THE MECHANICS' MAGAZINE. LONDON: FRIDAY, AUGUST 28, 1868. THE ABERGELE CATASTROPHE. have become detached on the road, and water, and the height of the centre of the guns applies more especially to heavy goods and will be 11ft. Sin. above the water-line. The ballast trains. In the daytime the brake-van turret is so constructed and arranged that on goods and ballast trains must be seen, as a both the guns have a clear range of fire combrake-van is always the last vehicle on such pletely round the bow to within about 20deg. trains." of the fore and aft line on each side; but one It may be said that although under the gun will be capable of being trained and fired block system the limited mail would have from this line round to a right-aft fire on each been brought up at Abergele, the runaway side, so that one gun, at least, can at all waggons would have rushed into it. But times be brought to bear on every point of the their approach would have been known and horizon. The armour-plating in front of the seen, and they might have been shunted into turret will be 14in. thick, and the remaining a siding. In fact, the whole system is so portion 12in. The teak backing will be 15in. N accident, unparalleled in the history of simple, so easily understood and worked, that thick, and the skin plating is composed of English railway disaster for horror in broke hose two thicknesses each gin, thick. The breastits details, has for the last week excited day lines on which it is in use bear testimony to work is protected by armour 12in. thick, the by day the profoundest pity of the whole its value by their freedom from accident. It backing is 18in., and the double plating each country. It happened to a train-the Irish therefore becomes a matter of serious respon- layer ĝin. thick. The skin plating to which limited mail-which had become proverbial sibility with railway directors when it is con- the armour and backing on the sides are for its safety, and which had never met with sidered that they absolutely have at command attached is composed of two thicknesses of a mishap since it was first started some years the means of establishing safety on their iron each lin. thick. The frames are 10in. since. It needs not that we enter upon the lines. When a proverbially safe train like deep, and are placed 2ft. apart. The plating details of the catastrophe: they have become the limited mail fails in one of its most on the top of the breastwork is 14in. thick, but too familiar to all. Nor, pending the essential points, where is the guarantee of and is in two thicknesses each in. The judicial investigation, shall we stop to inquire safety for any other train on any compara-plating on the deck outside the breastwork into the immediate cause of the accident. tively unprotected line? The knowledge of is 3in. in thickness. Throughout her entire We may, however, look at it from another the safety embodied in the block system length, the ship is provided with a double point of view, and see how far the accident would serve to re-establish public confidence, bottom, the space between the two bottoms comes within the class known as preventible. which has just been most rudely shaken. The at the armour shelf being increased to about And this we shall do irrespective of brakes, knowledge of that safety, too, should prompt 4ft. This, with the overhang of the armour guards' vans, couplings, petroleum, or any railway authorities to adopt the system with- and backing, gives a projection, beyond the of the circumstances attending the Abergele out delay. We do not hesitate to assert that inner bottom, of about 6ft., thereby afforddisaster. In our impression of March 3, the neglect of such a means of safety, when ing considerable protection against the attack 1865, we entered very fully upon the details well known and within reach, shows a cul- of rams. A flying bridge is to be constructed and the merits of the block system of sig-pability which sooner or later must be cor- above the breastwork, and iron trunks fitted nalling on railways. A perusal of that rected by legislative enactment, which will round the ladders communicating with it. It article will show that, by the adoption of that put an end to the reign of carelessness and is intended that the ship shall, on ordinary principle, no such accident as the recent one irresponsibility. occasions, be conned from this bridge, but in could have occurred. Since that time we action she will be conned from an armoured have more than once referred to this system, tower on the turret. She will be fitted with which is the invention of Mr. W. H. Preece, and which has been for several years successfully adopted on the London and SouthWestern and other railways. The present moment, however, seems to us a fitting opportunity for once more stating its principles, and urging upon railway directors the necessity of adopting it-or other equivalent means, if they can be found in order to render travelling safe now that they have made it so expensive. THE MONITOR "GLATTON" AND engines of 500 nominal horse power, capable RAM HOTSPUR." of working up to 3,000. Her estimated speed will be from 94 to 93 knots per hour. She can stow 240 tons of coal, and by using, for the same purpose, the water ballast tanks before mentioned, she will be able to stow over 100 tons in addition. Na recent article on the Navy Estimates we referred to the above ships which the Admiralty propose to build this year (in addition to those we have previously described), and we promised our readers a description of them, The "Hotspur" is intended to be a twin which promise we now fulfil. The "Glatton " screw steam ram. She will be 235ft. in is to be a ship of the monitor type, but em-length, 50ft. in breadth, and her mean draught bodying several novel features of construction, of water will be 21ft.; builder's tonnage, Mr. Preece's block system of signalling is and will undoubtedly be an exceedingly for- 2,637 18-94. She will be fitted with engines based upon electric principles, and its object midable instrument of war. She is intended of 600 nominal horse power, but intended to is to prevent more than one train or engine to mount two 25-ton guns in a single turret, work up to 3,600, and she is estimated to from running between any two signal stations and these guns will possess a very extended realize a speed of nearly twelve knots an hour. on the same line at the same time. This is range