the dissipation of energy. the factory, or belching forth in terrible profusion | consequences of this fact in his beautiful theory of And what is the measure of its force-what is the sum of its acting energies? I can only tell you what is its equivalent. I can give you the exact measure of its strength, and at your longest leisure you can reduce it to the ordinary standard of mechanical force, and determine the measure in horsepower. How much mechanical labour, can all the men, women and children, all the animals of the earth, and all the locomotives and engines on sea and land perform? The leaf does just as much as all those combined. We are not, however, quite done yet with ve table fibre, for that part of it which does not e into our frames may, notwithstanding, serve as fo for our engines, and by this means be converted useful work. And has not Nature, as if anticipate the wants of our age, provided an almost lites store of such fuel in the vast deposits of en means of which so large a portion of the useful of the world is done? In geological ages this was the fibre of a species of plant, and it has stored up as if for the benefit of generations lita present. direct combustion or otherwise, it will in the process give out a deal of energy. When we bars As far as human convenience is concerned, the wood in our fires we convert this energy into beat different kinds of energy do not stand on the same and when we eat vegetables we assimilate this energy footing, for we can make great use of a head of into our systems, where it ultimately produces bot water, or of the wind, or of mechanical motion of heat and work. We are thus enabled to trace the any kind, but we can make no use whatever of the energy of the sun's rays through every step of the energy represented by equally diffused heat. If one most wonderful process: first of all building up r body is hotter than another, as the boiler of a steam-getable food, in the next place feeding the of e engine is hotter than its condenser, then we can sheep, and lastly through the shape of the very pe make use of this difference of temperature to con- saic but essential joint of beef or mutton enter vert some of the heat into work, but if two sub- into and sustaining these frames of ours. stances are equally hot, even although their particles contain an enormous amount af molecular energy, they will not yield us a single foot-pound of work. Energy is thus of different qualities, mechanical energy being the best, and universal heat the worst; in fact, this latter description of energy may be likened to the dreary waste heap of the universe, in which the effete forms of energy are suffered to accumulate; and, alas! this desolate waste heap is always continuing to increase. But before attempt ing to discuss the probable effect of this process of We have said nothing of the aesthetics of leaves-deterioration upon the present system of things, of their beauty and variety (we must not forget that let us look around us and endeavour to estimate the all flowers are leaves). There is not a leaf in the various sources of energy that have been placed at whole vegetable kingdom that does not excite emo- our disposal. tions of the beautiful, either by its form, colour, or odour. There is beauty in the leaves of the solitary palm, and beauty in those of the dense forest, crowded so thick that beneath them the "shadow hardly moves." Beauty in the microscopic mosscup, as well as in the palm whose leaves expand to 30ft. in circumference-beauty and glory in them all. Not only, then, does the leaf supply all the material wants of man, but it also ministers to his spiritual nature-reveals the character of God, blesses man, makes him nobler, wiser and better. In autumn, when the cold winds blow and the leaves turn yellow and red, it is the popular belief that the frost has coloured and killed the leaves, and caused them to fall away. Not so. We mistake here a coincidence for a cause. The time for frost and for falling leaves is the same-one has no relation to the other. There has been no work of violence wrought-no destruction. The leaf has finished its allotted task, it has built up its appointed cycle, stored up the food for its successors, and now its work is done-Ah! well done. No duty has been neglected; it has finished its course; and now it arrays itself in its most gorgeous hues, for its hour of glory has come, and it rests upon the bosom of its mother earth. May it not teach us here a lessona marvellous lesson-how to live and how to die; how a true life is crowned by a triumphant death? will say, WHAT IS ENERGY ?* THE DISSIPATION OF ENERGY (Concluded from page 416.) AT We reply by quoting the laws discovered by Carnot, Clausius, Thomson, and Rankine, who have all from different points of view been led to the same conclusion, which, alas! is fatal to all hopes of perpetual motion. We may, they tell us, with the greatest ease convert mechanical work into heat, but we cannot by any means convert all the energy of heat back again into mechanical work. In the steam-engine we do what can be done in this way; but it is a very small proportion of the whole energy of the heat that is there converted into work, for a large portion is dissipated, and will continue to be dissipated, however perfect our engine may become. Let the greatest care be taken in the construction and working of a steam-engine, yet shall we not succeed in converting one-fourth of the whole energy of the heat of the coals into mechanical effect. In fact, the process by which work can be converted into heat is not a completely reversible process, and Sir. W. Thomson has worked out the *By BALFOUR STEWART in Nature. To begin with our own frames, we all of us pos- But there are other products of the sun's mo sides food and fuel. The miller who makes &? water-power or of wind-power to grind his e navigator who spreads his sail to catch the are indebted to our luminary equally with the who eats meat or who drives an engine. Fax owing to the sun's rays that water is carried t the atmosphere to be agam precipitated so as to what is called a head of water, and it is also of to the sun's heat that winds agitate the air. W the trivial exception of tidal energy all the wo done in the world is due to the sun, so that we mis look to our luminary as the great source of all t energy. Intimately linked as we are to the sun, it is na Ulti-tural to ask the question, Will the sun last for ever. or will he also die out? There is no apparent res son why the sun should form an exception to the fate of all fires, the only difference being one of size and time. It is larger and hotter, and will last longer than the lamp of an hour, but it is nevertheless a lamp. The principle of degradation would appear to hold throughout, and if we regard not mere matter but useful energy, we are driven to contemplate the death of the universe. Who would live for ever even if he had the elixir of life? or who would purchase, if he might, the dreary privi lege to preside at the end of all things-to be "twins in death" with the sun, and to fill up in his own experience the melancholy dream of the poet, In fact, food is to the animal what fuel is to the the energy of our frames to the food which we eat, In answering this question, let us endeavour to We thus perceive that the action which takes place in a leaf is the very reverse of