THE driven by a double cylinder engine of revolves upon an unyielding substance, and upwards of 20-horse power. The Hancock carries its load the entire length of the revoscrew is of an entirely new curve, as will be lution, without loss or slip. But as the screw seen by the annexed engraving; it revolves revolves, the water yields to its pressure, and MECHANICS' MAGAZINE. from left to right, that is, the concave face the fastest ships in the Royal Navy only LONDON: FRIDAY, SEPTEMBER 18, 1868. THE HANCOCK'S SCREW PROPELLER. HE many advantages offered by screw propulsion over the paddle-wheel system have led to innumerable improvements and modifications in the former principle. Some of these are to be taken for what they are worth-which is little or nothing-whilst others possess a practical value which has led to their adoption. Amongst the most recent inventions in this direction, and one which has given the most signally successful results under competitive trials, is the screw propeller of Messrs. F. and C. Hancock, of Dudley. This screw has recently been tried against a two-bladed Smith's screw with results entirely in favour of the former. In the interests of steam navigation, we propose to place before our readers all the facts we have obtained respecting this trial, feeling assured that the Hancock screw embodies elements of superiority which entitle it to every consideration, and which there is every HANCOCK'S SCREW. First mile, not full steam Half mile, ditto TOTAL......... Pres- Revolu- Time per run. Minutes. in lbs. Minute. 88888 22 68 1 23 23 80 1 21 17 8 46 moves forward. It is 3ft. in diameter, 6ft. obtain a speed of one-fourth the margin velocity It will be seen by the above statement that reason to believe will place it before every the Company's screw had double the presother competitor. The trial in question took sure of steam, and made upwards of thirtyplace in a steam tug belonging to the Shrop-five revolutions per minute more than the shire Union Canal Company, on one of their Hancock screw. It is, therefore, fairly to be lines of water near Wolverhampton. This inferred that double the quantity of coal was company for some years used a Griffith's consumed with the former, whilst a lower rate screw in their tugs, but the results being of speed was obtained than by the latter with any other screw. To these advantages unsatisfactory they instituted a series of screw. The value of a screw on a canal is its is to be added the economy of fuel, which is experiments, at a cost of several thousand power to carry weights behind it; experiments a most important feature in every case. The pounds, with the view of obtaining an efficient were therefore made in towing, and the tug establishing the superiority of the Hancock experiments have been very conclusive in screw propeller. These experiments led to boat took in tow four loaded boats containing the adoption of a two-bladed Smith's screw, ninety-five tons of goods. The first run of screw for one class of navigation. the blades each filling a quadrant of the two and a-half miles was made with a four-will prove as efficient in larger vessels, and whole circle, so that the entire screw area bladed Hancock screw. The pressure in the under different conditions, there is no reason is equal to half the area of the circumscribing boiler was 50lb. full pressure; the run was to doubt. But we cannot of course pronounce circle. No other form of propeller, Messrs. accomplished in 67 min., the engine making trials. The invention is one full of promise, a decided opinion in the absence of actual Hancock's alone excepted, has given such eighty-six revolutions per minute. The good results as this on the Shropshire Union Hancock screw was then removed, and the and we shall watch with interest the progress Canal, and it was one of these against which Smith screw put on, the boiler pressure what has already been done, that if a trial in of the Hancock screw, feeling assured, from the Hancock screw recently competed. The remaining the same. The same four boats, same boat was used in all cases, the screws with their ninety-five tons of cargo on board, an ocean vessel were made, and the results only having been changed as required. The were again taken in tow, and the run was screw shaft makes two revolutions while the accomplished in 65min., the engine making screw makes three, and the relative speeds of 148 revolutions per minute. the crank and the propeller shafts remained figures it would appear that nearly the same results were obtained in both cases with a very different consumption of steam, and, consequently, of fuel, highly in favour of the Hancock screw. In a third experiment with the Hancock screw, the boiler pressure being 60lb., the engine made 103 revolutions O sooner was the first flush of triumph over which celebrated the introduction four boats loaded as before, was accom- and practical efficiency of the railway system, plished in fifty-five minutes, upwards of than attention reverted to the old means of half a mile an hour faster than the run locomotion, which had been so suddenly cast with the Company's screw. Such a result into the shade. The great routes of inland was certainly never obtained with the or- intercommunication still existed, under the dinary screw. Although we have no exact form of canals and public roads, and the quesfigures as to the consumption of fuel, neither tion not unnaturally arose whether they might were any indicator diagrams taken from the not be adapted for their original purpose upon engine, there is evidence of a considerable an improved and increased scale by the applisaving