of fire. The principal feature of novelty It is the intention of the Admiralty that she accomplished by signalling the approach, de- consists in the construction of what may be should be used only in war time, and then parture, and arrival of every engine or train termed a breastwork (first applied in the chiefly as a ram and she is intended to be so from station to station, and by not allowing" Cerberus,") rising to the height of 6ft. 6in. formidable in this description of naval fighting any other train or engine to leave a signal above the deck, strongly armoured, enclosing, as to be the terror of every foe afloat, the station until the previous train or engine has and thereby protecting, the base of the turret, total weight of the ship, considered as a actually passed the signal station next in the lower part of the funnel, the hatchways, projectile, being 4,300 tons. advance. For this purpose a bell communi- and any and all other openings which may cation is provided between each station, and come within it. The guns will be fired over an electric "danger" (or "all clear") signal the top of this breastwork, and they will, in worked from the next signal station for the consequence, be raised to a height which will protection of each line of rails. When this give the ship great advantages when in action. system is carried out strictly and carefully, The "Glatton" will be 245ft. long, 49ft. no collision can possibly take place. Apply-broad (exclusive of armour), and 2,709 tons ing the principles of working thus laid down builder's tonnage. She will draw 19ft. of to the late catastrophe at Abergele, we at once see how it could not have occurred had the block system been adopted on the line. The rule is that the "all clear" signal is not to be given until the station at which a train has arrived is actually clear and ready to receive another train on the same line. It therefore follows that while the goods train remained at Llanddulas, no train could pass Abergele. This point is very carefully provided for in the instructions framed by the railway companies upon whose lines the block system is in use. This will at once be seen from the following rule (No. 3), which we take from the South-Western Railway code: "All signalmen, or other persons in charge of the signalling instruments, before giving the 'all clear' signal, must take care to have seen the tail lamps of the train or engine after its arrival. This is to provide against danger in case any portion of the train may water both forward and aft when not in action; The "Glatton" is intended, when in action, The "Hotspur" will, however, be a dangerous antagonist irrespective of her immense ramming powers. She is to carry a large gun in a fixed battery, protected by armour plates Sin. in thickness, with 10in. of teak backing. The gun is mounted on a turntable, and is so fixed or adjusted, and the battery is so constructed and arranged, that the gun commands an unobstructed arc of fire from right ahead to 45deg. abaft the beam on each side. The sides of the ship from the lower deck, which is 18in. above the water, to 5ft. below the water, is covered with armour, the upper strake being 11in. thick, and the lower one 8in., the armour resting on a teak backing 15in. and 12in. thick. An upper structure is erected above this lower deck, standing 12ft. out of the water. This upper structure consists of a central breastwork, protected by 8in. armour, and it is on the top of this structure, at the fore end, that the before-mentioned fixed battery is placed, roomy 'tween decks being constructed forward and aft. This breastwork is intended to serve similar purposes to those previously mentioned in reference to the "Glatton." The lower deck outside the breastwork, is plated with iron 3in. thick amidships, reduced to 24in. at the bow and to 2in. at the stern, and is thereby ren men. dered both bombproof and waterproof. The ship will be very lightly rigged, will carry 300 tons of coal and one month's provisions and stores for a crew of 175, including officers and The foregoing is a brief, but accurate, description of the monitor and ram which the Admiralty have decided upon adding to the British navy during the present year; and whatever may be the characteristics of the majority of our future ships of war, we think the "Glatton" and "Hotspur" cannot but prove important auxiliaries to the operations of any fleet. The "Hotspur" would unquestionably prove a formidable antagonist when fighting end-on with her 18-ton gun, offering herself but a small target for the guns of her enemy, and should she succeed in delivering a fair blow with her ram bow, her opponent must certainly go to the bottom. Being supplied with twin screws will add greatly to her manoeuvring powers, and materially contribute to her answering the purposes for which she is intended. UTILIZATION OF STORM WATERS IN FRANCE. from one-fifth to one-third. Several acres have reinforcing of the rim, thus strengthening the ourselves. THE manure. THE AMERICAN CENTRAL-FIRE SERVICE CARTRIDGE. In de of our metropolitan drainage, that of Paris TF English service cartridge occupied bar of tinned iron, pressed closely against the some of our attention last week, not in head of the case. Although not then in its is very incomplete, and by no means up to the way of description, for its details are well perfected state, the arrangement gave unwhat we should regard as a proper standard known, but in considering how very nicely doubted evidence of great superiority, and for so fine a city. The important question our authorities managed not to promote the its subsequent success has proved the wisdom of purifying the contents of their sewers, and introduction of a cartridge which, outside of its adoption by the department. utilizing them as a manure, has for some time official circles, is known to be the best we veloping and perfecting this cartridge, exengaged the attention of many of the savants have. We now purpose placing before our tended experiments were made to determine and engineers in Paris. During the last two readers the history and manufacturing details the best quality of material to be used, the years the municipal authorities have grauted of the metallic-case central-fire cartridge in proportions of the different parts of the cardivers sums for the purpose of defraying the use in the American army. The successful tridge case and anvil, the surest and