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THE

MECHANICS' MAGAZINE.

LONDON: FRIDAY, JULY 3, 1868.

THE MOLECULAR CONDITION OF

PROF

current.

that the intensity remains the same, then the
full range of the molecular conditions of the
deposited metal could not be obtained. With
these conditions the range could extend only
from amorphous to reguline metal.

motion.

THE SILVER COINAGE OF GREAT but it must be a work of many years, and "whilst the grass is growing the steed is starving."

BRITAIN.

That

tender after December 31, 1868. The banking houses in all the cities and towns of the empire might be constituted receptacles meantime for the condemned money, which would then be readily transferred to the Making the external resistance constant, Mint. In short, there would, by the exercise and commencing with an external resistance of a little judicious management on the part equal to the internal, then the deposit will of the proper authorities, be less inconvenibe reguline and malleable. Now, if, on the ence caused in improving the silver coinage one hand, we gradually increase the quantity, than arose from the remodelling of the copper we shall descend through porous to amor-currency at our instigation a few years since. phous metal; but if, on the other hand, we It may be urged in defence of delay, that a gradually increase the intensity and lessen the commission is now sitting and deliberating ELECTRO-DEPOSITED COPPER. quantity, we shall pass through hard brittle upon the whole subject of the coinage, and ROFESSOR GUTHRIE, in writing reto crystalline metal. So that, at the one end that its report has not yet been made public. specting his voltastat to our chemical of the range, we have copper in amorphous To this we reply that many commissions have contemporary, makes some remarks respect-powder, and, at the other, in crystals. In sat before on the same question without ing the electro-deposition of copper which do this case, the external resistance being con- much advantage finally accruing to the comnot exactly represent the relation between the stant, the molecular condition of the metal is munity from their cogitations. Moreover, be electric current and the molecular condition a function of the power of the battery, and the nature of the expected report what it of the copper deposited, and consequently in every case it is a function of the current in may, the step we propose is one only rememight mislead those who are not thoroughly dial of existing and patent evils and not inconversant with the subject. He says:volving a revolutionary change. That might "The second point raised by the President, follow the deliberations of the commission, who expressed his opinion that the voltastat was not applicable to weak currents, such as are required for the deposition of copper, I INCE the publication of our last article need only remind your readers that the SIN It is too much to expect that a decimal on this question* an important step has tenacity of the copper film is not a mere been taken by the Emperor of the French in system of coinage will be recommended by the function of the power of the battery, but reference to the silver coinage of France. commission, or that it will be adopted by the also of the extent of the surface upon which By a decree of his Majesty, promulgated on Legislature if it be so recommended.. the deposition takes place, and that the the 18th ult., it is ordained that all "old" such a system would be of the greatest poscoveted state of aggregation of the copper is two-franc and one-franc pieces, and all old sible advantage to the whole commercial and attained by extending the receiving surface, fifty and twenty-five-centime picces circu-trading community of the United Kingdom as well as by diminishing the strength of the lating throughout the empire and its depen-is, to our thinking, beyond doubt. A mounis more coherent when the deposition takes the month of October next. This is, in fact, rate it on this side the Channel, and assuredly Cæteris paribus, the deposited film dencies shall cease to be a legal tender after tain of prejudice, however, must be removed before any Ministry will be able to inauguplace more slowly. Given a current of a cer- doing for France precisely what we have tain strength-let the surface to be electro- been strenuously urging the British Govern- none will feel disposed to undertake the Herplated be exceedingly small-the copper de- ment to do for this country. Unfortunately, reform can be instituted the public mind culean task gratuitously. Before this great posited will crumble away as it is formed. Let however, it is exceedingly difficult to accomnow the current remain the same, but let the plish at home what can apparently be effected will have to be educated on the point to a surface be extended; then, in the same time, the by a stroke of the pen abroad. It has been much greater extent than at present. The same amount of copper will be deposited, but clearly shown in our columns that the present minor improvement to which reference has being precipitated upon a larger surface, it will state of the silver coinage of Great Britain is been made is within immediate reach, whilst be thinner: the deposition will have taken place disgraceful in the extreme, and there are few its necessity and usefulness cannot fail to be more slowly, and the copper will be more persons who have not experienced annoyance universally admitted. tenacious." This paragraph does not at all from coming into possession of, and then It has been previously stated in the columns express the law of the electro-deposition of being unable to " pass," worn shillings and of this journal that no crowns, half-crowns, or copper, or of any other metal; besides, it sixpences. It is quite evident to all ob-fourpences have been coined at the Mint for contains a contradiction in the last two senservers that the rate at which new coins, of many years. It is to be. hoped, also, that no tences, beginning with,-"Given a current of these denominations especially, are issued more of either denomination will ever be a certain strength, &c.," and in the last sen- from the Mint is by no means commensurate tence he says, "Let now the current remain with the speed at which they deteriorate and the same, but let the surface be extended; wear out in circulation. The system now then, in the same time, the same amount of practised for renewing the silver currency is, copper will be deposited, &c.;" and, in the indeed, ridiculously inadequate for its purlast clause, he says that "the deposition will pose. A certain sum is included yearly in have taken place more slowly.' But how the Mint estimates voted by the House of can that be, if the same amount of copper be Commons for covering the loss arising from deposited in the same time? Leaving this the purchase of worn coin, and the Bank ancontradiction, we do not agree with Professor nually withdraws from circulation and sends Guthrie that the results will be as he states, to the Mint a certain quantity of it. It contaking the conditions as he assumes them,-sists mainly of half-crowns, shillings, sixFirst, given a certain current, and a certain pences, and fourpences, but the number of surface to receive the deposition, then enlarge the receiving surface, and the amount of copper deposited will be the same in the same time. Now, under these conditions, the amount of copper deposited would not be the same in the same time, but larger in the second instance than the first, and for the following reason: the amount of metal deposited is in all cases proportional to the electro-motive force of the current in action, and this is governed by the size of the plates in the battery, number of elements, and external and internal resistance of circuit. If any of these be varied the result will be varied. Now, in the second instance, the receiving plate being enlarged, the external resistance would be reduced; consequently, a stronger current of electricity would flow, and an increasing quantity of metal would be deposited up to the maximum power of the battery which would be attained when the external and internal resistance of the circuit were equal. Moreover, the molecular condition of the metal deposited is not governed exactly by the conditions the Professor sets forth. Assuming the same conditions, namely,

defective pieces of these denominations in
existence at this moment forms the most
severe commentary upon the homoeopathic ar-
rangement between the Bank and the Mint.