in fuel. As this saving has been cation of the new power. In a word, could realized on the narrow and shallow waters of not steamboats be used upon canals, and locoa canal, we may anticipate similar results motives on public roads. To assert that this with increased speeds in ocean steamers fitted interrogatory has been successfully replied to with the new propeller. It should be borne in the affirmative would be untrue, and it in mind, that speed cannot be obtained, how- would be equally false to state that complete ever great the power used, in shallow canals failure has attended all the efforts made at where the boat draws four feet of water, as intervals to accomplish the desired result. was the case in the present instance, leaving Leaving out of consideration for the present only six or eight inches of water below the the instance of canal steam navigation, it may bottom of the tug-boat. It was found that be safely mentioned that although the appliwith the Hancock screw no vibration what-cation of steam power to ordinary road locoever was experienced, whilst in all cases with motion has not yet been sufficiently successful the Company's screw, and, in fact, with all to warrant it being styled un fait accompli; other screws, considerable vibration results. yet enough has been done to encourage the It was at one time hoped that a revolution expectation that the end may be attained at of the screw would be made to give a result no very distant period. Among the numerous analogous to that of a cartwheel. The wheel descriptions of locomotives constructed spe cially for meeting and overcoming the obstacles belonging exclusively to this kind of traffic may be mentioned a recent application of M. Rousseau, a mechanical engineer of Marseilles. He discards the old Roman type of axle and wheel, and constructs the large hind wheels of the road locomotive so as to revolve freely upon a fixed axis. These wheels are driven by belts, one to each wheel, and they can act either separately or in combination, or in opposite directions. each at the respective elevations of 1, 3, 5, 7, surmise were at once busy in assigning every and 9deg., and at the highest angle the car-possible description of cause to account for riage would admit of, and which proved to be the occurrence. Some asserted that the emi19deg., thus making 120 rounds in all. The bankment at Suresne had given way under charge used was in all cases the battering the pressure, and permitted the egress of the charge for the service 8 inch guns, viz., 30lb. turbulent waters. Others threw the whole of powder, the projectiles, both shot and blame, as is not uncommon in such cases, shell, weighing 150lb. On the first day, the upon the engineers, and accused them of experiments were discontinued after thirteen cutting a passage under the banks in order rounds had been fired, owing to the studs in to allow the water to flow off, that they might the projectiles being of too high a gauge; the more easily sink the second syphon which It has been demonstrated by experiment the wax lubricant of the wads also caused the was intended to carry the whole of the that one of the greatest evils to be surmounted gun to foul, and interfered with the shooting. drainage of La Bièvre across the river. with these locomotives is the tendency of the These defects, however, were soon made Neither of these two, or any other of the wheels to slip, especially when ascending an good, and practice was resumed the next, numerous guesses, were correct, but the incline, and when the roads are greasy, damp, and was continued on the two following following was the real state of affairs. or frozen, and when any of the trailing wheels days. After the defects in the wads and Since the middle of last month the works become imbedded in ruts. In order to obviate studs had been remedied, some exceedingly belonging to the new drainage scheme had these contingencies, the inventor has sup-good practice for accuracy was made. Thus, advanced to such a pitch that to complete pressed the bogy frame in front, which was at 5deg. elevation, and the mean range of them it was necessary to get the syphons simply pushed on by the action of the driving 2,805yds., all the shell fell within a space of sunk, which acted as the general collector of wheels, and substituted another, driven directly 5yds. wide; and at 7deg. elevation and a the storm and other waters draining from the by steam power. By this arrangement, the mean range of 3,597yds., 10yds. covered all left bank of the Seine. The syphons themleading wheels have complete freedom of the shot, and 9yds. all the shell, four of the selves, consisting of wrought-iron cylindrical action; this axle can be turned until it assumes latter, viz., rounds 76, 7, 8, 9, all falling tubes, are first rendered completely watera position nearly at right angles to that of the within a width of half a yard. The mean tight and then immersed in the river, where trailing axle, and the engine can be turned range was, at 1deg. elevation, 931-7yds.; at they float half in and half out of the water. right round within the distance of its own 3deg., 1,942-9yds.; at 5deg., 2,805yds.; at To accomplish this operation successfully, a length without the least difficulty. Another 7deg., 3,597yds.; at 9deg., 4,306-5yds.; and certain amount of current is required as well advantage accruing from this arrangement is at 19deg., 7,240yds. Only three rounds were at a certain depth of water, in order to bring that the adherence of the locomotive and its fired at this last elevation, as the tide began them right over that portion of the bed of tractive force is