safest cost of some reliable experiments in connec-invention of the self-primed metallic-case process for accomplishing the most perfect tion with the subject. A double object was cartridge has greatly simplified the construc- work, and the condition and efficiency of the to be obtained by the execution of any pro- tion of breech-loading small arms. Prior to finished cartridge. These trials had to be ject that embraced the desired end. One was its introduction and use, the prevention of prosecuted pari passu with the designing and to put an end to the evil resulting from the the escape of flame through the joint of the building of special machinery to perform discharge into the Seine of the contents of breech was of difficult--if not impossible-ac- with economy the most exact and delicate the sewers, and the other to utilize them when complishment, and completed arrangements operations, and with the actual manufacture intercepted, and distribute them over land to of the breech mechanism had to be resorted of the ammunition itself, to meet wants of -produce a fertilizing effect as a valuable to with, at best, unsatisfactory results. The the troops that were about to be armed with Net only would the advantage metallic cartridge overcomes this difficulty, the new weapon. Notwithstanding all this, viewed in this light be of a twofold nature, being itself a perfect gas-check renewed at the reports from commanders, both in garbut the public health and agricultural pros-every round, prevents foulness and wear of rison and in the field, are conclusive as to perity would be likewise benefited by it. the mechanism, and exercises the most vital the merits of this ammunition. Bearing in mind what had been done in Eng-functions in the life of the arm. So im- In the early part of the manufacture attenland with respect to utilization of sewage, portant an element is it, that it may be said tion was directed to the necessity of reinforc and the great value of the irrigation system that, with a perfect cartridge, the most in- ing the head of the case, where its weakest carried on in Italy and Spain, the Parisians different breech arrangement can be used point is subjected to the severest strain, and commenced their operations upon a single with safety and efficiency. Its advantages, where its bursting would endanger the piece of ground near to the discharging main other than that already indicated, are many; stability of the breech arrangement. Colonel sewer at Asnières. In order to give the matter its completeness and simplicity, being self- Benton, of the Ordnance Department, suga perfectly fair trial, it was determined to primed, and used as a whole in loading; its gested the use of a thin copper cup in comseparate the mode of proceeding into two dis- strength and safety, withstanding the bination with the bar anvil, the cup acting as tinct sections; in the one, the water was roughest usage and thoroughly protecting a reinforce to resist the first action of the treated with chemical reagents, and thus par- the powder and fulminate; its accuracy, be- powder and fulminate, and render the yieldtially purified; in the other, the irrigation cause of the coincidence of the axes of the ing of the head impossible. was carried on direct from the discharging bore and bullet; and, added to these, the ab-however, two objections to its adoption-the outlet, without any preliminary purification. solute impossibility of using more than one liability to miss-fires from having two thickThe latter plan will unquestionably be found cartridge at a time. As we have already in- nesses of metal in the head, and the increased the preferable, as all the expense and uncer- dicated, the cartridge adopted by the United difficulty and expense of manufacture due to tainty of the clarifying process will be saved. | States Ordnance Department is on the its complication. Lieutenant-Colonel Benet, At the same time, it is frequently necessary to central-fire system. The superiority of this commanding the department-to whom is provide settling tanks, for the water to deposit system over the rim-fire is so marked as will due the credit of perfecting this cartridgesome of the heavier particles held in solution, undoubtedly lead to its universal adoption. thought it possible, however, that the cup before it is permitted to flow over the land. By concentrating the percussion composition itself might be made to perform the addiThe chemical process adopted at Asnières in the centre of the head, the quantity used tional work of the anvil, and thus overcome consists in the treatment of the sewer water is reduced to a minimum-to less than one- the objections by dispensing with the bar. with sulphate of alumina, fourteen grains fourth of what is required to prime the entire After repeated trials with cups of different per gallon being sufficient to precipitate the circumference in the rim-fire; and this metals and forms, the one made of sheet suspended ingredients, and effect the purifi- smaller quantity is so much better protected tinned iron was found to possess all the qualication of the liquid. The purifying tanks as not to be at all liable to accidental explo- ties required, and has been adopted. have been for some time in regular operation, sions. The central portion of the head has doubt exists of its being a marked improveand their success has been most satisfactory. more elasticity than the rim, and is betterment, and frequent firings with charges vary Fina There were, Νο the results have been as follows: able to resist the strain upon it from the ing from 70 to 100 grains of strong rifle manure selis at fifteen shillings the sudden action of the fulminate, besides having powder show its strength to resist far ton, and the cost of its production varies the additional advantage of permitting the heavier strains than any to which it can be ticulars. they are fed through a vertical trough at the The re subjected by the largest charges used in ser- water, using a revolving wire barrel par- crimped under the edge of the cup. Each vice. Colonel Benet has lately reported tially immersed in it. The cleansed tubes machine will taper thirty-five cases a minute. fully to General Dyer, Chief of Ordnance, are then taken to the heading machine, where The cases are now ready to receive the on the manufacture of these cartridges, as the head or rim is formed. A punch, having powder charge and the bullet. They are well