con

struck there again. There are serious objections to their existence in the family circle of British coins. The crown of nearly one ounce weight is far too cumbrous for ordinary use, and resembles a medal rather than an item of the circulating medium. Still greater is the half-crown nuisance. In juxtaposition with the florin it is fruitful of interminable errors. Shopkeepers and others are tinually and with great justice complaining of the mistakes and losses constantly resulting from the intermixture of half-crowns with florins. The public who are not connected with trade are frequently put to inconvenience by the same circumstance, and it is almost universally conceded that either the one or the other denomination of money should cease to exist.

The proper course to pursue is that which we have indicated before, and which the No doubt the half-crown has its friends, French Government has forestalled ours in but they are few and far between. In the taking, namely, the relegating at "one fell House of Lords that rather crotchety nobleswoop "all old silver coins to the melting man, Lord Overstone, has long been an advopots of the national money manufactory, and cate for its continuance, but until Monday supplying their places with new money week we were not aware that the half-crown as speedily as the Mint presses can be possessed a supporter in the House of made to stamp it. The imperial decree Commons. Sir F. Heygate on that occasion for effecting the needed reformation in asked the Chancellor of the Exchequer France does not define what is to be under- whether "that useful coin was ultimately to stood by "old" coins, but, presumably, the word applies to such as have been struck anterior to the reign of Napoleon III., and no doubt explicit instructions will be given in due season. Our own plan for effecting a similar object throughout this country would be the issuing of a Royal proclamation making all silver coins of a date prior to that of the Queen's accession in 1837 a non-legal

* Vide MECHANICS' MAGAZINE, May 22, page 383.

be withdrawn from circulation." In reply, the hon. member was informed that "no new half-crowns had been coined for fifteen years" (we never heard that the Mint ever coined old ones), "that the present supply was adequate to the demand," "that half-crown pieces formed about 30 per cent. of the silver coinage," and that "there was no present intention of withdrawing them from circulation." How Mr. Ward Hunt arrived at the conclusion that half-crowns composed 30 per

cent. of the existing silver coinage, we are not aware, but from official data in our own possession we are prepared to assert that 10 per cent. is much nearer the truth. As no half-crowns have been stamped at the Royal Mint for fifteen years, and many are annually transformed at that place into florins and smaller pieces, it is clear that the former are being withdrawn from circulation, whatever thepresent intention" of the Government may be in regard to them." It would be far better, however, were half-crowns extinguished suddenly and not allowed to die a lingering death.

but this article having undergone a long and done in the rear. After this round the 3-inch tedious improving process, has now come out iron mantlet was removed, and an examinafrom the most severe trials a decidedly supe- tion was made, but no damage was visible in rior substance to gunpowder for blasting and the proper wall of the target except where mining purposes. As lately demonstrated by the 10-inch shot had gone through on the us,* the safety gun cotton now manufactured previous day. Round No. 2 was a 7-inch by Messrs. Prentice and Co. is absolutely Palliser shot which struck in section A (8safe under ordinary conditions, merely inch plate); the shots broke away, leaving blazing up, and not exploding, upon ignition. the head sticking in the plate. Round No. 3 When, however, it is tamped well home for was a similar shot to the last, and which work, its latent energy is fully developed. struck section C on the 6-inch plate with On the one hand, it is safer than gunpowder, hollow stringer backing. The penetration and on the other it is far more powerful. was 12in., the head breaking off 3in. in the The presence of the element of safety is plate, and no damage being done in the rear. For the fourpenny-piece, though once a guaranteed by the fact that the North- Round No. 4 was also a 7-inch Palliser shot, popular coin, no one has a good word to say. Eastern Railway Company now carry the and which struck in section D upon the 4-inch In companionship with the threepenny-piece safety gun cotton as ordinary goods in plate with channel-iron backing. The shot it is simply detestable. It is also perishing covered waggons. We believe other rail- penetrated 114in., breaking off and leaving by instalments, instead of being put out of ways are following this sensible example, and the head in the plate. A 9-inch Palliser its misery at once. We recommend summary hope it will lead to the general adoption of shot was then fired at the 8-inch plate on the measures in regard to these three denomi- gun cotton in place of gunpowder for blast- A section, and, for the first time, the Palliser nations of coin, because their disappear-ing purposes. For military or sporting pur-projectile buried itself in the target withposes it is not yet quite adapted, although out breaking up, about 4in. projecting from experiments now being carried on, we from the base of the target. The sixth round hope to see it so utilized before long. We was another 9-inch shot directed at the 6-inch will close with a note of warning to all nitro-plate with the pier at the back in section C. glycerine users, who, with every precaution, It penetrated the target 17in., leaving, like are in a far more dangerous position than the previous shot, the remainder projecting, even with gunpowder. They may be ex- though in a shattered condition. It entered ceedingly careful at first, but the very close to a bolt without injuring it, and four slightest deviation from the very greatest or five inches from a previous shot hole, withcare, into which they may be betrayed by fa-out cracking the intermediate plating. miliarity with danger, may be attended by Another 9-inch shot struck the 6-inch plate the direst results. and penetrated 19 in.

ance would be advantageous in all ways, and because, when transformed into shillings or sixpences, a useful future would still be in store for them. Convinced of the necessity of such amendments of the silver coinage as have been advanced in this and preceding papers, they will be persistently advocated, although at some risk of a charge of reiteration. It was a work of time to achieve the re-modelling of the copper coinage of the realm. Now that that work has been accomplished, every one admits its value, and we cannot regret the time and space devoted to its advocacy on the part of the MECHANICS' MAGAZINE.

