest of the English officers to listen with satisfaction to his "Mechanical" section we think we have some- Association as in that of inventors and men of observations, while the knowledge that such thing to do, and therefore venture to make a business generally that we pen these remarks. men as he hold high rank in the French Navy remark or two upon it. We turn to you, ye tradesmen and manufac- should stimulate them to the most ardent study Now, from an article which we publish on turers, on whose eyes the "main chance" is of every new phase and ramification of their another page, it appears that at the late meeting supposed to be ever gleaming, and we ask you profession. Such men as Admiral Paris will of the Association at Aberdeen, some four-and-why are you so blind to this "splendid oppor- play a most important part in future naval wars, thirty papers (neglecting two Reports of Com- "tunity?" Why pay us for allowing you to praise and it is to be hoped they will not be withmittees) are said to have been read in this sec- your goods on our covers, and yet omnit to speak out many rivals in our own service. Those tion. About nine of these seem really not to of their merits to the Prince Consort at Aber- observations of his to which we are about to have been papers at all, in the ordinary sense deen? Be not so dull next year. Go ye, then, refer, although necessarily somewhat technical, of that term, but were either mere verbal ad- to Oxford, classic Oxford, with your able, im- are of a most interesting kind, and will doubtdresses which are not likely to obtain any per- posing papers, and under the plea of the al-less help to awaken many an officer to a better manent record, or else remarks written so vancement of science practice the science of ad- sense of the value of screw ships of war than imperfectly that probably no more will be heard vancement. Pray feel no delicacy in the mit- he has hitherto possessed. of them. This leaves, then, about five-and- ter. You have as good a right to be heard there twenty as the total number of the papers comnext year as some whom we have mentioned municated to Section G. Of these, six related had to be heard in Aberdeen this year. And exclusively to steam navigation, and, although we doubt not you will be made welcome. Only none of the six was calculated, perhaps, to do avoid being too simple and candid. Rememmuch of itself in the way of advancing science, ber it is in the name of "Science" that you it may be hoped that from all of them together speak, and therefore omit not to speak largely. -being the productions of Admiral Paris, Be sure and begin with a grave preliminary Admiral Moorsom, Mr. Oldham, Mr. Atherton, dissertation of some kind. You will not find Mr. Henderson, and Mr. Elder-some good it difficult to do this. The principle of associamay result. But if we omit these six papers tion of ideas will help you. There are plenty (all on one subject), we reduce the total number of great things in the world to tack little things to nineteen; and of these nineteen-and this is the fact to which we wish to draw especial attention-upwards of one-half are very little more than mere advertisements of new inventions-many of them patented, some of them worthless. They comprise descriptions of Mr. Avtoun's patent safety cage for miners, Mr. Robertson's patent chain-propeller, Mr. Clifford's patent boat-lowering apparatus, Mr. Wood's patent apparatus for that purpose, Mr. Clark's patent steam jet for locomotive furnaces, Mr. Allan's gas meters, Mr. Robb's reciprocat ing propellers, Mr. Rettie's lamp, Mr. Hart's railway gas apparatus, Captain Addison's coalpit balloons, Mr. Johnson's pressure gauge, some one's patent evaporating pan, and so forth.

on to.

Nor should it be forgotten that Section G of the British Association is a very aristocratical body: that is to say, there are many aristocrats who find it amusing to go to its meetings, and sit on its committees, and therefore do so. Only think, for example, of a deputation like that on steam ship performance which this section sent a few months since to the First Lord of the Admiralty, and which consisted of Messrs. M'Connell and Scott Russell, and of the Marquis of Stafford, the Earl of Caithness, M.P., Lord John Hay, Lord Clarence Paget, M.P., the Hon. A. Ellis, M.P., the Hon. Captain Egerton, R.N., and Mr. Smith! Such a group going into Whitehall to represent the science of naval architecture must, of course, have been a Now, we are not about to find fault with the capital practical joke to those noble lords and Association for encouraging inventors to do a honourable gentlemen who took part in the little business in a respectable way; by no proceeding; and as lords and gentlemen must means. We may, perhaps, think it a little have their laugh out of something or somebody strange to find ourselves invited to go all the it is pleasant to see them adopting so very inway to Aberdeen in order to hear a dozen gen-nocent a mode of getting it. But it is to the tlemen read descriptions of inventions which were published months ago, in the form of patent-specifications, and articles in scientific journals. And we may also, perhaps, think it still more strange that we should be invited to there to hear nonsensical schemes propounded with a total disregard of everything

fact of such persons being present at the Asso-
ciation's meetings that we wish to direct the
attention of our business friends. It is not
every day that a manufacturer or a tradesman
can manage to get a score or two of noblemen and
a hundred or two of gentlemen to listen to him
while he expatiates upon the merit of his last