as upon the results of such trials and ex- a shoulder at a distance from its extremity loaded by means of a loading machine, which periments as have been made from time to equal to the interior length of the headed consists of a revolving circular plate with time to test the efficiency and reliability of case, forces the tube into a die having a holes or receivers, and a hopper and powder the work done. From this report, dated countersink at the other end, of the size of measure. The cases and bullets are fed on May 13, 1868, which has just reached us, we the rim to be made. The heading punch revolving plates, thirty-five a minute; the are enabled to gather the following par- then presses and spreads the unsupported former are lifted into the receivers, pass under projecting portion of the tube into the the hopper and measure for a charge of powThe sheet copper from which the cases are countersink, thus forming the rim. No oil der, and then under the bullet-feeder for a made is No. 22 wire gauge, obtained in strips is used in this operation, the moisture on the lubricated bullet. In order to insure a full 3ft. long, from which circular discs 1.7in. in tubes, as they come from the washing barrel, charge in cach cartridge, the machine is prodiameter are punched to form the case. One suffices as a lubricant for the purpose. The vided with a bell which gives notice to the pound of copper gives thirty-eight discs with machine is fed through an inclined trough, operative of any failure in this particular. 3 ounces of scrap. The copper is not pure at the rate of sixty-five a minute. The cases The edge of the case is then crimped on the as received from the mills, but is alloyed with are now finished, but in order to insure the bullet, in a very simple manner. five per cent. of spelter. The best ore is thorough removal of every particle of oil, ceivers are smaller at the top where the bullet mined on the shores of Lake Superior; the they, now undergo another washing in the enters than at the bottom where the case is Minnesota mines, and next, the most ap-alkaline solution, after which they are ready received, the diameter of the former being proved brands of Detroit smelting, are se- for loading and priming. only equal to that of the interior of the open lected in preparing the metal for cartridge We will now turn to another department, end of the latter. After the bullet has been purposes. The copper strips are rolled in and follow the manufacture of the anvil cups. pressed into the case, the cartridge is lifted, the most careful manner, of an even thick- These cups are made sufficiently rigid to so that the edge of the case is forced into the ness throughout—a very important considera- resist the blow of the hammer communicated conical surface of the receiver, between its tion-and are entirely free from seams, through the firing pin which explodes the larger and smaller diameters. The powder is blisters, or flaws of any kind, and well percussion composition. Their form is such placed in a pasteboard hopper, about 2ft. annealed. The discs are punched from the as to force the flame to pass through the above the machine, and is fed to the cases copper strip and formed into cups, by means vents and ignite the charge. They are made through a paper tube lin. in diameter; the of the double-action press. Two or more by a double-action press, from sheet tin-hopper and tubes stand inside a large conical rows are cut, according to the width of the plate, No. 20 wire gauge, made of the best shield of boiler iron. After loading, the strip, one disc at a time, at the rate of charcoal iron, free from all defects, having a cartridges are wiped clean, and packed in seventy-five a minute, the copper being fed bright and smooth surface, and being of uni- paper packages and wooden boxes, for by hand. In order to draw out these cups form thickness throughout. One pound gives storage or issue. to the dimensions required in the finished 150 cups and 5 ounces of scrap. Thus made. We have now followed the manufacture of case, they are subjected to the action of four the cups are of the right diameter, but too the American service cartridge through all additional punches and dies, of different long, and with ragged edges. These are cut its stages, and have seen the mechanical sizes, so as gradually to elongate the sides of off and the cups reduced to an exact height appliances used in the various processes. the tubes while reducing the diameter. of 2in., by means of the trimmer, to which The mechanical arrangements, no less than These draws are made by single-action the results, reflect great credit upon the presses, each provided with a single punch heads of the department. During the proand die. The last, or finishing draw, leaves cess of manufacture accidents are only the case with the exterior diameter required, possible with the loading machine, and the extreme variation of which is 002in. pleasure. The two vents are then made by a consequently every precaution has been These machines are fed at the rate of sixty-small punching machine, with double punches taken to provide against their occurrence. five tubes a minute, by placing the latter on and dies, the cups being fed on a revolving As the machine is now made and arranged, a revolving horizontal plate provided with circular plate at the rate of sixty a minute. the explosion of one cartridge may communiguides and stops. After the second draw, The newly-cut edges of the cup and vents cate fire to the few charged cases near it, the tubes are annealed in order to restore to exposing the iron to oxidation, the cups are without danger. The entire charge of powder the metal its ductility, the previous opera- now re-tinned to cover the parts exposed, in the hopper may be thus exploded, without tions having rendered it hard and brittle. after which the recess or cavity on the out- the possibility of injury, either to the operaThe number of annealings required during side, for the reception of the percussion com- tive or to the machine, as the hopper and the entire process of manufacture, depends position, is made by the impression machine. tube offer but slight resistance to the action on the quality of the metal used; with the This is in its general features like a header, of the gases, that expend their forces in every best copper only one is necessary. The an- and not only forms the recess but also gauges direction, without