very much increased, since to cover the sands, and prevented the requi- the river which will constitute their ultimate not only is the whole weight of the engine and site measurements being taken. Up to this site. The first tube having been hauled its charge utilized, but there is also direct point the gun had fired 103 rounds, besides perpendicularly over the proper spot, was steam action upon all the points d'appui upon the two proof rounds, and appeared to bear uncorked, if we may use the term, and, after which the load is supported. There are con- the enormous charges without any sign of gradually filling, descended quietly into its sequently four points of contact between the being overtaxed, the interior of the bore up place without the slightest mishap of any engine and the ground, each of which is to this time exhibiting no indication of flaws kind. The success which attended the sink movable independently of the other, a condi- or deterioration of any kind. The practice ing of the first syphon was hailed as a good tion which is favourable to the steering power, was resumed last Monday to complete the pro- omen for that impending over its neighand does not allow the wheels to get stuck in gramme of firing 120 rounds, 17 of which had bour, but unfortunately some time elapsed the manner which is so notorious. to be fired, but owing to the platform getting before the omen was fulfilled. Upon A very common objection to the use of road out of order, and there not being time to re- the day fixed for its immersion, the velolocomotives is that the noise frightens the pair it before the rise of the tide, the practice city of the river had increased, and the horses, and the smoke blackens the houses, but was discontinued after firing 11 rounds, mak-level of its surface had fallen 6ft. The after the experience gained from the engines ing in all 114 rounds that had been fired with cause was the bursting of the dam of Grandeemployed on the Metropolitan Railway, the charges of 30lb. of powder and a projectile latter objection is not valid, and the former of 150lb. weight, besides the two proof rounds would cease to become so after a certain time. of 3741b. of powder and 150lb. shot. The range It appears that the locomotive of M. Rous- attained was slightly under that on the previous seau works without much noise, and without Friday at the same elevation of 19deg. The any smoke of an appreciable amount. It has initial velocities taken and roughly calculated been used in the midst of ordinary road traffic, were 1,500ft. per second, but owing to the and has been found to turn the angles of absence of Captain Noble, R.A., they have streets with perfect ease, even when dragging not been checked. The gun, which shows no after it four baggage waggons, each containing signs of weakness or deterioration under the about five tons weight of contents. For severe strain to which it has been put, has transporting marine boilers, some weighing been returned to Woolwich to continue the upwards of twenty-five tons, it has also been endurance test of firing 1,000 rounds with proved to be very serviceable, as it affords a 30lb. of powder and a shot of 150lb. weight. concentration of tractive and haulage power not to be obtained by any number of horses. While there is no doubt but that steam power SINKING SYPHONS IN THE RIVER the establishment of Chaillot, and their total might be employed upon common roads at small speeds, it is extremely improbable that it will be capable of application upon a scale admitting of a velocity exceeding that of the fast mail coaches of the olden times. As all is that of the syphon, and it is rather remarkwork performed by steam may be said to con-able that although the truth of its theory sist of two quantities, weight and velocity, it is evident that the former is the most important one to attend to, when that power is adapted to ordinary road traffic. THE PARSONS' GUN. SEINE. NE of the first apparent paradoxes pre is unquestionable, but little practical use has been made of it. It is said, and we believe correctly, too, that it requires a small steam engine to keep the syphons laid over the embankment in the mid-level free from air, and in working order. The dithculty of maintaining any enclosed space in an air or water tight condition, has always been A SHORT time since we mentioned that a recognized, and where syphons are concerned, cast-iron 68-pounder smooth-bore gun it has hitherto proved impracticable. In spite had been converted into a 150-pounder rifled of these preliminary warnings, the French gun, on the system invented by Mr. P. M. engineers have determined to lay a couple of Parsons. This gun successfully passed proof syphons under, or rather in, the Seine, for the at the Royal Arsenal butts, Woolwich, on the purpose of conveying the storm waters and 17th ult., firing two rounds with 374lb. of drainage from one side to the other. Jatte, at Neuilly, which, together with the increase of the velocity of the current, put an end to the preparations for sinking the second tube. It was accordingly towed to a place of safety, and made fast. As it was impossible to repair the breach made in the dam at Neuilly, and as the navigation was seriously interfered with by the sudden lowering of the water, recourse was had to the weir at the bridge of Jena, which was purposely adapted for such contingencies. By its means a sufficient head of water was ob tained, and the operation of placing the second tube alongside its predecessor proceeded with. The cylinders, of wrought iron, with countersunk rivets, were constructed at length from wall to wall of the river is