The gallant officer commenced his observations by pointing out the fact that the propelling properties of the paddle and the screw are very different according to the form, mode of acting, and especially the position of the propellers in the ship. A few words will show these differences, and will enable us to deduce the special qualities of each propeller, and thence the method of making a good use of them for the various purposes of navigation. In what follows we shall endeavour to adhere as closely as possible to the translation of the Admiral's speech with which we have been furnished. The paddle acts, as is well known, at or near the surface of the water, and forces it in the direction of the keel when working either ahead or astern. The current produced by the resistance of the water is useless to the rudder, because it acts only on the upper part, where the rudder presents no flat surface. Moreover, the action of the paddles will not affect the ship's course, unless one is immersed more deeply than the other, thus meeting more resistance, or, as is provided for in the case of some tugs, when one acts in one direction and the other in the reverse, thus causing the ship to turn. The screw, on the other hand, acts on the water by a twisted surface, which, instead of pushing back the water in the direction of the keel, gives it a whirling motion, and projects it abaft in the shape of a cone. The screw produces a current in the same way that the paddle-wheels do, but being much below the surface of the water, and just ahead of the rudder, the latter receives the impulse of this artificial current, which acts before the vessel has moved, her inertia causing her for a few minutes to resist the impulse of the propeller. Hence, a principle is deducible, viz., that a paddle-wheel vessel cannot steer without moving, and that on the other hand a screw vessel will steer before moving, and that even long

after the propeller is at work if any obstacle | which would have been far too confined for a
resists its translating action.
paddle or sailing ship acting without the help
of hawsers.

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"topsail properly braced as by her rudder when going ahead, the only attention required being to proportionate the work of the screw to the "action of the fore-topsail, and to back slower "when the wind is light."

Another difference arises from the action of the screw, because its blades are oblique to the Again, ships are often required to remain in length of the ship, and they are pushing the one position without casting anchor; now, with stern not only ahead or astern, but also side- sails, as with paddles, there is always leeway, From these remarks it will be concluded that ways, so that if the water were equally resistant and the ship cannot stand on unless with a the screw ship is more handy than the paddle, close to the surface and below it, the equili-beam wind. There is also a difficulty in taking not only because she steers better, but also bebrium of both vertical blades would make the another ship in tow, and as large ships require cause the deviating properties of the propeller screw act equally throughout its path. But much time in sending their tow-ropes on board, are variably and usefully employed. This leads this is not the case, and the water being more they are generally obliged to drop anchor and the gallant Admiral very naturally to anticiresistant as the depth increases, the lower blade then weigh again when the second is in tow. pate that the Great Eastern will be the most moves with more difficulty than the upper one, This is a very long operation, and can easily be handy vessel afloat, if the properties of the two and the stern is acted upon sideways in propor- avoided by making use of the before-mentioned propellers are usefully employed. In reality tion to this difference in the resistances, so that properties of the screw when the wind is either she has in her paddle engines the equivalent of the ship will not move directly forward, but, if ahead or astern. "Let us suppose, firstly," says a good and constant head wind, which can be the rudder does not balance this effect, will de- the Admiral, "that a vessel is intending to take used with an admirable exactness; so that if viate always to the same side. This effect will" in tow another lying at anchor. She will she is required to turn round on herself, let the naturally be more or less energetic according "sheet and hoist her mizen topsail and top-gallant paddle turn astern and the screw ahead; the to the immersion of the screw and the length "sail according to the wind, place herself at a equilibrium of these two forces will be soon of pitch; for if the screw-shaft were at the "short distance ahead of the other, and work her obtained by giving a quicker or slower motion level of the sea and the pitch infinite, that is, "engine slowly. Thus, the backing force of the to either of the propellers. The artificial curif the blade were in the plane of the axis, the "mizen sails would be compensated by the head-rent against the surface of the rudder will be stern would only be forced round, and the ves- "ing one of the propeller, and the ship acted up- thus obtained without any motion of the ship, sel not propelled. Consequently, in the actual on by these two equal and opposite forces will and she will turn herself very easily. The mostate of things, the action of the screw on "remain motionless; but she will steer as well tion will be accelerated at pleasure by working the stern is compounded of the propelling and as if making way by means of the artificial the propellers with more or less energy, but of the lateral effect. This cannot be avoided, "current before spoken of, and she will change always equally, which is easily obtained by and can only be lessened by an increase of her position or remain exactly motionless, and looking at some point on shore, or the water immersion, or by a reduction of the pitch. A "without any deviation of her head, as long as alongside, and adjusting the throttle valves right-handed thread deviates the ship to larboard may be required. I have done this several properly. But that is not all; she will steer when going ahead and to starboard when going "times when ordered to take ships in tow, and even when making way astern, which would be astern it is the reverse for a left-handed "remained once more than twenty minutes with impossible in any other vessel, unless with a "scarcely any change of position or direction." good breeze acting on the topsail; for, suppose This combination of the propelling powers of the power of the screw to be overcome by that both sails and the screw may also be employed of the paddles, the ship will go astern, but still in maintaining the ships with an oblique direc- preserve the artificial current necessary to steer, tion of the wind, two or three points, for exam- and it will be a matter for experiment to find ple, by bracing properly the mizen topsail; but out the proportion of the maximum of back then there is a slight leeway, and if the wind speed at which the ship will steer, that is to blows in the direction of the beam it is the say, the minimum of screw power to be emusual condition of sailing or paddle-vessels ployed in proportion to the paddle. This being standing on. known by experiment, the Great Eastern could go up the Thames to her moorings stern first, and steering as steadily as if she were head first; should the latter be preferred, the pro. perties of the united propellers will still be useful; thus, if it is wished to keep her steering short without making much way, the paddles should be backed sufficiently to balance the screw, and keep the ship at two or three knots, or less, if wanted, whilst the screw is turning so as to give a speed of ten or twelve knots, and so that the helm will have an energy unknown on board any other ship, and will not be subject to the influence of tides or currents. The Great Eastern would therefore go to her moorings either head first or stern first with greater facility and security than many ships of common dimensions but moved by a single propeller.

screw.