affecting the stability of nealing is done by placing the tubes in a the cup, at the rate of eighty a minute. The the protecting shield. This has been proved perforated iron cylinder, heating them red-cups thus completed are well washed in the by experimentally ploding full charges of hot in a charcoal fire, revolving the cylinder alkaline solution to remove the oil, and when 241b, in the hopper itself. But the explosion meanwhile to equalize the heat, then plung- thoroughly dried are ready for priming. of a cartridge in the operation of loading is ing them into a solution of one part sulphuric The percussion composition used in prim- of very rare occurrence, for out of nearly five acid and fifteen parts water, and, afterwards, ing is of the consistency of thick paste, and millions loaded in the past six months, only thoroughly washing in several changes of is deposited in the recess. cavity of the cup two are reported to have exploded premawater to remove all trace of acid. The acid by means of a priving machine. This is a turely, resulting in no damage whatever. solution (pickle) cleanses the metal from any very ingenious piece of mechanism, which has Such satisfactory results have only been scale or oxide occasioned by the annealing. only just been completed, and which per- attained by carefully working out all the After undergoing these operations, the forms the important operation of priming mechanical details, the description of which tubes, being of unequal length, and havin with the greatest accuracy and certainty and forms a most interesting chapter in the ragged edges, require trimming up, The most perfect safety. It consists essentially history of small arm cartridges. ends are, therefore, cut off, and the tubes re- of a circular plate and a number of upduced to a fixed uniform length, so as to right stems on which the cups are placed. facilitate the subsequent operations, and in- These are brought in succession under a A NEW CHALMERS TARGET. sure exact and accurate work. This cutting tube-feeder that deposits in the recess the is done by the trimmer, which consists of a composition previously taken up at the AD the recent experiments at Shoeburyrevolving mandrel with a shoulder, on which magazine. The principal difficulty heretoness been at all decisive of the contest the tubes are placed, and against which the fore encountered in perfecting a machine of between guns and armour, we should have felt edge of a revolving circular cutter is pressed. the kind is entirely overcome by the use of it to be our duty to discountenance, as far as The edges are thus cut clean and even, at this peculiar feeder. It primes at the rate of lay in our power, the construction of any more the rate of thirty a minute. The lubricant thirty-five a minute, doing the work of three expensive targets at present. But as the used throughout all these operations is the hand operatives. While the composition is question now stands, we are not surprised to best lard oil, but at this stage of the process still moist, the primed cups are put into the learn that Sir John Pakington has sanctioned it is of the greatest importance that all trace headed cases and crimped in position, the the construction of another target on the of it be entirely removed from the tubes, cases being tapered at the same time. This Chalmers system. Indeed, we are rather suras the smallest particle remaining would is done by the tapering machine, which con- prised that this has not been done long ago. destroy the percussion composition if it sists of a revolving horizontal plate with four It is now more than six years since this plan should come in contact with it. The oil is tapered dies, through which project stems was first brought under the notice of the successfully removed by washing the tubes having a vertical motion. The primed cups Admiralty. The first Chalmers target was in a solution of 1 lb. potash, 14lb. soda, and are put on the ends of these stems, the cases five gallons of water, at a temperature of over them, and both forced into the tapered 120deg., for seven minutes, and afterwards dies, pressing each cup hard against the head rinsing them thoroughly in clean warm of the case while the sides of the latter are H tried, we believe, in April, 1863, and the Iron Plate Committee reported that it resisted a greater weight of shot with less injury than any other target designed for naval purposes. The Ordnance Select Committee, at a later period, were no less decisive in their reports in its favour; and yet the system was quietly passed over- -pushed aside, as it were-to make room for the laminated principle adopted in the Gibraltar shields and the Plymouth Fort. Even now, it appears that Mr. Chalmers's system is not to be allowed to compete with any official plan in either department of the service. The new target, we believe, is to be a naval target, but its competitor is to be a new 8-inch "Warrior" target, which does not represent any ship in the navy. It is the type of target used two years back by the Ördnance Select Committee to test the new Palliser projectiles. And the chief object now is to ascertain what advantages have been gained by the alteration in the form of the Palliser shot from an ogival head of one diameter to a head of 14 diameter. The Ordnance Select Committee's target had an 8-inch plate, 18in. of teak backing, and a in. skin; and Mr. Chalmers is to be allowed the same weight of iron and depth of structure. His thickest plate will only be 44in., and if it compete successfully with the 8-inch plate of the Committee's target, it will be entirely owing to the nice combination of elasticity and rigidity in the compound backing. When the original Chalmers target was tried, it was stated in these columns that "It stood the brunt of the firing better than the Warrior' target," and that in resisting the salvo of five guns "it carried away the palm" from all its predecessors. But we were also compelled to record a round, fired from the 104-inch gun with solid steel shot of 301lb. and 45lb. of powder-a test the target was not designed to stand, from which nothing useful could possibly be learnt, and which only served to postpone for some years the adoption of an invention well calculated to improve our national defences. Let us hope that the new target will receive a fairer trial. ELECTRICITY AND TELEGRAPHY. Na severe thunderstorm that occurred at the results of a severe