that which takes place in an ordinary fire. In a fire, we burn carbon, and make it unite with oxygen in order to form carbonic acid, and in so doing we change the energy of position derived from the separation of two substances having so great an attraction for each other as oxygen and carbon, into the energy of heat. In a leaf, on the other hand, these two strongly attractive substances are forced asunder, the powerful agent which accomplishes this being the sun's rays, so that it is the energy of these rays which is transformed into the potential energy or energy of position represented by the chemical separation of this oxygen and carbon. The carbon, or rather the woody fibre into which the carbon enters, is thus a source of potential energy, and when made to combine again with oxygen, either by The sun's eye had a sickly glare Some died in war, the iron brands NEW ELECTRO-TYPOGRAPHIC MACHINE HE Academy gives the following inter Taccount of the new electro-typogr machine : "The French have been more speedy than o selves in putting into operation the modern & ventions in telegraphy. Hughe's American machi which delivers the message in long printed str like a tailor's measure, is employed on all the gre railway lines in France; and the delicate appants of M. Meyer, which faithfully transmits autographs. drawings, Oriental characters, or whatever sender may fancy to trace on the metallic paper, now used on the Lyons railway. "A new electro-typographic machine, the invention of M. Henri Fontaine, a French barrister, is now a work in one of the public offices in Paris. The obje of this machine is to print off with economy and rapidity the quantity of short papers required r law courts, public and private offices, or commeren houses, now executed by the longer and more ex pensive processes of printing or authography. The machine of M. Fontaine, like the electric telegraph. is on the principle of substituting fixed for movabl types, one type only being employed for the same letter; thus dispensing with the ponderau and bulky movable types of the printer. Stev types, representing the different characters used in printing (capitals, small letters, italics, &c.), are ranged around two horizontal dises, placed one over the other. Above these is another metallic circle divided into notches corresponding with the type below. By a very simple machine, as the handle or bar in the centre presses against the notch representing the letter required, an electric shock lowers the type upon a sheet of paper rolled around a cylinder placed beneath, prints the letter, and again returns to its place. The operation is se rapidly performed that a hundred letters may be easily printed in a minute. When completed, the paper is transferred to the lithographic stone to be worked off. The great recommendation of M. Fontaine's machine is its great simplicity, the ease and rapidity with which it is worked, its convenient size (about 3ft. by 2ft.), and its moderate cost. The typography is remarkably clear and distinct, from the employment of finely engraved steel types." ON THE USE OF PHOSPHATES IN DYEING. R. COLLAS, of Paris, has recently succeeded MRCL phosphates as a mordant in dyeing and calico printing. To this end, he passes the yarn or the cloth through a weak solution of a phosphate in an acid, and afterwards though a dye bath or an alkaline bath, by means of which the phosphate is fixed upon the fibre; the stuff, after being prepared in this manner, is ready to be dyed or printed with aniline, or with vegetable, or animal colours. The stuff thus prepared may be passed through a solution of tannin before being printed or dyed. Thus, for instance, in order to dye in dark colours, the yarn or cloth is immersed in a warm and clear decoction of one kilogramme of sumac in four and a half litres of water, of from 30° to 40° C., after which, the stuff is wrung out. It is then immersed for twenty or thirty minutes in an acid solution of phosphate of lime of 50° Baumé, and when wrung out and washed it is ready to be dyed. Purple, especially, yields fine hues. In of the border, and to record every appearance of upheaval, depression, separation in the nature of faults, fissures, or cracks, and to determine the order of sequence of the phenomena thus brought to light as illustrative of the past history of the formation. "4. To examine at intervals of 59, 443, and 1,447 days respectively the objects the appearance of which have been previously recorded, and to keep a record of these examinations with a view to illustrate the present history of the formation. 5. To transmit a record of all observations, whether in accordance with the above suggestions or otherwise, to a central point for examination and discussion. The possible instances of change alluded to under the heads of form and obliteration may occur suddenly, but a physical variation of brightness may be gradual. Two methods may be suggested by which such changes may be detected:-first, a very careful series of observations of spots suspected of change, such as Plato, the observations being continued over a long period; second, a systematic registration of the brightness of spots whenever they are observed. The same remarks apply to variation of colour or tint. It is in this direction that a persevering course of observation and study such observations, and the consequent determi nation of brightness and colour be preserved, they become exceedingly valuable for comparison with later observations." Mr. Anderson says, it seemed an impossibility that it could walk on such soft sinking ground, but on it rushed through all, over some quicksands, ran into the sea and along its edge in every direction in the most wonderful manner. It then, after returning from the seaside, removed an old boiler from the docks to a yard at some distance. The boiler and waggon with the fastening chains weighed upwards of twenty-two tous, and the boiler waggon stood some 25ft. high. Up to this the engine backed, then marched off with its load along the quay, over a rising swing bridge, and along other quays, nutil it reached its destination. The charm of the performance, Mr. Anderson remarks, was the way in which it was done. No shouting, no refractory or desultory pulling of horses, but by the expenditure of a few pounds of coals and water the whole was accomplished with ease and celerity: and so accustomed are the people in Leith to its performance that no notice was taken of it except by the country horses, for the town horses seem to know that it is their friend rather than their enemy. THE MITRAILLEUR AT SHOEBURYNESS. HE mitrailleur which has been selected for trial order to dye with insoluble colours, the cloth is im- may meet with marked success; and if registers of by the English Government is an improvement mersed in a mixture of gelatinous phosphate of lime with a solution of gelatine in water, having a temperature of 25° or 30° C. Cochineal-lake may be prepared in this manner by stirring gelatinous phosphate of lime-hydrate into a filtered decoction of cochineal. M. Alfraise, according to the Moniteur Scientifique, believes this gelatinous phosphate to be of great importance. He thinks that it may replace the cream of tartar, because it becomes insoluble at 100 C., or that, perhaps, in some instances, it may prove a substitute for albumen, especially for cheap goods. For the