NITRO-GLYCERINE.

RECENT GUNNERY EXPERIMENTS

AT SHOEBURYNESS.

left

The 10-inch gun, with a 60lb. powder charge, was then brought to bear upon the square A of the casemate. The shot went through the 8-inch plate and the concrete beyond, with a total penetration of 3ft. 6in., B second atyr's firing against the War EFORE entering upon the details of the starting, but not splitting, a bolt which it BOUT three weeks since we were startled A grazed along its course, and distributing by a telegram from Stockholm which Office casemate, at which point we left off some small fragments of concrete from the announced the explosion of a nitro-glycerine in our last notice, we would draw our readers' top of the pier. Round No. 9 was another manufactory and the death of a large number attention to pages 10 and 11 of our present 10-inch shot, which struck on section C, of persons. Since that time a discreet silence number, where they will find engravings of passing through the 6-inch plate, stringers, appears to have been observed upon the sub- the objects of attack which have been pre- and backing, and flying in two parts far out ject-at least, we have not seen any details of viously described by us. These consist of a to sea. It scattered fragments of iron-plate the matter, although we have looked for them. front view of the entire structure, showing over the casemate floor, shivering the wooden This reticence may be favourable to the in- the Plymouth shield, with the extra covering screen, and pounding the concrete and bituterests of the nitro-glycerine vendors, but the plate close to and at the west or proper men into a dense cloud. At the rear a dangerous character of the compound con- side of the porthole. Beyond this comes the large piece of iu. iron-plating for holding in tinues to advertise itself-a terrible explosion War Office casemate, covered with plates of the concrete was broken away and thrown on having taken place at the close of last week various thicknesses, as denoted by the figures the floor of the casemate. The destructive at Quenast, in Belgium. It appears that a on our illustration. We also give a sectional effect was probably heightened here by the waggon, accompanied by M. Grillet, of a plan of the entire work and two sections, one bad arrangement of the stringers, to which Hamburg firm which manufactures this dan- through the Plymouth and the other through we referred last week, and which, had it been gerous article, brought 2,000 kilogrammes the War Office casemate. different, would probably have modified the (4,411lb. English) to the quarries belonging Turning to the second day's operations result. The tenth round was a 9-inch shot, to M. Zaman, where it was to be used in against the War Office casemate, which took which struck the 4-inch armour-plating in blasting operations. The people employed place on Tuesday week, we find that the section D, completely penetrating it, breakin the works and those in the neighbourhood structure stood a vast amount of heavy ing off three 24-inch bolts, and hurling 13in. had been persuaded that this chemical pro- pounding, and was only finally placed hors de of one of them to the rear. A 10-inch shot duct was more efficacious and less dangerous combat by a 600lb. shot. It will be borne in was next fired at the edge of the porthole, than gunpowder. That it is more efficacious mind that this target was divided into six which it struck, broke into fragments, and, we admit, but that it is less dangerous we main portions, each lettered from A to F, glancing obliquely in an easterly direction, strongly deny. The waggon arrived at the and each being constructed upon a principle toppled over a couple of 6-inch armourquarry, followed by M. Grillet, three soldiers, slightly differing from the rest. For the de-plates, temporarily fixed at the side of the and two workmen to unload it; two car-tails of these principles we refer our readers casement, and went away out to sea. penters were working at a little distance, and to column 1, page 484, of our last number, interior brickwork of the casemate was much a young girl was close by. Suddenly a tre- merely observing that the principal feature smashed about by this shot. The twelfth mendous explosion took place. The persons was the introduction of Mr. Hughes' well- and final round was fired from the 12-inch just mentioned disappeared in an instant, known hollow iron stringers. They were Woolwich gun, the heaviest in the service. having been blown to pieces, and the shock originally invented by Mr. Hughes for was felt at Loth, eight miles off. A store armour-plated ships, and have promised so close by was quite destroyed, and the houses, well that the War Office resolved to test trees, and fields within a circle of 500yds. them to ascertain their value for coast dewere devastated. No other lives were lost, fences. It is claimed that as a system of but had the explosion taken place a quarter backing it is superior to the combination of of an hour later, when the quarrymen had iron and wood once so popular, and that, assembled, the catastrophe might have been by giving a minimum of material with a much more terrible, as 700 men are employed maximum of strength, it is much cheaper in the works. In the face of the terrific acci- than costlier defences not a whit more efficient. dents which have taken place since the intro- Another point in its favour is that, being a duction of this treacherous compound, we are thinner structure, it takes up but little room, much surprised to learn that any can be igno- an advantage, however, that applies more to rant of its dangerous nature. It is evident ships than forts. The first round fired on that although much improved since its first introduction, it yet remains a highly unsafe explosive, and one by no means to be depended upon. We thought and wrote so once-and more than once-of gun cotton,

the second day's trial was a 9-inch Palliser
shell, which struck the 6-inch armour-plate
with hollow stringer backing (section C). The
penetration was 164in., and no damage was

* MECHANICS' MAGAZINE, May 22, 1868, page 281.