about 450ft. After being sunk, they will be encased in an envelope of bêton, 16in. thick, to of anchors, the action of dredging, or any other cause that might be likely to damage them. There does not seem to be any cogent reason why the cheaper material, cast iron, should not have been employed in lieu of wrought in the construction of these tubes. They have no weight to sustain, no real work to do. We should have regarded an instance of this kind as one peculiarly adapted for the employment of cast iron, but judging from this case and that of the late Exposition, that material is manifestly not a favourite with continental engineers. RAIN-GAUGE EXPERIMENTS. revert to Mr. Symons's "British then removed to Shoeburyness for further other will be laid alongside in a day or two. ticing his account of experiments with ramtesting, which it underwent on Tuesday, A rather curious incident occurred in con- gauges. "Cui bono" may be chalked on the Wednesday, Thursday, and Friday, last week. nection with the state of the river during the rain-gauges, but he who writes it now only The trials were for range, accuracy, and progress of the operation. On a sudden, proclaims his own ignorance of the progress velocity, the programme being ten rounds of without any previous sign, the level of the of sanitary engineering and agricultural solid shot and ten rounds of common shell, river sank several feet, and rumour and science. powder, and 150lb. projectiles. This gun was has already been deposited in site, and the W Rainfall, 1867," for the purpose of no This may be true, but science demands exactness of method, and unless the initial observations are made upon well-defined and accurate principles, all results and inductions are necessarily unsound. Mr. Symons publishes annually the totals of the daily measurements from a motley assortment of rain-gauges. Of 1,140 of them, more than half have receiving apertures only five or less inches in diameter. Most of those used in Scotland are only three inches in diameter, and not a few only two inches. These economical implements are merely ginger-beer bottles with small funnels fitted over the necks. Data from such sources can be of no earthly use for scientific purposes. In England there are 420 rain-gauges five or less inches in diameter to 394 exceeding five inches; in Scotland these sizes are as 107 to 81; in Wales as 57 to 17; and in Ireland as 32 to 32. In our opinion, it would be better for science were all rain-gauges less than eight inches in diameter given up. In former volumes of the MECHANICS' MAGAZINE reasons have been adduced for this opinion, which have not been consistently controverted, and further experience with rainfall statistics have only confirmed them. August rain only 17deg. 29min.; and, as they which is easily detected and removed, and of should do, these angles agree very well with which the Act says the gas shall contain none, the velocity of wind as recorded by an ane- gas still contains a good deal of sulphur, the mometer. Except the small interest there exact amount of which no one knows for cer may be in ascertaining this coincidence, what tain, the estimation of which is exceedingly interest can result from experimenting with difficult, and the form in which it exists is gauges having their apertures inclined is not altogether unknown. Some of our first yet apparent. chemists have occupied themselves with this That portion of an oblique shower, A B, question, and their views and results are by which would enter the aperture of a circular no means concordant. How to remove this gauge, which is kept at right angles to it, and sulphur, too, is a question with which some of which C D represents the diameter, would eminent practical chemists have busied themall be received by a properly-constructed selves with as yet doubtful results. What horizontal gauge of elliptical aperture of which we do know, however, is that sulphur is a the major axis is CE, and the minor axis most prejudicial ingredient in gas; that it equals CD, the relation being that of a circle ruins steel goods, that it destroys.the colours to an ellipse in the same cylinder. If the of dyed and printed fabrics, and that it shower be supposed to fall at an angle of occasions a serious loss to silversmiths, and, 45deg. from the vertical, the triangle CDE indeed, to all owners of plate, and that it is will be right-angled at D. Then, if CD be very desirable to get rid of it, if possible. 8in., C E equals 11-314in. As it would be Take, again, the modes of estimating the inconvenient to make an elliptical gauge, a illuminating power. Which is the best phocircular one of equal area may be substituted. tometer to use? We use Bunsen's; the The aperture of this gauge would therefore French use Foucault's. What is the best require a diameter of 9.513in. Thus, a hori- standard of comparison? We use sperm zontal gauge of 9.513in. diameter and an in-candles, liable to all sorts of adulteration; clined gauge of 8in. diameter tried together, the French use the carcel lamp, with oil also We have always insisted on the desirability under the circumstances supposed, must neces- liable to adulteration. What, again, is the of uniformity in instruments and methods; sarily collect similar amounts of rain. But for proper burner to use? The Metropolis Gas we can, therefore, refer with much satisfaction all other directions of fall the relation of size Act of 1860 prescribed one notoriously bad, to the Rev. T. E. Crallan's account of experi- between the gauges ought to be varied in ac- which has been given up. What are we to ments made at Hurst Green, Sussex, to ascer-cordance