preparation of dye-lakes, this substance is also worthy of notice as it furnishes many decoctions of dye-woods and lake, different from the alumina-lake. It also affords very fine blue lakes with the oxides of copper and cobalt. Cochineal carmine may also, perhaps, be prepared by mixing a solution of the gelatinous phosphate with a solution of cochineal. have LUNAR ACTIVITY. WE tract, been favoured with the following exsurface, from the letter-press accompanying the portion of the lunar map about to be issued by W. R. Birt to the subscribers. AT THOMSON'S ROAD STEAMER. T the present moment, when so much anxiety has been expressed on account of the exportation of horses, a Parliamentary paper just issued will be read with interest, as showing that the time approaches when we shall no longer require the services of that noble animal. It appears, by the reports on Thomson's "road steamer," made to the War Department, that this engine, unless, perhaps, for hunting purposes, is far more useful than any horse. Mr. Anderson, the Superintendent of Machinery, says he has "come to the conclusion that the question of steam traction on common roads is now completely solved;" that the application of the india-rubber tire is a perfect success; that it opens up an entirely new field, and that he looks upon this application as a discovery rather than an invention he wheel and its very rather than an inven consisting of a broad iron tire with narrow flanges, upon which is placed a ring of soft vulcanized indiarubber; this ring is about 12in. in width and 5in. and is kept in its place by the flanges; then over in thickness, which thus surrounds the iron tire, the india-rubber there is placed an endless chain of steel plates, which is the portion of the wheel that comes into actual contact with the rough road, the vertebra at each side of the wheel. The india-rubber reticulated chain being connected by a sort of tire and this ring of steel plates have no rigid connection, but are at perfect liberty to move round as without the concurrence of the inner ring of the they please without consulting each other, or even wheel which they both enclose. Mr. Anderson states that the reason why this wheel is so efficient is because the soft india-rubber allows it to flatten upon the road, whether rough or smooth. The wheel being a circle, if it is a rigid structure, pre "CHANGE.-The subject of physical change on the moon's surface is one of considerable interest, and continues to receive from observers an increased degree of attention which is calculated to elucidate many intricate points. In the Report of the British Association, 1868, p. 30, the necessity of deteraining the normal character of a spot before any physical change that it had undergone could be ascertained was suggested; this had reference to brightness. In connection with this was a quotation from the Rev. T. W. Webb, relative to certain changes of colour, which he suspected had taken place in the crater Eratosthenes. The reader will find an article on "Scales of Lunar Tints" in the Mure Serenitatis, its Craterology, &c., pp. 13, 14. Darker and lighter surfaces are of importance in the inquiry; for the tint of an object may vary as sents but a small surface, but this wheel conforms seen from the earth in consequence of a physical the veight of the engine causing the india-rubber to every irregularity for a space of nearly 2ft. by change supervening which leaves its form unaltered. to collapse, and so producing a change of form. In The study of physical change may be pursued in the construction of the road steamer the greater connection with the following points, viz. Alteration of form, as when some portion of an object pre- portion of the weight, including the boiler, rests viously well-known has been destroyed; Obliteration upon the driving wheels; the third wheel in front of an object, as a conspicuous crater, for example, is for guiding the direction of movement, and is ceasing to exist as such; Variation of brightness perfectly under control. In the course of experinot connected with changes of visual and illumi- went up a zigzag labyrinth of courts, and it can ments witnessed by Mr. Anderson, the engine nating angles, as when a bright spot at a given place describe any figure almost in a space of twice its is no longer recognizable, and the converse, i.e., length. The boiler employed is an independent ina bright spot appearing where none was seen before: vention adapted to the carriage. Its chief pecuAlteration of colour from darker to lighter, and the liarity is the copper pot for holding water within reverse. It is quite possible that change may be the furnace, and it is so contrived that if the boiler taking place in each of these departments, although contain any water the pot will have a full supply. at present we have no conclusive evidence of the This arrangement keeps the centre of gravity low, fact. In some cases, as regards form, a change may and allows the engine to run up hills of one in ten, occur suddenly, as when a quiescent volcano breaks out into actual eruption, or when a portion of a ring-Anderson saw it in Leith the streets were very wet or along an angle of 35°. On the first day Mr. mountain gives way and a land-slip is the result. To detect such changes, as well as instances of and adhesive. A train of waggons containing ten obliteratim, a very extensive acquaintance with the tons of flour, besides their own weight, were standminutiae of lunar detail is indispensable, and to assisting at the bottom of a slippery street with a gradient of about 1 in 17; to this train the little in the inquiry the following suggestions are engine was attached, and away it marched as if it "1. To examine every part of an enclosed surface, had no load, went up to the top of the hill, and for example, in order to detect the existence of then down on the other side, no brakes being recraterlets, spots, streaks, or other signs indicative Leith it ran down to the Portobello seashore at the quired. After depositing its load somewhere in of volcanic and seismotic (or earthquake) action. 2. To survey by alignment, and also by micro-rate of ten miles an hour. On surveying the sands, metrical measurement, the interior and border of the surface under examination in order to make a drawing to scale of sufficient size to insert on it every object detected. offered : 3. To observe under every variation of illuminating and visual angles the interior and exterior These and their multiples are periods of "similar phase" when the terminator lies near the same spots, the position of the terminator varies with regard to the spots in accordance with variations of the luni-solar Report Brit. Assoc., 1868, p. 9. seasons dependent upon the value of -.