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The screw,

From these considerations, says Admiral Paris, "it would appear at first sight that the "paddle acts much better in making a ship "steer well than the screw, and that the dis"turbances caused by the screw on the ship's way presents obstacles to the management of "the ship; but it is not so, and these proper"ties of the screw may be used in such a way as to manoeuvre in various ways impossible "with paddles." If, for instance, it is desired to turn a vessel short round at the moment before raising anchor, a paddle-vessel will want ropes, or at least sails if the wind permits, and her propeller will be used only to resist the wind, or to act in the direction of the keel. however, enables her to turn round on the same place even in a calm, for if she moves gently ahead with the anchor still holding on, the screw, by thrashing on the rudder, makes it steer the ship as though she were under way. This is well known, many vessels adopting this plan in order to acquire the right direction without moving ahead, and the moment that this is attained weighing anchor and going ahead. If she is not at anchor, a screw-vessel may be made to turn on herself, by the help of her own inertia. Thus, let the screw work back and the ship will begin to turn her head to starboard, and when she has gone half her length reverse the engine at an increased speed with the helm aport. The ship" will then move ahead, still turning to the same side; and by repeating the same operation several times the turn of the whole horizon will be made in a much shorter time than would at first be supposed, and the space required to turn in will be dependent on the duration of each operation. If there is any wind the sails may be used to accelerate the evolution, either by their oblique action on the ship by the aid of the jib or mizen sail, or by increasing the speed of the screw and backing the sails. These manœuvres of screw-ships, which are manifestly of the highest importance especially for war ships, which may require to change position in action-have often been performed, says Admiral Paris, and have enabled such ships to thread their way amongst crowded shipping in a space

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Further, it is very often useful to be able to back a vessel in any direction, and when he can do this a captain will dare to go anywhere. With a paddle-vessel this is possible for short distances, combined with the help of some sails; but with the screw alone it is impossible, owing to the side action above named: so in a calm a screw-ship cannot follow by her stern the same way she made by her head; she must have room enough to turn on herself. Again, suppose a vessel is required to remain in the same place, with the wind astern. She hoists her fore-topsails, and works her screw back; these two forces can be balanced by the throttle valve, and their propelling action brought into equilibrium. But the screw deviates the vessel to starboard, and this can be avoided by hauling on the larboard braces of the fore-topsail, so that not only the pushing actions but also the Being a seaman, my thoughts were natudeviating ones are entirely balanced. "I have rally directed," said Admiral Paris in conclusion, "remained at rest by these means several "to the method of making good use of the times," says Admiral Paris, "and once for an "means put into the hands of a captain by the experiment for half an hour; it was on board "skill of the engineers who invented and inade "a frigate, 76 metres, or 226 feet long; she "the various engines. So, from one trial to changed her direction only one point and a "another, and reflecting on the principle of the "half of the compass, and varied in her position "action of the screw, I arrived at a new theory "only the distance between two ports; with "on the manœuvres of these kinds of ships; and "more attention she would have been exactly "to illustrate the difference of their manage"motionless." If it is wished to make stern "ment from that of paddle vessels, I have arway, it is very easy to work the ship to accom- 'ranged in two columns in my catechism for plish this, by ordering the screw to work seamen and steam engineers the answers to quicker, at the same time bracing the fore-top-"questions on this subject, which greatly facili sail somewhat more; thus the latter will not "tates the comparison; the left column for push too much ahead, and will balance better "paddles and the right for the screw. A chapthe deviating action of the screw. "By this ter of 100 octavo pages has been devoted to "method," he says, "on board the same frigate "the elaborating the details of these practical "I went astern at a speed of three knots, and "with a deviation of one point in half an hour. "The ship was steered as exactly by her fore

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means of managing screw ships as easily as a "horse, and to expose in a clear manner the "variety of methods employed with each pro

"peller to make any manoeuvre requisite in "intricate navigation, and especially on leaving "or entering crowded harbours. I should have "been glad to see these methods experimented "on, or have used them myself if permitted, on "board the Great Eastern, as this ship is the "most interesting problem of modern naviga"tion, and one which involves not only the "speed, distance, and economy of transport, "but also the means of manoeuvring with faci"lity and security this tremendous body, the "largest ever created by man to be moved on "the seas."

HEARDER'S SUBMARINE TELEGRAPH CABLE.