The

The shot, which weighed 600lb., and was propelled by 761b. of pellet powder, was directed against the left port jamb, which had been weakened by previous shots acting on the surrounding portion. We need hardly say that this heavy round swept through everything, making fine dust of the concrete. and clearing all before it. The shot struck in such a position that four shot holes were battered into one large ugly gap. The plate, which was 4in. thick, cracked across on either side of the aperture, and the bottom portion of the severed piece of plate was forced out in proportion as the top was bulged in. The concussion that followed this was most disastrous to the heavy granite basement, from which two immense blocks were detached, while numerous fissures appeared in the reinainder.

Amongst the rest may

character, which was maintained thoughout THE AERONAUTICAL SOCIETY OF tical sticks on one horizontal stick, to which

more decidedly than it ever had been previously. The new 10-inch and 12-inch guns have proved themselves too heavy

GREAT BRITAIN.

N our notice of the opening of the Aero

weight of material presented to them in this I nautical Exhibition at the Crystal Palace the other its distance horizontally. reel is

target, and this at once points to the necessity of adopting the maximum thickness of plate now produced, one of which-John Brown and Co.'s 15-inch plate-stood fire so well the week before last, unbacked and nearly unsupported. Against the 7-inch and 9-inch rifled guns this structure possesses ample security; but more than this is required in the present day, and under the present conditions of artillery.

This experimental target has received thirty- Co., of Sheffield. About a month before the the Crystal Palace. two shots in its lower half, whilst the Plymouth opening of the bridge it was formally tested be noticed a working model of an aerial steam target has received twenty-two over its whole by the town council of the city of Prague. carriage, by Mr. J. Stringfellow, the whole, area. Looking generally at the results of the The test consisted in loading the footpaths including engine, boiler, water and fuel, two days' trial against the War Office structure, with bricks equal to a load of 80lb. per foot weighing about 12lb.; cylinder, 1 3-16ths we find them favourable to the compound super. While this load was on, a double inch diameter; 2-inch stroke; works two backing as against the plates and bars of the line of vehicles, each loaded with four tons propellers, 21in. diameter, about 600 revoluPlymouth shield. The most telling shots of old rails, was driven on to the bridge, re- tions per minute; gets up steam of 100lb. were those which were placed on the weakest maining there for about ten minutes. The pressure in five minutes. Mr. Thomas Moy, part of the target, which can certainly be total deflection obtained with the bricks and whose name is not unknown to our readers, strengthened by a more judicious combination the moving load was 77in., the calculated exhibits a working model to illustrate a mode of the stringers with the plating. The use deflection having been 8in. After moving the of flying vertically, by direct action on the of concrete in such a structure has proved to loads a permanent set of fin. was registered, air, without any screw motion in the wings. be a misapplication of that material in every the test giving entire satisfaction. The bridge This model will ascend in a vertical line. He respect, and cannot be defended upon any is 820ft. long between abutments, and 32ft. also has a working model to illustrate natural principle. It possesses no resistive value, wide. The total cost was £57,000. Both in flying, the wings being used to propel and and is decidedly noxious in the wide and design and construction the bridge reflects sustain; the tail to sustain only. This model liberal dispersion of its constitutent pebbles great credit upon the engineer and all con- will fly horizontally for a short distance. Mr. when broken out by shot, or blown wide-cerned. It constitutes an ornamental feature Moy also exhibited a mariners' kite for use cast by the explosion within its mass of loaded on the river at Prague, besides being an in rough weather, to communicate from one shells. With regard to the quality of the eminently useful structure. ship to another, or to the shore. It is plates, there can be no question of their high rectangular, and stretched between two verthe loop is attached. The kite is ballasted and attached to a float. It has two strings: one regulates its height from the float, and last week, we stated that the present was exhibited, by which one string only, or both, only a preliminary to a great exhibition, can at the same time be let out, held fast, or which it is proposed to hold next year. This wound in again. being so we must not expect to find it either Professor Ansell sent a model illustrating very perfect in its general character, or very a proposition to omit ballast in balloon interesting in its details. There are, how- ascents. By this proposition gas would be ever, some machines which show a consider-withdrawn from the balloon by an air-pump, able advance in the science of aeronautics, which would compress the gas into a chamber whilst all bear evidence of thought and patient carried in the car when a descent becomes labour, although unfortunately it has not necessary. An ascent will be obtained by always been applied in the right direction. opening a tap, and thus allowing the comThe general impression left on the mind by pressed gas to escape from the chamber by a the exhibits is one of incompleteness and tube into the balloon. The advantages of impracticableness. In some instances we this would be that the natural balance used have machines very well designed for aerial by fishes would be applied to balloons, gas flight, but which require the impossible addi- being reserved for use, instead of escaping, tion of great power to sustain them in their as now obtains. The Duke of Argyll exflight. On the other hand, there are excel-hibited a working model, showing progressive lent engines light enough perhaps for practical motion by flapping action of the wings. By flight, but too light for safety. All seems winding up a clockwork arrangement the model and theory, and there is really very little wings flapped away beautifully, and the whole beyond. It is, however, well that such an machine, which was suspended by grooved exhibition has taken place, as it will give wheels from a horizontal wire, made about each an opportunity of examining into the 12in. of progress. But we are not at all various principles presented to his notice, sure that this progress was not due to the and may eventually lead to a practical result. vertical vibratory motion of the wire. At present, while giving all credit to our Indeed. his Grace does not imitate the inventors and improvers, we have really got action of a bird's wing, to begin with, as but little beyond the old Nassau balloon of we can prove, if he considers it worth while twenty years ago-except, of course, in disputing. Mr. Shill sent an ingenious theory. The balloon, "Le Captif," of 1-horse power turbine injector steam engine M. Delamarne, was the only aerial vehicle weighing less than 121b. with inclined in which the public were invited to mount vanes showing its adaptation for aerial puraloft, and even this unfortunate sole repre- poses, with rudder and gear for working. to Steam here injects water against the turbine, and the force of impact is said to do all that can be desired. The inventor told us he had worked the machine, but he could not admit that he had obtained any available power from it. Mr. Spencer showed a flying machine which, being attached to the body, enables a person to take short flights. The exhibitor of this machine says he has, with less perfect apparatus, accomplished flights to the extent of 160ft., rising from the ground by a preparatory running action; we may, therefore, expect great things of the present apparatus before the exhibition closes.