-See by Major Fosbery, V.C., on the Belgian model. Its first trial took place on Thursday week at Shoeburyness, and we extract from the Times the following report of the results:-Major Fosbery adopted the Metford barrel and bullet and the Boxer cartridge. The former have been superseded by the Henry rifling and projectile. The Boxer compound cartridge, though excellent for small arms, was proved yesterday to be not so fit for these machine guns as the American form of cartridge made from one picce of metal. There can be no doubt that the Fosbery mitrailleur, as it ought to be called, is superior in all respects to the Belgian arm, but it is equally certain that the experience of English experimentalists can suggest further improvements which can certainly be carried out by English mechanists. As usual we are late in adopting a new weapon, but, having adopted it, we shall carry it out to greater perfection than has been done by any foreign nation. We have often expressed our opinion regarding it. We believe that it will hold a worthy place in battles and sieges, and that place is between the fire of infantry and field artillery. The experiments have confirmed us in that opinion, but it would be unwise to sit down and dogmatize after one day's trial. It is better to await further proof blished. So far as we can see, it may be very imbefore actually declaring its value as a thing estaportant if attached to cavalry, especially to break squares, to tear lines to pieces, and to harass a retreating enemy. In fortresses it must be of great It gives the fire of perhaps a dozen infantry soldiers armed with the best known weapons. use.. Mounted infantry, "dragoons," in short, would perhaps do as well, but it is impossible to prevent mitrailleur is extremely light, eats nothing, and its their changing themselves into cavalry. The use can be easily learnt by artillerymen. It has no nerves to unsteady its aim, and if lost cannot be used by an enemy unless he has the same small arm ammunition, which ought always to be that of the infantry rifle in use. With these few words of preface we will simply committee appointed to try it. relate the experiments carried out yesterday by the The first discharge was from the mitrailleur, at a range of 800 yards-too far for anything like steady shooting from infantry in battle. All preparations having been made, and the telegraph having been duly worked to ensure safety to everybody concerned, the small detachment assembled round the piece. An officer stood with a timekeeper in his hand, and when the hand came round to an easily marked place on the dial, cried "Load!" Instantly the axletree boxes, close on each side of the barrels, were opened, and a breech-plate with its 37 cartridges was seized quickly and placed in the hollow breech while the laying of the piece was in progress. One momentary pressure on the lever pushed up the plate and its cartridges to their place and cocked all the locks; then the word “Fire was given by Captain Alderthroughout the trials; a gunner beside the piece son, who superintended the working of the machine pressed rapidly down the side lever, and in an instant the locks were set free and 37 bullets sent flying through the air. The sound was exactly like that of a volley of musketry, but the target was too distant to allow of hearing the sharp taps of the bullets upon its wooden face, so different from the dull thud made when a small missile finds its rest in human than an upward thrust of the lever freed the breechflesh. No sooner was the crash of the volley heard plate again and left it loose, to be instantly lifted out by the gunner on the right of the piece. The same process was repeated a second and a third time without a hitch, and very rapidly, but when the fourth breech-plate was about to be inserted it became manifest that the whole of the cartridges could not enter their barrels, because two out of the 37 last discharged had adhered too tightly -a to their barrels, so tightly that their bases had been would very likely have killed two, and during this It is clear that fresh cartridges could not be forced in, and an inexperienced hand would have taken it for granted that the mitrailleuse must cease firing, but not so Captain Alderson. Quick as lightning, his eye detected the blocked barrels, and, with hardly less speed, he seized the bases of the two cartridges corresponding with them, and about to be introduced. They were rapidly extracted, and then the breech-plate was dropped into its place, pushed home by the lever, and fired as before, but only 35 bullets this time left the barrels. The fifth round was fired like the fourth, two cartridges being extracted as before, but the fifth breech-plate left behind it two more cartridge cases, blocking two additional barrels, so that this time four cartridges had to be extracted. These mishaps, which were solely due to the compound form of the cartridge case, caused a certain amount of delay, and the two minutes expired before a seventh round could be fired. | It is not necessary to say how great was the interest, nor how anxious were all present to rush to the target and see the results. No one would have grudged the run of 800 yards, but means of transport were at hand in the shape of a truck or lorry, drawn by a horse and running along a railway laid down along the range. It was soon crowded and even heaped up by a mass of gentlemen, all eager to see for themselves what had happened. As they neared the long black target the range party were seen spread all along its face busily counting the bullet holes and marking them with daubs of white paint lest they should be counted in favour of another discharge. The total number of bullets fired ought to have been 222, but eight cartridges had been withdrawn because of the blocked barrels. There remained, therefore, to be accounted for 214 bullets. No slight hits such as could be made by missiles rebounding from the earth, but there were found 110 fair hard strokes upon the target. They were to be counted as through" or lodged." So far as we could see, they were all through. Some of them had not actually struck the painted figures, but were to be found perhaps within an inch, or even closer, of the men's heads or the horses' legs. Now a rear rank, whether of cavalry or infantry, never covers its front rank so accurately that bullets missing their comrades in front must fail to strike them also. Again, in some cases more than two bullets had lodged in the same man or horse. Targets cannot be made to represent accurately the effect of artillery or infantry fire upon flesh and blood by any method of appropriating the value of the bits. Yet it does seem a little too much under the mark to set down that the 110 bullet holes in the target would only have placed hors de combat 38 cavalry or 45 infantry. All that can be said is that, generally speaking, in a competitive trial of this sort the same method of marking is equally fair to each of the rival weapons. That it would be so in this first round we have no doubt, because all the barrels were fired so nearly at the same moment during each discharge that the stricken soldiers would have no time to fall, or at least that their places could not have been supplied by others in time to catch the next bullets on the same spot. But this is not the manner in which the mitrailleur is intended to be fired against lines of horse or foot. On the left of the carriage, just below the breech of the weapon, is a small wheel with a handle, which, being turned, gives a horizontal motion to the piece, and we have more than once explained that the thirty-seven cartridges of the mitrailleur can be fired either all at once, as in this first series, or one after another at whatever speed may be required. In all future firing throughout the day the latter method was adopted, and the horizontal motion given. Thus is disposed of that most curious of objections that the mitrailleur shoots too well, and throws its bullets too