THIS novel and interesting application of scientific research to the removal of a difficulty that threatened to circumscribe the limits of success in submarine telegraph cables, and which has excited of late considerable interest in the minds of telegraph engineers, was last week submitted by the inventor for the approval of the judges of the Royal Cornwall Polytechnic Institution, at their annual exhibition held at Falmouth. Their entire satisfaction with the efficacy of the plan, and their perfect concurrence in the soundness of Mr. Hearder's scientific reasonings, were manifested by the unanimous award of the Society's first class silver medal. Of the many modifications of which Mr. Hearder's plan for obviating the effects of induction is susceptible, he appears to have selected the following:The wire strand, which is five or six times as large as that of the Atlantic cable, is first coated with a number of strands of a very superior flax twine, incorporated with an adhesive insulating medium, which binds them firmly together. They are laid on in a very long spiral direction, the reverse of the twist of the wire; this is secondly coated with a layer of guttapercha, and, thirdly, with another layer of twine laid on in the same manner, but in a direction opposite to that of the first. The whole is subsequently covered with two layers of guttapercha. In other samples the first layer of twine next the wire is omitted, and one or two layers of twine and adhesive composition are laid on after the first coating of gutta-percha, and are subsequently covered with two thicknesses of gutta-percha.

Mr. Hearder's patent mainly consists in the employment of fibrous materials between the wire and the insulating medium itself. The advantages of it are stated by Mr. Hearder to be -1st. The reduction of the disturbing influences of inductive action to a minimum upon wellrecognised electrical principles, which have been submitted to the test of experiment. 2nd. Improved insulation: the heavy hydraulic pressure to which the submerged cable would be subject, not only prevents the possibility of fissures occurring in the adhesive insulating composition, but any fissures in the gutta-percha itself would be effectually filled or closed over by this composition, thereby rendering the chance of leakage from damage, resulting from rough usage to the cable, infinitely less than with gutta-percha alone. 3rd. Increased strength every strand of twine possesses a breaking strain of about 40 lbs., consequently, as the samples contain from 25 to 50 of these strands it is evident a breaking strain of from 1,000 to 2,000 lbs. is added to that already possessed by the cable itself without the twine. 4th. Extreme lightness: the specific gravity is from 13 to 14, varying with the size of the conducting wire. 5th. Perfect facility of recoVery after submersion: as the cable will support a weight five times greater than that of any portion of its length which can be submerged in depths available for telegraphic pur

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1. Report of the Committee on Steam Ship Performance. [We have been favoured with copy of this report, and if we can extract any thing useful from it for our readers, will not fail to do so.]

2. Admiral Moorsom.-On the Performance of

Steam Vessels. [A copy of this paper has not yet reached us; we may state, however, that it consisted mainly of statistics.]

3. J. Oldham, C.E.-Report of the Progress of Steam Navigation at Hull. [This paper is pub. lished in our present number.]

4. Charles Atherton, communicated by H. Wright. On Mercantile Steam Transport Economy, as affected by the Consumption of Fuel. [We have been favoured with a copy of this paper, and shall either publish or notice it in an early number.]

5. J. Macquorne Rankine, LL.D.-A Condensed Abstract of Experiments, by Messrs. R. Napier and Sons, on the Strength of Wrought Iron and Steel. [This paper will be published in

an early number.]

6. Donald Bain, communicated by H. Wright. been a speech rather than a paper; at any rate we -On Harbours of Refuge. [This seems to have can at present get no report of it.]

FRIDAY, Sept. 16.

1. P. Le Neve Foster.-Report of the Patent Committee. [Published in MAGAZINE for last week (Sept. 30.)] the MECHANICS'

2. William Fairbairn, F.R.S.-On Experiments to determine the Efficiency of Continuous and Self-acting Breaks for Railway Trains. [This paper is published in our present number.]

3. J. F. Bateman, C.E., F.R.G.S.-Description of Glasgow Water Works. [This was a verbal description of drawings, of which no report has reached us.]

4. R. Aytoun.-On a Safety Cage for Miners. [This was, we believe, a description of an invention recently patented by the author, the specification of which has been published in due course by the Commissioners of Patents.]

SATURDAY, Sept. 17.

1. J. F. Bateman.-On the Result of Boring for Water in the New Red Sandstone near Shiff

all, in the County of Salop. [This is published in our present number.]

2. W. Robertson, communicated by Peter

Spence.-On a Patent Chain Propeller. [We have a copy of this, and will publish it if we find it of sufficient interest.]

3. Admiral Paris, C.B.-On the Manoeuvring of Screw Vessels. [This is abstracted in a leading article of our present number.]

4. Arthur Taylor, communicated by H. Wright. -On the True Action of what are called Heat Diffusers. [This will be published in an early number.]

5. A. Batten.-On a Boat Lowering Apparatus. This was a paper on Mr. Clifford's apparatus; we hope to find space for it hereafter.]

6. E. A. Wood.-On a Mode of Suspending, Disconnecting, and Hoisting Boats attached to Sailing Ships and Steamers at Sea. [This paper was not, we believe, read. We may state, however, that it consisted mainly of a description of the apparatus described and illustrated at page 105 of the MECHANICS' MAGAZINE for the 12th of August last.]