Finally, with regard to the Rodman 15-inch smoothbore gun, we confess that its early trials inspired us with confidence. But we waited for competitive experiments with our own rifled guns to obtain a fair value of its merits. We now have this, and find our confidence shaken. It is urged that the material of the shot is inferior to that of our. own deadly projectiles. Here, then, is a chance for the friends of the Rodman gun to save it from utter discredit. Let them cast some spherical shot, on the Palliser principle, and then have a fair stand-up fight with our 10-inch or 12-inch rifled gun. Should it still lag behind, we opine the only thing to bring it up to its work will be to hand it over to Major Palliser to convert; when he has brought it into a fit state to swallow some of his chilled projectiles, we may hope for better penetrative results.

OPENING OF THE FRANZ JOSEPH

BRIDGE AT PRAGUE.

E have occasionally referred to the con

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We have occasion my resuspension bridge sentative of practical aeronautics came
over the River Moldau, at Prague. This grief on Saturday by burning. This event
bridge is built on the rigid suspension prin- is to be regretted, as it was one of the prin-
ciple of Mr. R. M. Ordish, of Westminster, cipal attractions of the exhibition, and was
the application of whose system in the pro- to make ascents daily to the height of 1,000ft.
posed Albert Bridge over the Thames at On Saturday, M. Delamarne made an attempt
Chelsea was described and illustrated by us to inflate the balloon by his new process,
in the MECHANICS' MAGAZINE for January 13, and the arrangements were inspected by
1865. The Franz Joseph bridge at Prague several engineers acting upon the exhibition
has now been completed, and was formally committee and council in the interest of the
opened on the 21st ultimo by the Emperor public. The stupendous machine appeared
of Austria in person. The day after the to be fully inflated in twenty minutes, and
opening, the Emperor, in an autograph letter then commenced to oscillate. Upon the
to the mayor of Prague, Baron Von Kellers- fourth oscillation, the heating apparatus (the
perg, expressed the pleasure he felt in open- whole weight of which rested upon the car)
ing the bridge, and observed that the city was overturned, when instantly the balloon
of Prague had chiefly to thank Ritter Von caught fire upon the south side, where it
Belsky (the late mayor) for having promoted burst, then fell to the ground blazing, where
and brought this undertaking to a successful it lay and smouldered to ashes. The sym-
issue. The bridge, as already observed, was pathy which was shown to M. Delamarne
designed by our countryman, Mr. R. M. by those around was very gratifying,
Ordish, on whom the Emperor has conferred and Mr. Coxwell, mounting an extemporized
the Austrian gold medal of Arts and Sciences. platform, soon collected together a good
The resident engineer, Mr. Charles Wessely,
received the Austrian golden cross of merit.
Several other decorations were given by the
Emperor on the occasion. The general con-
tractors for the bridge were Messrs. Ruston and
Co., of Prague and Vienna; the steel links were
supplied and erected by Messrs. Howell and

nucleus for a subscription, which he handed
to Mr. Brearey, honorary secretary of the
Aeronautical Society, to whom we refer those
of our readers who may wish to assist in
compensating M. Delamarne for his disaster.

We have said that there are a few exhibits
which are a step in advance of the rest at

The merits of the various machines, and the practicability of aerial navgiation by means of a flying machine, were discussed on Wednesday evening at the Society of Arts, in the Adelphi. Mr. Moy, whose plan chiefly called forth the criticisms, gave a mathematical description of his machine, by which he believes it possible to float through the air at pleasure, and at a speed of 150 miles an hour. The wings of his apparatus he proposes to work by steam, with one of Field's or Jordan's engines. 14-horse single cylinder engine to the ton would be required, and the machine itself would have two wings and a tail, each exertng a third of the rising and propelling power.

A

He had no confidence whatever, he said, in the screw or balloon, and thought he should be able to attain any altitude, or simply skim the surface of earth or water, just as he liked, and descend at will. In a word, he would have the same means as an eagle or albatross of flying to whatever spot he might select, and to sail and steer through the air with the same security and ease as a steamship gets over the sea. Mr. Wenham (one of the few practical disciples of Icarus) approved, and admitted all the data, but thought the power of flight could be tested by less expensive means, and suggested that the Society should for the present confine its attention to demonstrating that a man could fly by a single pair of wings. Mr. Stringfellow enthusiastically declared that the world should yet see that he could fly with his own machine, and this opinion seemed to be universally held by those present. Mr. D. J. Brown suggested that a better agent, because less expensive and easier of carriage, would be liquefied gas obtained from carbonic acid, but this view was controverted by Mr. Ansell; and so the various features of the plan continued to be canvassed until the time for adjournment arrived, which was somewhat late. And here the question rests for the present. Next week we shall have to record the awarding of the various prizes, and any further conclusions that may be arrived at.

THE PHENOMENA OF NATURAL

"THE

PHILOSOPHY.*

who, from unforeseen circumstances, have but for the whole work. Our space does not little knowledge of mathematics. We are permit, or we would willingly linger over this not aware that M. Guillemin has published subject and endeavour to give our readers his work with the intention of being made some idea of the gratification we have peruseful in juvenile education, but from what sonally received in perusing the pages which we have seen of it ourselves we consider it the author throws-assisted by the artistpre-eminently qualified for that object, to so much light on. Amongst the various which the excellent manner in which it is matters entered into under this heading we produced, together with the copiousness and find colour, the rays of the solar spectrum; beauty of its illustrations, would no doubt solar, calorific, luminous, and chemical radiacontribute in a great manner. tions; phosphorescence, double refraction of light, polarization, and chromatic polarization, and, finally, the eye and vision. From this book we make the following extract, which introduces the chapter on colour:-" The light which professors take as a type of all the others from the point of view of colour is that of the sun.