thunderstorm that passed required note is struck, and so, from a series of M. Gaiffe, the well-known Parisian philosophical instrument maker, in experimenting upon the coke used round the carbon in the Leclanché that the diminution of the internal resistance of battery (see our number of March 13), concludes the battery, and its great constancy, are due to the broken coke considerably augmenting the surface of the carbon element, and consequently lessening its distance from the porous vase. The deflection obtained by him on a large wire galvanometer was 28deg.; and at the end of twenty-four hours, the circuit being uninterrupted and a constant current flowing, the deflection was 27deg., or a loss of deg. only. The following plan has been suggested by M. Sumner for the prevention of fearful explosions by fire-damp. An insulated wire, broken at sundry points, every here and there, is fixed near the roof The Electric and International Telegraph Com- of the different galleries of a coal mine. The two pany have issued a circular to their shareholders, ends of the wire are carried out of the mine, and summoning a meeting for the 8th of September, are connected with a powerful Rhumkorff's coil "for the purpose of considering, and if so resolved, and battery. It is expected, in setting the appaof authorizing the board to sell and convey to her ratus into action, that at each interruption in the Majesty's Postmaster-General, in his corporate continuity of the wire a spark will constantly be capacity, and to his successors, and to require flashing, and will have, for effect, the combustion of him to purchase, the undertaking of the company, the fire-damp in minute quantities, so that it would upon the terms and under the powers and pro-be impossible for any sufficiently dangerous quanvisions contained in the Telegraph Act, 1868." We learn that the laying of a cable between bill for that purpose having passed the Jamaica Jamaica and Cuba is about to be undertaken, the Assembly. tity of fire-damp to accumulate, for as soon as any gas was evolved it would be harmlessly ignited by that its practicability will be interfered with in the spark. The idea is novel, but it will be found various ways. For any plan to be adopted for pro- At a recent meeting of the "Societé d'Encourage-NOTES ON RECENT SCIENTIFIC DISCOVERIES AND THEIR PRACTICAL APPLICATIONS. I Nantes, on the 20th ult, a lady found her pallo," the invention of M. Spiess. The forces and SIMPLE GAS REGULATOR-MICA POWDER FOR LINING self completely enveloped in a kind of luminous atmosphere. She carried an ordinary Porte monnaie, containing some pieces of silver, and a piece of gold in the interior division. The two metals were consequently separated by the material forming the division. FIREPROOF SAFES-BRICKS OF COKE AND ASHES- Several mechanical inventions have been at times brought forward for producing music on a piano; in all of them, the piano has, however, not been interfered with, and generally these several plans have necessitated a great deal of labour. A great merit in the present invention is the general MR. DEXTER, in the "American Journal of absence of manual labour, clockwork and electri- Science," describes a very simple form of The silver pieces bore dis-city performing the necessary functions. The gas regulator, applicable when only a small numtinet marks of the electric effect, but the gold ordinary playing upon the keyboard of the piano ber of burners is employed. It consists of a gaspiece was covered with a uniform but unpolished is in no way interfered with. The electrical arrange-holder of zine, about 9in. in height and diameter. ments consist in the interior of the piano of a coating of silver, which had been carried through series of electro-magnets, which act upon the or- The bell is connected with the cock through which the division. After dissolving a small piece of the dinary hammer that strikes the wires; these ham- the gas enters by a jointed rod. By this silver in azotic acid, the surface of the gold was mers communicate ir the ordinary way with the means, as the bell rises, the cock is closed and the found to have lost its polish, and presented cha- keyboard, but on their opposite side they have racteristics of fusing. small wooden rods terminating with armatures supply cut off; as the gas is consumed, and the bell sinks, the tap is opened. Thus a very uniform prossure is maintained. Mr. Dexter finds that the difference of weight in the bell, from greater or los immersion, is almost inappreciable. The practical uniformity of the pressure maintained is shown by the fact that when the outlet is suddenly opened to its full extent, such a slight diminution takes place that it can only be seen on the gauge mends that the gasholder should not be painted; by the help of a microscope. Mr. Dexter recomasphalte varnish, he says, is a much better mate In a pamphlet, recently published "On the construction of lightning protectors," Mons. Mézillac What is termed the directing organ consists of being credited with its authorship, the following following mochanical arrangements for directing translation of a passage will not prove uninterest-intermediate roller of metal. The paper specially the current. First, two wooden rollers with an ing: "St. Peter's, of Rome, is of all the prepared with a series of holes placed in positions edifices of the world, the best provided with representing the several notes is rolled around one lightning conductors, and that in which they are of the wooden rollers; passing over the metal situated with the greatest intelligence. In this wooden roller; this unwinding keeps it always at roller, it is drawn off and wound round the second forest of points every rod has its own conductor, a uniform tension. Second, a clockwork moveand, besides, they are all bound together, so that ment for giving motion to the rollers. Third, a each point acts with the sum of the power of all small keyboard with small movable copper ham-rial for coating it. mers; this keyboard is placed above the interme- Mica is known to be one of the worst conductors the conductors. I often ascended, during violent diate roller, so that the small heads of the hammers of heat we are acquainted with. For this reason thunderstorms, upon the immense roof of this rest upon the band of music. mica powder is to be strongly recommended for basilica, which towers much above all the edifices The battery used