7. D K. Clark, C.E., communicated by H. Wright.-On Smokeless Coal-burning Locomotive Engines. [This is published in our present number.] MONDAY, Sept. 19.

1. Abbé Moigno.-On a New Gas-burner. 2. Abbé Moigno.-On an Automatic Injection for Feeding Boilers, by Mr. Giffard.

3. Abbé Moigno.-On a Heliço-meter, an Instrument for Measuring the Thrust of the Screw Propeller.

4. Abbé Moigno.-On an Application of the Moving Power arising from Tides to Manufacturing, Agricultural, and other Purposes; and especially obviate the Thames nuisance.

[The above four papers were written in too imperfect English to find a place in our pgaes.] 5. Alexander Gibb.-Description of the Granite Quarries of Kincardineshire. [We have a copy of the paper, which we may perhaps publish in an early number.]

Alexander Allan.-On Gas Meters.

6. {Alexander Allan. Description of an Improved Method of Obtaining a True Liquid Level. We have a copy of this paper, but not (at present) of the drawings which illustrated it.] Propellers. [This paper, however fit for the 7. John Robb.-On the Comparative Value of British Association it may have been, has no sort of claim to be published in our columns. The invention advocated in it is a very old one, and the views of the author are not such as to help it at all.]

8. Alexander Gerard.-An Experimental Illustration of the Gyroscope. [This does not admit of publication.] TUESDAY, Sept. 20.

1. William Fairbairn. Experimental Researches to Determine the Density of Steam at Various Temperatures. [An abstract of this paper will be published in an early number.]

2. J. Elder.-On the Steam Machinery of the Callao, Bogota, and Lima. [We have a copy of this, which we may publish in an early number.] 3. J. P. Joule, LL.D., F.R S.-On Surface Condensation. [This was little more than a memorandum; no copy of it has yet reached us.] 4. Mr. Rettie.-On a Submarine Lamp. [An abstract of this will be published in an early number.]

5. G. Johnstone Stoney.-On the advantages of the 40-inch Metre as a Measure of Length. [This is published in our present number.]

6. Andrew Henderson.

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On India River Steamers and Tow-boats--giving an account of their improved construction for light draft, capability for cargo, and fittings, conducive to manageability in shallow rapid rivers, &c., and of the practical value of the Dynamometer in showing the resistance of vessels in tow, at different speeds and loads, with the result of testtrials made in England. [We have not yet received a report of this paper, but have been informed that it is in the main a résumé of what

Mr. Henderson has before read and published on the same subject.]

7. G. Hart--On Gas Carriages for Lighting Railway Carriages with Coal instead of Oil. [This paper describes a method by which coalgas may be applied to railway carriages. The author does not seem to be aware of what has been before proposed and done in this respect. We will, however, publish it if we find it will be of any value to our readers.]

8. Captain J. Addison.-On Coal-pit Accidents. [This paper recommends the carrying out of an idea which occurred to the gallant author on seeing a man vending children's balloons in the Rue de Rivoli, Paris, viz., that of employing similar balloons to test the atmosphere of mines, the presence of carburetted hydrogen being detected by the balloons not rising to the top of the mine, chamber, or passage, and the presence of carbonic acid by their not sinking to the bottom.] 9. H. Johnson. - On a Deep-sea Pressure Gauge. [We have a copy of this paper, and shall publish it in an early number.]

10. Mr. Davies, F.R.S.A., F.L.S.-On a Patent

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There were a few papers which will be of interest to our readers read in other sections of the Association; these we shall publish in due time.

Disc Pan for Evaporating Saccharine Solutions | pair of carriages, so that they may be undisturbed
and other Liquids at a Low Temperature. [We by the rocking motion of the train or the action
shall probably publish this in an early number.] of the buffers.
11. Adam Topp.-Various Modes of Fire Es-breaks may be worked by a single person at either
In this way the whole of the
capes, Boats, &c. [This miscellaneous affair has end of the train communicating his power to each
not reached us in any form.]
break though the agency of the continuous shaft.
stance by Mr. Newall and subsequently by Mr.
Again, there have been applied, in the first in-
Fay, powerful springs beneath each carriage, con-
nected with the arms of the rocking shaft, by
taneously throughout the train, on the release of
means of which the breaks are made to act instan-
a catch or disengaging coupling in the guard's
van. The value of this provision for the im-
mediate and simultaneous action of the whole of
the breaks, in cases where an obstruction is per-
ceived upon the line, will be at once evident.
is one of the most important features of these
It
breaks.

ON EXPERIMENTS TO DETERMINE THE
EFFICIENCY OF CONTINUOUS AND
SELF-ACTING BREAKS FOR RAILWAY
TRAINS.