With regard to our remarks, and also to the subjects treated of, let M. Guillemin speak for himself. "Gravitation, sound, heat, electricity, light, such are the classes under which the phenomena, whose description is the object of this work, range themselves. We do not, however, limit ourselves to a simple exposé of facts. We have endeavoured to grasp their intimate relations in other terms, their laws-a task perhaps a little arduous when we do not call to our assistance a language so clear and so simple as that of mathematics. We have conceived and arranged this new work in the same spirit as our work on astronomy called 'The Heavens;' that is as much as saying that we have neither had the idea nor the pretension of writing a course of physics. We have endeavoured to remove obstacles from the path of those who wish to push their studies further; wholly, in giving to the people of the world a sufficiently clear and correct idea of science." A work given to the world with successful, command our respect. That the such laudable intentions would, even if unvolume before us carries out largely the author's pleasing language, we trust the extracts and remarks we are about to make will sufficiently prove.

HE human mind has ever felt the imperious necessity of knowing the laws which regulate physical phenomena, to grasp Nature, to seize her in her most mysterious Passing the first part on gravitation, which operations; in a word, to render itself master, contains most excellent chapters on gravity. so as to make her useful as well to the wants specific gravity, and the weight of air and of of material life, as to those of the moral and gases-we must not omit some excellent deintellectual. Such is the noble enterprise to scriptions of barometers-we come to the which the greatest minds have devoted them-second part on Sound," which may be

selves."

We have thought that the above extract from the preface of M. Guillemin's work on Natural Philosophy, having formed the introduction to his book, might not inaptly form that to our review. It is not a very usual custom on our part to notice new books that appear printed in a language other than our own, but when we happen to have before us a work on such a subject, and written and produced in so excellent a manner, we wish to present to our readers an opportunity of indulging in a gratification in which we ourselves have already indulged.

The study of natural philosophy in all its branches has been one that formerly had not that attention given to it in our educational establishments that so interesting and necessary a subject required. We are glad to say that in this respect we are progressing, but even yet there is great room for improvement, for we find this study postponed in a great measure until students have advanced a great deal in age. Were the subject to form a part of earlier education, we doubt not beneficial results would follow; it is, perhaps, in some measure owing to the fact that the principal and fundamental laws of physics depend upon mathematics for their elucidation. Now, as mathematics are, to our great regret, rarely taught in our general schools, except to pupils of advanced age, the study of physics becomes naturally more difficult. Works, therefore, that tend to the elucidation of natural philosophy and its laws, that are not entirely dependent upon mathematics for their explanation, must be especially welcome, not only for the instruction of the young, but for those of riper and maturer age, and for those of advanced life

* "Les Phenomenes de la Physique." Par AMEDEE UILLEMIN. Ouvrage illustre. Paris: Librarie de L. Cachette et Cie.. Boulevard Saint Germain; and French Hublishers, 18, King William-street, Charing-cross.

66

looked upon, from the matter dealt with, and the way it is illustrated, as being second to none in the book. Introducing the subject of the phenomena of sounds in Nature, the author remarks:-"The absence of all sound, of all noise, in a word, absolute silence, is for us synonymous of immobility and of death. We are so accustomed to hear, were it only the noise we make ourselves, that we can with difficulty conceive the idea of a world completely silent and dumb, such as the moon appears to be if we believe the notions of astronomers." The continuation of this chapter is beautifully written, and the ideas clothed with elegant language, which the book teems with throughout. Some interesting details are given of various experiments performed for the determination of the speed of sound through air and through water and other bodies. On sonorous vibrations we have full explanation, and a series of most interesting illustrations, giving the peculiar forms assumed by a combination of movements. Of the optical effects of sound we are treated to numerous illustrations, amongst which we cannot but notice the peculiar effect of sound upon flames, which formed, as many of our readers may remember, some of the many interesting experiments shown by Professor Tyndall at the Royal Institution. Sound is further described in its relations to hearing and to the voice, the accompanying illustrations explaining very carefully the physical formation of the human organs concerned.

"The light of the sun is white. A very simple experiment demonstrates it. If, in the interior of a dark room, the solar light be received direct on a screen of white paper, after it has passed through a hole pierced in the shutter, the image of the sun on the paper, as is well known, will be a spot round and white." "But this white light is not simple. It is composed of a multitude of colours or of tints which are themselves so many simple colours. This fact has been placed beyond doubt by a series of experiments varied in every form, but which, for the most part, are due to Newton.

"Let us indicate the most conclusive. A triangular prism of flint glass is placed, in sage through the round hole in the shutter of the course of the solar rays, after their pasthe dark room in such a manner that its edges are placed horizontally, and that the luminous pencil penetrates obliquely through one of its faces. Then you perceive upon the screen, instead of the round and white image of the sun, and at a certain distance above the point where it formed before the interposition of the screen, a bright elongated streak formed of a succession of extremely bright colours. It is this streak that is called the solar spectrum." Amongst the illustrations upon this subject we may specially mention the coloured ones, that of the soap bubble, forming the frontispiece, being one of the most remarkable coloured illustrations we have ever seen.

The remaining books are devoted to heat, magnetism, electricity, and atmospheric meteors. Under the last-named book we find a variety of atmospheric phenomena, such as optical meteors, the rainbow and mirage, hygrometry, clouds, rain, and snow, crystals of snow and ice, electric meteors, lightning and thunder, and the aurora borealis. The heading is not sufficiently comprehensive, for we find subjects treated under it that properly do not belong to that subject.