consisted of a series of thirty-filling in the walls of fireproof safes. Any one of the town, to observe the play of the points, and six Daniell's cells, and the action of the instrument wishing to assure himself of its value for this purtheir action upon the clouds. I saw the most may be simply stated. One pole of the battery is pose can do so by taking a cast-iron tube 2in. or menacing clouds directing themselves rapidly in connection with the small keyboard, the other 3in. in diameter, placing a roll of paper in the above the church; I saw the aigrette shine at the through the various electro-magnets of the piano centre, filling up the space between the paper and extremities of the points; and these clouds, which with the metallic roller. These rollers, being set the walls of the tube with the mica powder, and had made their appearance sending forth flashes in motion by the clockwork, cause the prepared after well closing the ends, throwing it into a furof lightning from all points, departing at the end face and keeping it redhot for some time. When of several instants, silent and inoffensive, without the tube is re-opened after this the paper will be ever a flash of lightning being carried to any of found quite uninjured by the heat at least, 50 says a writer in "Dingler's Polytechnic Journal": and we see no reason to doubt his word. band to be unrolled and pass on the metallic roller. Whenever a hole in the paper comes under the keyboard, the lightly-resting hammer at once makes contact, a current passes through to the The above account contrasts very forcibly with electro-magnet, which attracts the hammer and the the rods." Breeze is no strange ingredient in bricks around London, but Dr. Wagner comes forward with a simple plan for making bricks almost entirely of ashes and coke. The coke is broken into very small pieces, then mixed with the ashes, and afterwards with one-tenth their weight of slaked lime and sufficient water to make a plastic mass, which is to be well worked together, and left for a day or two to set into a proper consistence for moulding. The bricks are now made (a good pressure being employed), and they are set on planks to dry and harden, but they must not be allowed to dry too rapidly. In ordinary times they will be ready for use in about fourteen days. They make very light and dry walls, and, according to the Doctor, make very good facing bricks. Bottger gives a process for getting a bright coating of platinum on brass, copper, and other metals, which does not look to us altogether new, but as some of the directions seem novel we may quote them. He first makes a nearly neutral solution of chloride of platinum by carefully adding carbonate of soda to the acid solution as long as there is effervescence. To this solution he adds a little glucose and some chloride of sodium, without which latter the platinum would be deposited black. The articles to be coated have only to be immersed in this mixture, but when it is wished to coat a number of small objects-pins, for example-it is recommended to place them in a sort of zinc sieve, and immerse the whole in the solution, heated to about 160deg. Fah. The coating of platinum is deposited almost instantaneously, and the articles have then only to be well washed and dried in warm sawdust. arrangement there has been during the past year struments arranged at Kew, comprising the ther- It has already been mentioned that the compe- The usual monthly absolute determinations of the magnetic elements continue to be made by Mr. Whipple, magnetic assistant; and the self-recording magnetographs are in constant operation as heretofore, also under Mr. Whipple, who has displayed much care and ability in the discharge of his duties. The photographic department, connected with the self-recording instruments, is under the charge of Mr. Page, assisted by Mr. Forster, both of whom discharge their duties very satisfactorily. An arrangement connected with the instrumental clock for shutting off the light every two hours, and thereby increasing the accuracy of the time-scale, originally devised by Mr. Beckley, in connection with the self-recording meteorological instruments, has been adapted to the Kew, and also to the Mauritius and Bombay self-recording magnetographs, and the time-scale of the Kew magnetographs has been made the same as those of the other instruments. It was proposed in the last report that the task of tabulating and reducing the magnetic curves produced at Kew subsequently to January, 1865, should be performed by the staff at Kew working under the direction of Mr. Stewart. In accordance with this resolution 787 curves, being those of the declination from February, 1865, to April, 1867, have been measured for every hour, and the process of reduction of these measurements is well advanced. The work done at Kew at one of the observa tories of the Meteorological Committee consists in keeping the barograph, thermograph, and anemograph furnished by the Meteorological Committee in constant operation. The barograph is erected in the room which contains the magnetographs, and which has a very small range of temperature. The outer part of the thermograph is attached to the north side of the observatory, towards the west, while the anemograph has been erected above the centre of the dome so as not to interfere with the photoheliograph. For the first two of these instruments traces in duplicate are obtained, one set being sent to the Meteorological Office and one retained at Kew; as regard the anemograph, the original records are sent while a copy of these on tracing-paper is retained. The tabulations from the curves of the Kew instruments, and the examination of the results forwarded to Kew from the outlying observatories, so far as this last is not personally done by Mr. Stewart, are performed in a very satisfactory manner by Messrs. Whipple Baker, and Page. Chemists have long been experimenting to obtain a bright green pigment, free from the objections which are brought against the copper and arsenic colours, on account of their poisonous qualities. They naturally turned their attention to chromium, and several compounds of this metal have been patented, the best known and most brilliant of which is the borate, known as Vert de Guignet. This compound is, however, troublesome to make, and costly. Recently, another patent has been taken out in France for obtaining the sesquioxide of chromium