closely together. And how great an advantage would this close volley of bullets be in cases where a bridge or a road, or a narrow pass, is to be defended! has not been stirred by that episode of the battle of Who Meeanee, when Sir Charles Napier placed a small group of infantry soldiers in the gap of a wall, and told them that they might die there, but that the enemy must not enter it. They did die there nearly all of them, but they kept the pass. Two or three mitrailleurs would have done it better, and with no loss of life. When the officials and visitors had feasted their eyes sufficiently on the targets and marked how one man must have been shot in the heart, another in the head, and another in a limb only, the lorry was put in requisition again, and a group once more assembled round the initrailleur. Two minutes were again given as the limit of time, but now the discharges resembled file firing, the horizontal motion being given so as to distribute the bullets. The Metford bullet is hard and heavy, and there can be no doubt that it will pass through one man and kill another behind him; many of the hits, therefore, that were counted as only disposing of one soldier and many of those that were not counted at all It was now the turn of the field guns, and the new 9-pounder Indian bronze gun was placed in position. Let it not be for a moment supposed that the mitrailleur can be set up as a rival to rifled field artillery for general service. Where the power of the mitrailleur ceases that of the rifled field piece may be said to be in its highest perfection. If, therefore, at the short ranges of to-day the new weapon appears to advantage, further experiments will show that the limit of its powers will soon be reached, and no wonder. The 9-pounder Indian field gun weighs 8 cwt. The mitrailleur only 3 cwt. and 20lb. The 9-pounder, with its carriage and ammunition carried with the gun, but without waggon, weighs 334 cwt., and requires six horses. The mitrailleur, mounted on a carriage suitable to it, with lumber and ammunition complete, would weigh 12 cwt., and could be drawn by two horses. So that weight for weight and horses for horses, three mitrailleurs could be taken into the field for one 9-pounder rifled bronze gun. The mitrailleur requires but one non-commissioned officer and five men to work it luxuriously, and three men could manage it comfortably at a pinch. The 9-pounder requires a non-commissioned officer and ten men, yet the practice of yesterday seems to show that there are occasions when, within certain definite limits, the mitrailleur may even surpass the 9-pounder gun. At the range of 800 yards firing shrapnel with time fuzes the 9-pounder muzzle-loading gun was fired five times in its first two minutes, and eight times in its second two minutes. The first time it, like the mitrailleur, had its mishaps in loading. Its effect was 118 hits on the target, counted as 24 cavalry or 27 infantry killed or disabled. The eight rounds fired in the second two minutes gave 115 hits and 45 cavalry or 51 infantry placed hors de combat. Next was brought up the 12-pounder breechloading rifled field gun of the service. Segment shells were fired from it with concussion fuzes. Six times in two minutes did it send forth a projectile intended to burst and envelope the target in a shower of iron fragments. At the end of its firing the account given was-hits 38, cavalry disabled 15, or 18 infantry. The same gun was then fired with shrapnel carrying time fuzes. The result was even less, 15 hits, eight cavalry or five infantry killed or disabled. This closed the practice at 800 yards. The mitrailleur was brought up 200 yards nearer the target. At a range of 600 yards it fired six rounds and gave 127 hits, killing or wounding, often with several bullets, 61 cavalry or 51 infantry. But now it was in its turn surpassed by the muzzleloading rifled bronze gun, firing shrapnel, with time fuzes, for at 600 yards it was fired seven times in two minutes, and gave 283 hits. Its slaughter was counted at 68 cavalry or 88 infantry. The ninth group of rounds was from the 12. pounder breechloader, with shrapnel and time fuzes, at 600 yards. Result-142 hits; 48 cavalry or 58 infantry disabled. The time required for numbering all the hits upon the target, and calculating men and horses killed, had so delayed the firing that by this time it was late in the afternoon, and there was only time for two more groups of shots. The mitrailleur was quickly brought up to within 300 yards of the target. Only five rounds were fired from it in its and, by the calculation of the committee, would two minutes, 171 bullets penetrated the target, have killed 60 cavalry and 129 infantry soldiers. BLOOD PICTURES.-Dr. Day, of Geelong, Australia, the improver of the guaiacum-tests for blood and other animal fluids, confirms the discovery of Neumann, that the picture or network formed by human blood can be distinguished under the microscope from that which is formed by the blood of other animals. He says he has repeated the experiment, which is wonderfully simple," almost every day for the last two months with invari able success. A small drop, not a mere speck, of blood, is to be placed on a microscope slide, and carefully watched, at a temperature of 10 or 12 Reaumer (= 54-2° to 59 Fahr.), until the picture or network formed by its coagulation is developed. Human blood speedily breaks np into a "small pattern" network; the blood of other animals (calves, pigs, &c.) takes a longer time, and makes a larger pattern; but the blood of every animal seems to form a characteristic "picture." Dr. Day, has examined the blood of calves, pigs, sheep rabbits, ducks, hens, several kinds of fishes, &c., as well as that of man, and has found the results to be trustworthy and constant. MICROSCOPICAL NOTES. A SIMPLE AIR-SIEVE.-The apparatus maluse of consists of a small deal box, about 12in. squar having an opening to the front with sloping side so as to direct the current of air directly upon the surface of a glass plate, which slopes (at an angl about 22) from a vessel containing distilled wat at the upper part of the box, to a trough placed its base. The water is caused to trickle slowly re the glass plate by means of a cloth siphon from 5 upper vessel. In its course it comes in coule with the air, which is conveyed in a current threag an open window into a room whose temperature greater than that of the outer air, thus caual traversing of the air of " out-o'-doors" to the chamber. The box contains a smaller open. the chamber, through which the current can lea tected. The water which trickles over the p then collected in the trough at the bottom, v when examined microscopically, shows the p of Monas Lens upon its surface, and when tes solutions of potassic permanganate, by me volumetric analysis burette, shows varying One tions of organic matter present. fact is that the presence of monads is al these experiments, best discovered by exthe surface of the liquid. By the use of wate in the apparatus described, the particles float the air are seized in a way which produces no in and the surface brought into contact with the larger than in Prof. Angus Smith and Dancer's " periments.-Monthly Microscopical Journal. NEW MODE OF SUB-STAGE ILLUMINA TION.