Under electricity, we find frictional and current electricity well explained, electromagnetism and induction, and an exceedingly interesting chapter on the electric light as produced by means of ordinary friction machines and by induction coils, and the voltaic arc as produced between carbon points, by a series of voltaic elements. We cannot pass without notice some very pretty experiments on the effect produced by the discharges from the two coatings of Leyden jars upon a resinous cake peculiarly prepared, which demonstrate the distribution of the two kinds of electricities.

In a work of this sort, where we find so much to praise, it were almost invidious to make extracts from any one part rather from any other. We have been content, therefore, to The third book is devoted to "Light," and describe generally what the book contains we really cannot find terms sufficiently ade- rather than dilate upon some few pages; those quate to express the manner in which the who wish to enquire more minutely into any subject is elucidated, particularly as regards of the various subjects will be amply repaid the diagrams and illustrations. The various by an investigation into the book itself. forms of reflection and refraction, even to the Suffice it for us that the task of giving this, explanation of the "ghost mystery,” are care- and noticing the work, has been from beginfully set forth. Diagrams are given of the ning to end a source of great gratification and angles formed and images produced, and, in-pleasure. There is often to be heard the constant deed, this part alone is worth the value paid cry of "they manage these things better in

France;" now, as a rule, we have never held of caustic soda in 100 cubic centimeters of dis-side and rough on the other to represent the grain to that opinion, feeling sure that we can do tilled water. For the third or reducing solution and flesh sides of the leather. The addition of the things over here equally as well, but, in the two grammes of pure glucose are dissolved in 24 raw fibre with the tanned filaments is in certain propresent instance, we are bound to make cubic centimeters of distilled water and 24 cubic portions, according to the quality of the leather an exception, and record our opinion that centimeters of alcohol, and to these are added 24 required, from five to twenty per cent. can be amongst the various scientific works we have cubic centimeters commercial aldehyde. This safely employed. It gives vitality to the tanned ever met with that have been published in solution must be prepared on the day on which it fibres by agglutinating them and imparting the is to be used. When the vessel to be gilt is albumen and gelatine which has been destroyed England, we cannot remember one that has ready, its capacity must first be ascertained, so by the tannic acid. To render the compressed been produced in so excellent a manner as that none of the solution need be wasted. Then leather more supple or flexible it is necessary that now before us. Whether we take the it is to be half filled with a mixture composed of occasionally to incorporate about one pint of beauty and clearness of the language, the four volumes of the gold solution (No. 1), one glycerine to a hundredweight of mass. In the manusimplicity of the explanations, or the volume of the soda solution (No. 2), and one-six-facture of shoes, boots, and similar articles, and wondrous perfection of the illustrations, it is teenth of a volume of the reducing solution other purposes for which leather is employed, the the same. The work throughout is illustrated (No. 3). As soon as this mixture is introduced, compressed leather will become of great importance in a hitherto unparalleled manner. The the globe must be moved rapidly about so that the from the fact-and we speak advisedly, having seen diagrams, descriptions, and pictures are most whole of the interior surface may be kept wet, and, some specimens that it is less permeable than in a very short time, a brilliant coating of gold will ordinary sole leather. It is also harder, closer, and carefully done; many of the illustrations are be given to the whole surface. As soon as this is more compact, and can be sold to the consumer at drawn with that care and finish that we alone deposited, the excess of solution may be poured out, fifty per cent. less than the natural hide. see in that special class of book, the "gift the globe dried, and a coating of varnish applied not suited for machine bands, or harness, but in book," such as poetic illustrations, and so to give permanent protection to the gold. If a the manufacture of boots and shoes, especially for forth. With regard to the coloured illustra-thicker layer of gold be desired, the process may nailed soles and heels, as also for inner soles, it is tions we can only say that they are unequalled. be repeated two or three times-of course, before also superior to much of the materials at present We cannot close our notice without thanking any varnish is applied. When we spoke of waste employed. On the whole, we are much pleased the author for so fully carrying out his just now, we meant of solution; none of the gold with this invention, which is a step in the right laudable intentions, and giving to the world need be lost. What is not deposited upon the glass direction, and proves that in another great departso valuable a work. We can only regret that will be left floating in minute flocculi in the solu- ment of economic industry the importance of it is written in French instead of in English, Incineration of the filter will, of course, give the trust that the results of the inventor's ingenuity tion, and can easily be separated by filtration. utilizing waste material is fully recognized. Wo as thereby many of our countrymen are gold ready for solution in aqua regia and another will be duly appreciated, and that success will deprived from reading what would be at once operation. When a flat surface or mirror is to be attend his efforts to inculcate the practical lesson to them a source of enjoyment as well as of gilded, it is only necessary to form a shallow tray that Nature teaches us of knowing no waste. instruction. and keep the solution in movement as above described.

We have already published several methods of NOTES ON RECENT SCIENTIFIC DIS-giving a thin coating of copper to iron and steel. COVERIES AND THEIR PRACTICAL The following, which will not give so good a coatAPPLICATIONS.

MEANS OF MAKING PAINT TO ADHERE TO ZINC-A

FOR GILDING GLASS-SIMPLE MODE OF GETTING
A COATING OF COPPER ON IRON OR STEEL.