By WILLIAM FAIRBAIRN, C.E., F.R.S., &c.*
Of late years varions improvements have been
introduced upon railways, to diminish the dangers
of travelling, and attention is now specially directed
to the increase of the retarding power for trains by
various kinds of breaks. From an early period in
the history of railways, it was seen that few
objects were more important for ensuring the
security of passengers, and reducing the loss of
time occasioned by stoppages, than the attainment
of some means of destroying the momentum of
trains with ease and rapidity; that is, in the
least time and in the shortest distance. The less
the time requisite to break a train, the longer the
steam may be kept on in approaching a station
and the less is the loss of time in stopping. And
the shorter the distance in which a train can be
brought to a stand, the less danger is there of
collision with obstructions on the line perceived
not far off ahead. It is already allowed by
many of those connected with railways, and has
been expressly stated by the Lords of the Com-
mittee of Privy Council for Trade, that the
amount of break power habitually supplied to
trains is in most cases insufficient, and their Lord-
ships enumerate thirteen accidents from collision
occurring in 1858, the character of which they
consider would have been materially modified, if
not altogether prevented, by an increased retard-
ing power under the command of the guards of
the trains.

Upon this subject the most important communication hitherto made has been the Report prepared by Colonel Yolland for the Railway Department of the Board of Trade, and containing a large number of experiments with heavy trains at high velocities. The breaks with which Colonel Yolland experimented were those which, as improvements on the common hand break, have hitherto commanded most success.

These were the steam break of Mr. McConnel, the continuous break of Mr. Fay, the continuous and self-acting break of Mr. Newall, and the self-acting buffer break of M. Guerin. The general conclusions to which Colonel Yolland was led by his experiments resulted in the recommendation of the break of Mr Newall; and for heavy traffic, a provisional recommendation of the break of M. Guerin.

From a misunderstanding caused by this Report of Colonel Yolland arose the necessity for some further experiments on the similar breaks of Mr. Fay and Mr. Newall; and these I was called upon to arrange and carry out, by the directors of the Lancashire and Yorkshire Railway. I propose to lay before the Association a brief abstract of these experiments, with some remarks upon the conclusions to which they gave rise.

It will not be necessary here to describe minutely the details of the construction of these breaks. They consist essentially of a series of break blocks acting upon every wheel of the carriages of the whole train or some part of the train, the break blocks being suspended as flaps or placed on side bars beneath each carriage, as in the ordinary arrangement of the guard vans. But whereas it would be both expensive and inefficient to work these breaks with a guard or breaksman to each carriage, both Mr Fay's and Mr. Newall's patents provide for a continuous shaft, carried the whole length of the train beneath the framing, and with suitable jointed couplings between each

*A paper read to the British Association, 1859.

[OCTOBER 7, 1859.

In other respects these experiments were con-
ducted like the preceding, with fog-signals, and
however, was in this case fine and dry, and hence
the time noted by stop watches. The weather,
the following results were obtained in the most
uniform circumstances.

tance of the air, was ascertained to amount with
The friction of the train itself, and the resis-
Mr. Fay's train to 10-4 lbs. per ton.
Mr. Newall's train to 64 lbs. per ton, and with

EXPERIMENTS AT SOUTHPORT.
Slide breaks; Engine detached.

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In carrying out the views of the directors of the
Lancashire and Yorkshire Railway Company, it
was arranged, in order to test the relative efficiency
of these breaks, to have a series of experiments
upon the Oldham incline of 1 in 27 on this
gradient. A train of carriages fitted with Mr.
Newall's self-acting slide breaks, and a similar
train fitted with Mr. Fay's continuous flap breaks,
were started in turn, and after having passed over
gravity, the breaks were applied, and the distance
a measured distance by the action of their own
along the incline in which the trains were respect-
ively brought up was carefully ascertained, as a
measure of the retarding force of each.
trains employed consisted of three weighted
The
carriages each, and having been placed upon the
incline, they were started by removing a stop.
Having then descended a previously measured dis-
tance with a uniformly accelerating velocity, they
passed over a detonating signal, which conveyed
notice to the guard to put on the breaks. Then
the train having been brought to a stand, the dis-
tance from the fog signal to the point at which
the train stopped was measured, and the train
brought back for another experiment. In this
way it was easy to obtain an initial velocity of per hour.
50 feet a second, or 35 miles an hour, before
applying the breaks.

Unfortunately the day upon which these experi-
ments were made proved misty and foggy, with
rain at intervals, so that the rails were in the very
worst condition for facilitating the stoppage of
the train. The significance of this fact will be
breaks in these experiments with those made in
scen on comparing the retarding power of the
fine weather.

force exerted by each break in terms of a unit of
Reducing the results, we find that the retarding
lowing table:-
mass, was equivalent to the numbers in the fol-

EXPERIMENTS ON THE OLDHAM INCLINE.
MR. NEWALL.

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The general result of these experiments gives a
retarding force of 171 lbs. per unit of mass for
Mr. Newall's break, and 185 for Mr. Fay's. Or,

in other words, Mr. Newall's break exerted a re-
tarding force of 121-3 lbs. per ton weight of the
train, and Mr. Fay's a retarding force of 129 lbs.
per ton.

I afterwards arranged for some further experi-
ments at Southport upon a piece of level rail
between that town and Liverpool. The speed
requisite in this case had to be obtained by the
aid of an engine, which was detached by a slip
coupling at the instant of applying the breaks.