-Dr. J. Matthews has devised a plan for the purpose which has been very favourably spoken of It consists in the employment of a low-power objectglass, so fitted that the pencils proceeding from it may be thrown at any angle on the object. Dr. Matthews has solved the difficulty of sub-stage illumination by adopting one of the objectives themselves, of lower power, as an illuminator in place of a condenser, but not axially. It must be so mounted as to send the whole of its bundle of 25 to 65. ACTION OF LIGHT ON FERTILE FROG'S OVA.-Herr Auerbach recently contrib to certain numbers of the "Centralblatt" the resti of his observations. He states that during t spring (April 13th to 20th) of the present year b had frequent opportunities of observing the sp circumstance that even the diffused light of day. of the frog, and was particularly struck by the but especially the direct light of the sun, const tuted a powerful excitant of the contractions of the protoplasm of the egg. If the amount of light falling upon an egg, or, more correctly speaking on the primary segmentation spheres and the secondary results of fission, be increased, of form may be seen to occur even under the eye of the observer. If the egg be so placed th the white pole is directed towards the light, the contractions excited have a tendency to push the black pigment in part over the white area, or ever has been completed, this pigmentation of the clear to completely cover it, whilst the opposite pole be comes whiter. When the first meridianal furrow alterations area occurs to a less extent. This alteration in the distribution of the pigment must not be confounded with the well-known rotation of the yelk, which de pends on the centre of gravity being near the white pole. HOW TO PREPARE YOUNG OYSTERS FOR THE MICROSCOPE.-Having found a "blacksick" oyster (to use the dredgermen's term), the spawn of which is quite mature and ready for extrusion, pour off from the shell the dark slatecoloured fluid into a long narrow two-ounce phial; fill up the bottle with distilled water; shake it up gently; allow the deposit to settle, and change the water two or three times, repeating the agitation to get rid of the salt. Then substitute for the water liquor potasse, diluted with an equal quantity of distilled water. Allow the young oysters to remain in this for two days, agitating occasionally; and, as often as the solution becomes discoloured, pour it off, and renew the same until no colour is given off and the shells are seen to be thoroughly cleansed from all animal matter, by their sinking freely and rapidly to the bottom. When this stage is arrived at, stop the process, that the two valves of the shells may not be separated by the destruction of the hinge. Wash repeatedly in distilled water, to remove all trace of the alkali, and finally wash and preserve the shells in a little rectified spirit of wine (not methylated spirit). When they are to be mounted for the microscope, shake them up with the small quantity of spirit; and, before they settle, dip in a fine camel-hair brush, and deposit its contents on the slide. If too much spirit has not been added to them, there will be just enough of the shells in the brush to make a nice object. They show better when not huddled together too thickly. If undistilled water or methylated spirit be used, instead of being brilliant and clean, the shells will probably have the milky and semi-opaque appearance which is so objectionable. As each oyster produces on an average 800,000 young ones, the spawn of one parent will be sufficient for almost any number of slides. It is worthy of notice that, in its early condition, the oyster has both valves equally convex. This process is equally applicable to the bleaching and preparation of starfishes.-Science Gossip. WASHING CHALK FORAMINIFERA.-Take about one ounce of chalk-that which lies in powder at the base of a chalk cutting is preferable, place it in a quart bottle with about a pint of water, shake it, and after a few moments pour off the milky fluid down to about one-fourth; add more fresh water and continue the shaking and pouring off, waiting longer each time for the debris to settle. If this washing is continued through ten or twelve times in one day, and afterwards repeated two or three times a day for a day or two, the final result will be a sediment entirely composed of Foraminifera. By this means nothing can be detected as mixed with the Foraminifera. If small fragments of chalk remain mixed with the Foraminifera, that will give evidence of insufficient shaking. Plenty of water and plenty of shaking is sure to produce satisfactory results.-Science Gossip. CIRCULATION OF THE LATEX IN THE LATICIFEROUS VESSELS.-Some experiments have recently been made upon the circulation of the latex in the laticiferous vessels of the leaf of Chelidonium majus. According to some authorities there is no visible motion except such as is the result of injury, while Schleider says," that in the uninjured vessels, the motion of the latex can very seldom be successfully shown." Now by potting a young plant of Chelidonium majus, and placing any one of the young leaves between two strips of glass (upon which a drop of glycerine has been put), in such a manner as to bring the under side of the leaf upper most on the stage of the microscope, so as to throw the strong-reflected sunlight upon it from the mirror below, it appears that-1st, there is occasionally either a nearly total want of motion, or only a slow one, of the coloured granules, or at times a very rapid motion of the particles to be seen; 2nd, that while watching the circulation as seen through the lenses, if the diaphragm be moved from left to right, so as to cause the shadow to enter upon the right of the field of view, a brisk circulation is instantly witnessed, which appears to be changed in direction as the diaphragm is moved back again, so that the direction of the circulation can be changed at will by the interception of the sunlight. The same result is seen when clouds pass between the sun and the mirror. The direction of the circulation is from the apex of the leaf in sunlight, and towards it in the shade. Prof. Balfour says, that in plants with milky and coloured juices evident movements have been perceived, and mentions the calyx leaves of Chelidonium majus, as also the india-rubber plant, the guttapercha tree, and the Euphorbia, as examples. The Leontodon taraxacum also exhibits a similar phenomenon. SCIENTIFIC SOCIETIES. NORWICH GEOLOGICAL SOCIETY. curred with Mr. Taylor, and mentioned a fact he had FRICTION.