It is

THE ROYAL INSTITUTE OF BRITISH
ARCHITECTS.

ing as Grager's, which we published some months ago, may still be recommended for the extreme ease with which the end is accomplished. The ON Wednesday evening last the rooms of the NEW ALLOY FOR STEREOTYPE PLATES-A PROCESS iron or steel, made perfectly clean by scouring with Conduit-street, were thronged by those who atRoyal Institute of British Architects, in a scratch brush, is then moistened, and powdered tended the conversazione of the president, Mr. cream of tartar, drenched with a saturated solution of sulphate of potash, is rubbed over tho sur-rated for the occasion with flowers and evergreens, W. Tite, M.P. The rooms were tastofully decoface with a hard brush. The copper covering is whilst oil paintings and water-colour drawings, similar process to this we remember to have been said to be permanent and even. A somewhat in vogue some years ago, but this is a decided simplification.

is a difficult matter to get a coat of paint to ITi adhere well to zine, which rapidly oxidizes when exposed to air and moisture; and, as most engineers know, galvanized iron goes very quickly when once the covering of zinc has decayed. Many means have been tried to obtain the firm and close adherence of paint to zinc. The last we have met with is due to Dr. Bottgor, who professes to have completely succeeded. He makes a solution of one part of chloride of copper, one part of nitrate of copper, and one part of chloride of ammonium in sixty-four parts of water and one part of commercial hydrochloric acid. This solution acts as a sort of mordant. It is paid with a wide brush over the zinc, which immediately becomes of a deep black colour, forming, according to the Doctor, a basic chloride of zinc, and what he calls an amorphous brass. The black colour changes in the course of 12 or 24 hours to a grey, and upon this grey surface any oil paint will dry and give a firmly adhering coat. Summer heat and winter rain will have no effect in disturbing this covering, which affords complete protection to the zinc.

A very hard alloy, fit for stereotype plates and for backing up electrotypes, may, we read, be made by melting together 500 parts of lead, 300 parts of tin, and 225 parts of cadmium. It is said to be a harder alloy, and better for the purpose than that made with bismuth, and will certainly be cheaper. One thing is to be said against it, and that is that when remelted some of the cadmium will be volatilized, and thus the composition, and, to a certain extent, the properties of the alloy, will be changed. By a little care, however, to melt at as low a temperature as possible, and by adding a small quantity of cadmium, the composition may be kept pretty uniform.

COMPRESSED LEATHER.

There were numerous objects of interest besides architectural and otherwise, covered the walls. the purely architectural or artistic contributions. For instance, Mr. Tite lent a collection of all the earliest editions of Shakspeare's works in single plays. This unique collection is almost priceless in its value. The books are all single plays, pub

lished separately, and of the earliest date, from

IN noticing this invention, we are actuated simply
by a desire to place before our readers another 1593.
of them include what are now
instance in the progress of science in utilizing the considered as not being Shakspeare's own works.
refuse and waste cuttings of leather, which have Still they were published in his name and during
been considered almost valueless, but which are his lifetime, though these antique proofs yet leave
now being converted into a valuable article of the correct autograph of the great poet's name as
commerce. The inventor of the compressed doubtful as ever, for not more than one or two
leather, Capt. J. H. Brown, R.N., has devoted his agree in spelling it as it is generally received at
energies for some years past to converting the present. In a case close adjoining was a copy
refuse cuttings of animal hides and skins into of the "Times" of 1793, not so old by some
useful products. We remember his patent parch-years as those kept in the archives of the "Times"
ment and vellum skins, which, during the excise
duty on paper, were brought before the Court of
inventor objected to the impost on the grounds
Exchequer as being subject to that duty. The
that as it was made from animal skins, and not
vegetable fibres, it was exempt from the duty, as
parchment and vellum skins were. In the course
of the trial, sheets of the patent parchment were
exhibited-some of them engrossed. The court
admitted that had they not seen the specification
they would have called it parchment, but being
manufactured in a paper mill, and being reduced
into a fibrous pulp and fabricated into sheets in
the same manner as paper was, it came within the
meaning of the Act of Parliament, and therefore

There was also

office, but still old enough to illustrate by com-
parison the strides by which the "Times" has
the lay gospel of England."
gradually risen to be what it is called in France
a splendid book of illuminations from the hand
of Mr. Owen Jones, and an interesting selection
of chromo-lithographic views. The band of the
Coldstream Guards enlivened the proceedings
with well-selected music, and a very agreeable
evening was passed.

was subject to the duty. This decision had the A Friday evening last, at University College,

effect of preventing the progress of manufacture
for a time, but since the abolition of the paper
duty the works have been resumed, and in addi-
tion the compressed leather is being produced at
the Abbey Mills, Romsey, Hants.

The modus operandi in the manufacture of the compressed leather is the reduction of cuttings or waste of shoemakers into fine filaments, cleansing A process for gilding glass in the liquid way, them, in the first place, from dirt and foreign similar to that adopted for silver, was devised some matters. In the next place, the cuttings or refuse years ago by Wernicke. It was, however, uncer- of ox and similar hides, which are generally unfit tain, and has been recently improved by Dr. to tan, and are sold to the glue makers, are also Bottger. He makes three solutions, the first by reduced to a fibrous mass. These are combined dissolving one gramme of gold in aqua regia, and together with water, to which is added one part carefully evaporating so as to drive off the excess of sulphuric acid to one hundred parts of water, of acid, and get as neutral a chloride of gold as until it assumes a plastic mass, when it is pressed possible. The residue of chloride is dissolved in into moulds of the size and thickness required. 120 cubic centimeters of distilled water. The When dried in a steam-heated room they are second solution is made by dissolving six grammes passed through heavy pulp rolls, glazed on one

THE QUEKETT MICROSCOPICAL CLUB. MEETING of the above society was held on Arthur E. Durham, Esq., F.L.S., president, in the chair, when thirteen new members were elected, ten gentlemen were proposed membership, and numerous presents were announced. Several interesting communications were also received from societies on the Continent and in America. A paper on tobacco was read by Mr. Archer, in which he entered into the particulars of the growth, culture, and preparation of the plant, as well as its structure, constituents, manufacture, and adulterations, the subject being illustrated by a fine specimen of a living plant, numerous dried samples, and some well-executed drawings. At the close of the meeting the president announced that the annual general meeting of the club would be held on July 24, and the proceedings terminated with a conversazione, at which a variety of interesting microscopic objects were exhibited.

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