of a bright green shade which is said to be superior to the Vert de Guignet. The inventor starts with a solution of any salt of chromium, which he boils with appropriate reagents to obtain the green modification; to this he adds either gelatinous alumina or recently precipitated hydrated oxide, carbonate or sulphide of zinc, in just sufficient quantity to saturate the acid. The reaction The meteorological work of the observatory contakes place quickly, but may be accelerated by tinues in the charge of Mr. Baker, who executes heat. The precipitate has only to be washed and his duties very satisfactorily. Since the Dundee dried, and is ready for use. The colour is said to meeting seventy-eight barometers have been veribe cheap, inasmuch as any chromium salt or residue fied, and seventy-one are at present in hand; 1,139 may be employed in making it. Moreover, it is thermometers have likewise been verified, and perfectly harmless, covers well, and has a brilliant fourteen standard thermometers have been conshade. The inventor calls it "Imperial green." structed for the thermographs of the Meteorological The following directions are given for making Committee. Thirty-two thermograph thermomecement impermeable by air and steam, which is ters have likewise been tested, twenty-four of thesellier, said to be superior to any in use for steam and gas being for the Meteorological Committee, and eight pipes. Six parts of finely powdered graphite, for opticians. The experiments made on aneroid three parts of slaked lime, and eight parts of sul-at Kew, by the request and at the expense of the phate, are mixed with seven parts of boiled oil. Meteorological Committee, have formed the subject The mass must be well kneaded until the mixture of a communication recently made to the Royal is perfect. Society by that body. A new safety lamp has been invented in France. It is really an enclosed moderator lamp with a reservoir of compressed air to feed it. It is said to be applicable for illumination under water, but we are not told how the products of combustion escape, and fail to see how it can answer. Compressed air means a heavy metal reservoir, which miners, probably, will refuse to carry about. THE BRITISH ASSOCIATION. SECTION A.-MATHEMATICAL AND PHYSICAL SCIENCE. PRESIDENT-Professor Tyndall, LL.D., F.R.S., &c. Vice-presidents, Admiral Manners, F.R.A.S., president of the Royal Astronomical Society; Professor H. J. Stephen Smith, F.R.S.; Rev. CanonHeade. Por Stokes, F.R.S.; Dr. Temple Professor Price, F.R.S.; Prosor Willis, F.R.S.; T. P. Gassiott, F.R.S.; and Rev. C. Pritchard, F.R.S. Secretaries-Proissor G. C. Foster, M.A.; R. B. Hayward, M.A.; Rev. R. Harley, F.R.S.; and Rev. — Blacklock. PRESIDENT'S ADDRESS. The Kew heliograph, in charge of Mr. De la Rue, PROFESSOR TYNDALL, in opening the business of the section, said, after a long introductioncontinues to be worked in a satisfactory manner. During the past year 224 negatives have been There have been writers who affirmed that the taken on 140 days. Ninety pictures of the pagoda Pyramids of Egypt were the productions of nature; in Kew Gardens have likewise been taken, in the and in his early youth Alexander Von Humboldt hope of being able, by this means, to determine wrote an essay with the express object of refuting accurately the angular diameter of the snn. Since this notion. We now regard the pyramids as the the last meeting of the Association a series of solar work of men's hands, aided probably by machinery researches, in continuation of the second series, of which no record remains. We picture to ourhas been published (the expense of printing having selves the swarming workers toiling at those vast been defrayed by Mr. De la Rue), entitled, "Re- erections, lifting the inert stones, and, guided by searches on Solar Physics. Appendix to second the volition, the skill, and possibly at times by series. On the Distribution in Heliographic Lati- the whip of the architect, placing the stones in W inaugural address of Dr. Hooker, the presithere moved by it power external to themselves, E last week gave a very full abstract of the tudes of the Sun-spots observed by Carrington; by their proper positions. The blocks in this case dent of the British Association for the Advancement measurements of the Kew pictures for the year and the final form of the pyramid expressed the of Science which has just concluded its thirty- 1864 are approaching completion; when complete thought of its human builder. Let us pass from eighth annual meeting. We now proceed to place they will be communicated to the Royal Society. this illustration of building power to another of a before our readers abstracts of the reports, sec- It is intended to work up rapidly the back years, different kind. When a solution of common salt tional addresses and papers, classifying them in preparatory to a final discussion. is slowly evaporated, the water which holds the our usual manner under the several sectional The time and attention of the observatory staff salt in solution disappears, but the salt itself reheads. Some of these papers, which are of special have been so much absorbed during the last year mains behind. At a certain stage of concentration interest to our readers, and which we can only now with the regular work of the observatory, that the salt can no longer retain the liquid form; its briefly abstract, will be published in extenso at little or no progress has been made in miscellane-particles, or molecules, as they are called, begin some future time, with illustrations. We will first ous experiments. to deposit themselves as minute solids, so minute, give an abstract of the statement of the Committee indeed, as to defy all microscopic power. As of the Kew Observatory, premising that the evaporation continues solidification goes on, and Meteorological Office continues in operation, Kew we finally obtain, through the clustering together being the central observatory, as arranged by the of innumerable molecules, a finite mass of salt of Meteorological Committee appointed by the Council a definite form. What is this form? It sometimes of the Royal Society. In consequence of this seems a mimicry of the architecture of Egypt. WORK DONE AT KEW AS THE CENTRAL OBSER VATORY OF THE METEOROLOGICAL COMMITTEE. In the last report of this committee a short account was given of the principles of construction of the system of self-recording meteorological in |