6:70

break, and 67 lbs. in Mr. Fay's. Or, in other In this case we have a retarding force per unit words, the retarding force of the slide breaks of of mass equivalent to 549 lbs. in Mr. Newall's lent to 382-6 lbs. per ton weight of the train. Mr. Newall, from eight experiments, at velocities The retarding force of Mr. Fay's slide break varying from 35 to 60 miles an hour, was equivafrom eight similar experiments, at velocities from 33 to 63 miles per hour, was equivalent to 466-4 lbs. per ton weight of the train.

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These experiments give for the retarding force of Mr. Newall's flap break 6.32 lbs. per unit of mass, and for Mr. Fay's, 5.87 lbs.

Or, in other words, the retarding force of Mr. velocities varying from 50 to 511 miles per hour, Newall's flap break, from three experiments at was equivalent to 410-3 lbs. per ton weight of the train.

The retarding force of Mr. Fay's flap breaks, from three similar experiments, was 408 6 lbs. per ton.

We may illustrate the general bearing of these experiments by estimating from an average of the whole experiments the distance required to stop a train fitted with these breaks, and detached from the engine:

A train would be stopped at a velocity of 20 miles an hour in 23-4 yards.

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69 This last table exhibits, in a very clear manner, the advantages of this class of breaks, in which the momentum of the mass instead of the weight of whole weight of the train aids in destroying the one or two guard vans only. It may be impos carriage; but at all events, in the ordinary traffic, sible in long trains to apply these breaks to every three times the present amount of break power may be employed with ease.

pears to encourage its application. From experiOn the score of economy, also, the system ap. ments which have been made it appears that the because the springs may be so adjusted as not to wear of the tyres is far more uniform and equal, cause the wheels to skid. The manager of the

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It will be observed that on most through lines

that the trains travel on some portion of the distance at the rate of 60 miles an hour; and in the

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matters which formerly went to maintain the
fertility of the soil. Nor was it necessary to re-
mind the members of that section that agricul-
turists had to resort to another hemisphere to
make up the deficiency. So obvious had this evil
become, that the aid of chemistry had been
universally called for to devise some means of
entrapping the riches which were thus squandered

in the ocean.

Although prophecies as to the results of contemporaneous operations were attended with considerable risk, yet he would venture to predict, that the chemical efforts now being made to utilise sewage matters must prove abortive, simply because they were commenced at the wrong end of the sewer. That modes were known to chemists fully equal to the extraction of all the nitrogenous and phosphoric constituents of diluted sewage, there could be no doubt.

The real question, as regarded any of these operations, was not as to whether it could be done, but whether, when done, the products would repay the cost of obtaining them-a consummation which was far from probable. At the same time the if the attempts to utilise these matters were chances of success would be found much greater previous to what he regarded as their destructive undertaken at less distance from their source, and the effect of causing the inhabitants of towns to dilution with water. As it was, however, this had that which they formerly obtained in sufficient resort to distant quarters for water, to replace

abundance from the rivers.

collision would be inevitable unless the driver has
the power and the presence of mind to act with
promptitude. Now, at 60 miles an hour there is
only 30 seconds, or half-a-minute, to effect that ob-
ject, and it is quite impossible to apply the breaks
in their present state before the train-in such a
precarious position-is in actual contact. Assum
ing, however, that breaks upon the principle of
Newall and Fay were attached to the engine as
well as the train, and that the driver had the
As already stated, shallow springs were be-
power of instantaneous application by liberating a
coming extinct, whilst supplies from wells could
spring, it is evident that instead of the train dash-only be obtained by carrying them to greater
ing forward to destruction, the momentum might
be destroyed in a distance of less than 500 yards,
and that without injury to life or property. Be-
sides, the application of the electric telegraph,
which prevents on most through lines more than
one train being on the line between the stations,
is a great additional security, and that united to
the continuous break applied to the engine as well
as the train would, when united to a more perfect
system of signals, render collision next to impos-

sible.

ON THE SUPPLY AND PURIFICATION
OF WATER.

By THOMAS SPENCER, Esq., F.C.S., &c.
THE author of this paper set out by stating that
from an extended practice for a number of years
in relation to the chemistry of water for the
supply of towns, he became convinced that the
available quantity of pure water in these islands
was decreasing, whilst it was evident the demand
for this primary necessary of life was undergoing
an annual increase. In short, that in the more
cultivated districts the supply was every year
becoming less capable of meeting the demand.

From continuous personal observation of many of the water-bearing districts of Great Britain, he had now found many shallow springs dried up, or gradually becoming so, whilst the beds of small streams, where water was formerly known to flow pretty regularly, were almost dry, except in times of flood. This had a corresponding effect on the depth of the water of most rivers, but was especially felt of late years in those that were navigable.

The bearing of this state of things on our available water was to increase the quantity of its organic impurity, inversely with the amount of its supply. These effects he would show were chiefly due to increasing drainage.