-X. BY C. DRAPER, A.B., L.C.E. If one body roll on another the resistance is very = = = = The great advantage therefore of wheels applied to carriages of all kinds arises from the friction being transferred to the axle, and being then reduced in the proportion of the diameter of the wheel to that of the axle; hence, the larger the wheel and the smaller the axle the less work is lost in overcoming friction. Considerations of a practical nature of course set limits to the sizes of wheels and axles. Thus, if the axle be very small it will also be very weak, and if the wheel be very high the level of the axle will be above that of the point of attachment of the traces to the horse, etc., and therefore a portion of the effort of the horse will be lost in urging the wheel against the ground. An extension of the same principle explains the advantage of "friction wheels " and "friction rollers." When these are employed, the journal of a shaft, instead of turning in a pedestal, as is usually the case, rolls on the circumference of a wheel or roller, as in Fig. 24. Frequently each end of the shaft is supported by two rollers, as in Fig. 25. Let & be the diameter of the journal A, which supports a weight W; D the diameter of the friction roller B; and d the diameter of its axis C, which turns in a cylindrical bearing. Suppose now that A were turning in a bearing like C, with the same coefficient of friction, then the work which would be expended on A in one revolution would be μ W xd, when it is supported on the roller B; however, when it has made one revolution, B, and therefore C, has made a fraction of a revolution AT T the monthly meeting of this society, held on the 8 2nd inst., at the museum, Mr. J. King in the represented by, supposing the motion of A and B to chair, numerous specimens of the bones of Elephas and be that of pure rolling; the work expended in friction Bos primigenius, were exhibited by the Rev. J. Crompton, having been picked up by him during a recent stroll on in this case is therefore only μ W × ×d, neglect the coast near Bacton. An interesting discussion took place on the origin of the stony bed lying between the ing the weight of the friction rollers. The work lost in crag and the chalk. Mr. J. E. Taylor stated the the former case bears therefore to that lost in the hypothesis that from the secondary period to the latter the proportion of μ Wx:π W×D× Glacial-epoch Norfolk was a land surface, and that the chalk had been gradually worn away by pluvial and that is of D to d, or the diameter of the wheel B to atmospheric action, so as to leave the flints, which are that of its axis C. naturally distributed through the chalk, in a mass, thus forming the stony bed. The finding of the bones of Hipparion, or three-toed horse, in this stony bed tended to show that there was a land surface. The finding of an enormous flint embedded naturally in the chalk, and a portion of it exposed in an upward direction, showed that the chalk had been worn away by the agencies he had mentioned. Mr. Bayfield con δ πd, When there are two rollers under each journal, as in Fig. 25, the only difference is that the load on the journal A is equally divided between the two rollers B B', the friction on each akis C C' is consequently halved; but as there are two of them, the total amount remains the same. If we support the axes of the friction rollers again on other rollers we shall still further diminish the friction, although at the same time in creasing the weight on the last axis. Practical considerations such as this, set limits to the reduction of the friction; thus we might reduce it to any extent by increasing D or reducing d in the same proportion; but if D be very great, the weight on C will also be very great; and if d be very small C will be very weak. THE ANTI-FRICTION CAM-PRESS.-The name of this press is derived from its peculiarity of having nearly all its motions rolling motions. Now, although this reduces the friction to a minimum, we must not lose sight of the fact that without friction we could have no rolling motion whatever; for if friction did not exist, the application of the slightest force would cause one body to slide on another, provided, of course, the direction of the force was other than normal to the surface of contact. of two cams C C', of spiral form, turning respectively on the axles A A'. These axles again roll on the sectors S S', the apices of which turn on knife edges K K bearing against the foot and top of the press, K being fixed and K' movable upwards and downwards in a vertical line. Between the cams is a roller, R, which is turned by a winch either directly or by the intervention of toothed gearing. The mode of action of this press is perhaps best understood by reference to Fig. 28, which represents the frame of the press, the cams and sectors being shown behind. Fig. 26 shows the initial, and Fig. 27 the final position, when K' is at the extremity of its travel. By referring to Fig. 26, it will be seen that as we turn the roller R in the direction of the arrow, the cams will revolve in the directions shown by the arrows next them; so that in the final position, the roller R will have itself been raised a height equal to the difference of Aa and Ab; that is, the excentricity of the cam C. In like manner, if the peripheries of the cams be the same, the cam C' will be raised to a height relatively to R, equal to the difference of A'a' and A'b'; therefore the total travel of K' will be equal to the sum of the excentricities of C and C'. In Fig. 28 it will be seen that the frame F is attached to the vertical columns P P', so that when the press is worked, the columns rise upwards, independently of the frame, carrying with them the follower H, thus compressing the substance D between the fixed piece K and H. To calculate the efficacy of this powerful machine, let us assume the following dimen sions: EXAMPLE 20.-Let the length of the periphery of the cam C or C' be 3ft. 4 in., the diameter of the roller R be 24in., the excentricity of each cam be 2in., and let the winch give motion to R by means of a wheel and pinion having respectively 52 and 8 teeth. Let the diameter of the circle described by the winch be 2ft. 7 in., and let it be turned by two men exerting each a force of 201b. Find the force with which a substance will be compressed by the machine, neglecting the small amount of friction which exists. Here the resistance is urged through a space of 4in. We must then find the length of the path described by the power of 40lb., while the follower makes its travel of 4in. Now, by measurement, it is found 38.7 7 x 2.5 38.7 52 that 19-20ths of the periphery of the cam is passed over 38.7 P x 4 7 x 2.5 х must be the num 8169.5 x 40 applied must be equal to have 12 = contains water, a yet heavier fluid than compressed air, not to mention the water tank and its contents, with coke or coal to boot. So a compressed aircarriage may not be quite so absurd a thing as it has been pronounced to be, and a compressed air velocipede will certainly soon be un fait accompli-that is, as can import and naturalize from the green" isle (not its similarly coloured natives-they are imported in quite sufficient numbers already) certain natives' "green ideas," especially that which had the honour of being figured in the ENGLISH MECHANIC some months ago: I mean the celebrated fly-wheel velocipede which ascended (?) hills easily in Consequence of the heavy fly-wheel with which it was provided. Having achieved this Hibernian reversal of dynamical laws, it follows that we may do without springs altogether, for we have only to make the dy wheel large enough and heavy enough to compel it to take up hill the carriage, the air vessel, if we yet prefer carrying one, and the heavy-sterned Christian rider together; but being, in the matter of mechanical contrivance-if not in the employment of language an advocate for using the fewest possible parts (I do not mean parts of speech), I would humbly suggest that the principle might be carried out in a less complex form by removing the boiler-I mean the airvessel-and also the carriage, and suspending the Christian from the axle of the fly-wheel. Should this be found in practice to put this unique one-wheeled velocipede out of balance (which might be the case if all mechanical laws were not treated like the Christian, re-suspended), that balance might be restored by All communications should be addressed to the suspending another Christian of similar conformation on the opposite side. May I further suggest that our Chancellor of the Exchequer and Chief Commissioner of Public Works be selected for the first experiment ? for should anything unpleasant occur, the spectators employment of objectionable words, because the two gentlemen I have proposed are both so remarkable for dignified courtesy and polite speech. LETTERS TO THE EDITOR. [We do not hold ourselves responsible for the opinions EDITOR of the ENGLISH MECHANIC, 31, Tavistockstreet, Covent Garden, W.C. All Cheques and Post Office Orders to be made pay- could not possibly have their feelings shocked by their able to J. PASSMORE EDWARDS. "I would have every one write what he knows, and as much as he knows, but no more; and that not in this only, but in all other subjects: For such a person may have some particular knowledge and experience of the nature of such a person or such a fountain, that as to other things, knows no more than what everybody does, and yet to keep a clutter with this little pittance of his, will undertake to write the whole body of physicks: a vice from whence great inconveniences derive their original.”—Montaigne's Essays. One fallacy which has exhibited great vitality in the pages of the ENGLISH MECHANIC is the proposal to propel velocipedes by coiled or other springs, which, in the language of a reverend correspondent (by the way, reverends can hardly be expected to be familiar with such merely mundane things as coiled springs), you may "wind up" just as you do your watch. May I suggest that, although an analogous operation, it is no more "just" as you wind your watch than is the winding of the church turret clock, whose maintaining weights are from a quarter to half a ton? Doubtless both are treated like a limited liability company, and "wound up; " but I think if reverend fellow-correspondent was accustomed to that peculiar kind of "church service" yclept turret clock winding, he would hardly have treated velocipede spring winding so lightly as to say "just like you wind your watch;" on the contrary, the injunction to "watch and pray" must have been involuntarily carried out by him, for he would most certainly have watched anxiously for the reappearance of the heavy maintaining weight and prayed fervently to be relieved from the labour. my This not very new subject has cropped up repeatedly in the pages of the ENGLISH MECHANIC, and even before that journal came into existence, for perhaps forty years. Certainly it was not invariably "just as you wind up your watch," for an engineer whose experience was probably greater (even if his faith in the art of removing mountains with small expenditure of muscular energy was less) than that of your clerical correspondent long ago proposed to propel carriages, from railway locomotives to velocipedes, by compressed air, which is, however inconvenient, rather more practical than employing coiled steel springs. It would require iron air-holders like the gas-holders of the long-since defunct portable gas company, or, perhaps, something resembling an egg-ended steam boiler. Perhaps, however, they would not weigh much more than the steel spring, or rather, the scores of steel springs which would be required. In both cases, a person so utterly ignorant of the laws of dynamics as a mere blacksmith must necessarily be might very unreasonably object that all this additional weight had to be carried on the wheels of the carriage and lifted up the inclines, which certainly requires force to effect (at least in England). After all, the same may just as traly be said of the boiler of the locomotive, which Not having a very lively faith in the immediate tion. sions of a spring would be that would take himsy The only thing about the matter which seas feasible is, as I have before said, to store apa the force of gravity which runs to waste was down hill, instead of absorbing and cansing. changed into heat by the brake. This is no dese desirable, but not very easy to do without adiy siderably to the weight and greatly increasing of a velocipede; but, perhaps, I ought to say t about its cost; for when we want not only to na also to construct our hobbies, fifty or one ha pounds worth of springs is of course no considerse whatever to ye English mechanic, who is invar such a go-ahead fellow, and proceeds so utterly gardless of expense. For myself, being, in the phys sense, a very broad churchman, i.., a heavy Christic I prefer walking on my own feet to "valking c. veels"-riding in a carriage propelled either by stear or horses. I do feel it would be great presumption is me, at my time of life, being a mere biped, to attempt to compete with that noble quadruped the horse. sutor, &c. Instead of feeling that I had the inestimable privilege of being gifted with reason, I should esteem myself no wiser or better than Plato's man, who, if not a goose, doubtless was at least first cousin to a gander (although reported in ancient story to have been a Frenchman-I mean a galinaceous fowl stripped of its feathers); but I think the male goose would have "ansered" better as a representative of humanity. especially as it more nearly approaches to the on nary intellectual condition of mankind, so I infer! must have been either a male goose or a female gander, it little matters which. "Arcades Ambo," quetes Byron-may perpetrate another specimen of canin Latin and say of man and his "placked" representstive, Ansari duos." THE HARMONIOUS BLACKSMITE. [224] SIR,-At the risk of increasing that "deluge" of my correspondence, which according to "Alexandra " has flooded our journal sincs renquiry appeared in No. 260, of March 18th, I feel all to reply to her. I have only had two contributed up to August 5th. The first related almost exauty to improving the treble of the piano, and the chiefly to her own design for an upright instr and in it I stated the honest truth, that I am not abs moniam but a pianoforte maker, and that I do thļu tend to anything like that practical acquaiutano the construction of harmoniums which distingu Mr. Hermann Smith, Mark Ellor, Eleve, &c. that as regards great variety in the power and qua of the sounds of different ranks of reeds, I mere suggestor. Did it never strike " Alexandra," k most significant fact, how little she is indebted t trade for the information she required, through: columns of the ENGLISH MECHANIC? In t I trust that patent will not return evil for good and If "Alexandra" will refer to her letter of enquir specting Myers's reeds (I quote from memory. having the number at the moment before me), she s that my letter bore the peculiar "ring" of another very valued correspondent of the ENGLISH MECHAN alluding, of course, to the "Harmonious Blacksm For this reason, also because he was born with a sily The "Harmonious Blacksmith," whose abundance of utterance is rather apt to overflow, not to say “delage," About a year ago a prudent correspondent enquired- the ENGLISH MECHANIC (I leave him to fight his own it was very prudent in him to do so before" commencing battle with you, Mr. Editor, and her Royal Highness, re to manufacture on the large scale"-what the dimenspecting the insertion of so many of his effusions) ha |