An additional and most important source of the impurity of river water arose from the now legalised efflux of excremental matters into common sewers, and thence into rivers, by which they were rendered equally fertile sources of disease to the cesspools they had superseded. In short, wherever population was, running waters were becoming more and more polluted with the The British Association, September 17th. Section B. -Chemistry. President-Dr. Lyon Playfair, C.B., F.R.S.

depths, and those had to be sunk far apart, to
ensure an extended conoid of percolation. Mr.
Spencer then proceeded to show that the causes
of this general diminution of spring water was
almost entirely due to the vastly increased
drainage that had taken place of late years. The
greater part of the rain that was formerly allowed
to percolate the substratification, and thence issue
off the land by means of deep drainage, and drain
at lower levels as spring water, was now carried
pipes, into the adjoining brooks in a few hours.

The contrast between this and the former state
of things was described as being not unlike that
witnessed after rain had fallen on two roofs, the
one thatched, the other slated. For hours after
the thatch, whilst a few minutes served to obli-
the last shower water trickled from the eaves of
terate all traces of moisture from the slates.

But in addition to this, the same condition of things had the important effect of diminishing our rainfall as well, so that not only was it rapidly carried off the land, but as a direct consequence, every year drainage had less water to deal with. This result arose as follows:-The larger amount of dry surface resulting from excessive drainage had two distinct effects, each dependent on the other. One was to diminish the clouds, whilst the same absence of moist surfaces amount of evaporation, and thereby cause fewer prevented clouds from other quarters being attracted, consequently their aqueous contents were not so liable to be discharged on the now well-drained tracts as formerly.

on

Though the operation of these circumstances our climate was described at considerable length, yet this part of the subject was alone so extensive as to cause the author to leave many important points untouched. In concluding the briefly exemplify the principles he had set forth, first part of his communication, that he might ing of formerly moist or ill-drained districts in Mr. Spencer put it to his auditory, if, when speakrecently discovered tracts, they did not constantly effected on climate by cutting down forests, and hear of the meliorating influence which had been draining marshes, and, was not this always followed by a lessening of rainfall? And again: if these sources of evaporation were thus cut off, was it not obvious that the natural process of cloudforming must. to that extent be decreased, and therefore less rain be likely to fall? Besides,

were not most observers agreed in opinion, that moisture, and as a consequence, is their rain not clouds are attracted wherever there is wide-spread discharged more abundantly and frequently at those parts of the surface, than where moisture to the same extent does not exist?

In corroboration of what had been stated, he
added, that the most reliable meteorological obser-
vations of the last forty years exhibited a con-
tinuous decrease of rainfall, at least in the more
southern parts of this island; whilst during the
been steadily advancing.
same period the extent of the drainage area had
The author had no
intention of doubting that the benefits of improved
drainage were of a high character, and almost
equally so those arising from the absence of ac-
cumulations of filth near our dwellings. Both
were the inevitable results of our advancing civi-
lisation, though each might be made to undergo
some wholesome modification. Meanwhile, great
as their benefits undoubtedly were, his present
object would be attained if he succeeded in calling
attention to the vast though hitherto overlooked
cost at which they were obtained.

gether with the probable effects of sewer water
His opinions as to the results of drainage, to-
published by the author in 1816..
on the quality of our domestic supply, were first
Since that
period all his very ample opportunities for practi-
cal observation have added certainty to the
evident that the quantity, as well as the general
opinions he had then set forth. It being thus
quality of our water supply was rapidly deteriorat-
ing, it struck him that some efficient and cheap
mode of effecting its purification would be
attended with great public benefit. Accordingly,
in 1854, he began to devote himself to the subject,
which he had now brought, he trusted, to a suc-
cessful issue.

At the commencement of his researches, the
opinions of all the authorities with regard to the
probability of purifying water by artificial means,
were summed up at the conclusion of the report
drawn up by the Government Commissioners,
These gentlemen there said:
"On the supply of water to the Metropolis."
cannot be deprived of matter held in solution by
"That water
tion." This was the stateof the subject when
any practical modification of the process of filtra-
entered on by him. His object, from the begin-
ning, was to discover the mode by which nature
colourless spring water, the operation being
converted impure coloured surface water into
ments were made with a view of throwing some
apparently one of filtration. His first experi-
light, if possible, on the philosophy of filtration
as ordinarily practised, he having some reason to
believe the process, when most effective, did not
generally supposed.
so much depend on mechanical principles as was
To determine this point,

related, which resulted in showing that properly a long series of very interesting experiments were conducted filtration (i.e., where the gravitating power of the water is not in excess) is dependent or other media through which the process is peron a lateral attractive action exercised by the sand formed, this being in addition to the downward action of gravitation. His next object was to discover what bodies in nature exercised this newly-discovered attractive power the best. After trying a number of experiments with various descriptions of rocks and minerals, all of which were described to the section, he found that those containing protoxide of iron (even where it was effected the filtration of water better than any chemically combined with other substances) found the same oxide, when isolated in the state of other. Acting on the idea thus suggested, he "magnetic oxide," not only to free it from tursand, but to effect its decolouration with mar bidity more effectually than an equal thickness of vellous rapidity: whilst the other earthy substances entering into the composition of the same rocks, such as silica and alumina, were, in the latter respect, perfectly inert by themselves. From this it appeared evident that the protoxide of ironas magnetic oxide-a substance which enters into

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