to the geometrical principle, for substitute for it? We have said enough, we tain the respective merits of certain materials both to give the same indications. Hence, it think, to show that to perform efficiently the for rain-gauges, and of different forms of con- becomes impracticable to institute a direct duties of a gas referee a sound knowledge of struction. The results bear out our views comparison. But it is evident that a tilting chemistry is, at all events, necessary, to which entirely. He says:-" I should discard glass rain-gauge must always collect more rain than should be added a good acquaintance with and pot funnels, and, in fact, with them, all a horizontal gauge of the same size; and this some other physical sciences. When the substances which offer any considerable is all that any extent of experimenting with French Government wished to have the very amount of capillary attraction. A dull smooth them will show. points determined these gas referees have to surface allows the rain to run off it most freely. settle, Dumas, the first chemist in France, and As to construction, I have only to Regnault, the first physicist, were appointed. remark that the nearer the rim approaches the vertical in its exterior the better." A rain-gauge conforming to these views was described in the MECHANICS' MAGAZINE for May 18, 1866. GAS REFEREES AND THEIR QUALIFICATIONS. [OST of our readers will remember that Let us now see the appointments made by our own Board of Trade; and here we must beg to have it clearly understood that we have nothing to say personally against these tions of two as we find them stated in the public press. Mr. J. S. Pierce is well known as a railway engineer. He was a pupil of the late Mr. Brunel, worked under him for many years, and has since had charge of railways ders him "a competent person" (to quote on his own account. In what way this renthe Act) to decide the difficult and important questions which must come before him as a gas referee, it is hard to see. Another of the referees is Mr. J. H. Patterson, who is known as the author of a book on "Railway Finance," larger work on the "Science of Finance." another on the "Economy of Capital," and a We have read, too, that he has "published a treatise on the gas and water supply of London, from which the leading features of the new Gas Act have been taken;" but as we have been unable to find this work, the statement is one we have found it impossible to verify. We concede willingly, however, that Mr. Patterson has achieved a reputation as a financier; but how does that qualify him for a gas referce? When Calonne was appointed minister of finance under Louis XVI., a wit remarked that "an arithmetician was wanted, may paraphrase this by saying that, under but a dancing master got the place." We the Gas Act, "a chemist is wanted, but a financier has got the place." A practice is being introduced of reading Parliament an Act was passed, which, for rain-gauges only once a month, to enable shortness, may be cited as The City of Lonobservations to be made in places which are don Gas Act, 1868." The object of this Act difficult of access, as in the hills of Cumber- is to ensure the City of London a supply of land. Special gauges have been designed by Mr. Symons for this purpose. But, notwith-gas of the greatest possible purity, and the standing all the precautions which have been lowest possible price. Although at present highest possible illuminating power, at the taken, they have two sources of error-evapo- limited to the City of London, the provisions ration and frost. Mr. Fletcher has compared of the Act are such as may in a year or two a gauge read daily with one read monthly at be extended to the whole of the metropolis, Seathwaite, and detected a loss of 8 per cent. and be introduced into any future gas bill from the latter. Mr. Glaisher's observations that may be brought before Parliament. of a similar kind, made at Greenwich, show a loss of 6 per cent. The excess of loss in that a variety of questions remain to be Taking for granted, what is, indeed, the fact, Cumberland may fairly be set down to frost. settled, as to the degree of purity attainable Among other contingencies, snow may partly in making gas on the large scale, and as to evaporate, and thus less than the due quantity the conditions under which it must be burned when melted will run into the gauge. It is to yield the maximum of illuminating power, evident, however, that these comparisons may the Act directs that the Board of Trade shall afford an approximate correction to be ap-appoint "three competent and impartial perplied to gauges read monthly, and on this song" who shall be called "Gas Referees." account are not without value. The duties of these referees are clearly deMr. Chrimes, of Rotherham, has been ex-fined by the Act, and they are, shortly, as perimenting with tilting and inclined rain- follows:-They are to prescribe and certify gauges, kept face to the wind by means of a the mode to be adopted for testing and recordvane. Of course, these inclined gauges collect more than similar horizontal ones, the ing the illuminating power of gas; they are maximum amount being collected by that investigate the processes of manufacture carto inspect the works of the companies, and ried on therein, with the view of ascertaining the means adopted for purifying gas, and preventing nuisance, and to apply tests for ascertaining the amount of sulphur and ammonia; they are to prescribe and certify the maximum amount of impurity in each form with which the gas shall be allowed to be charged; they are to prescribe what form of apparatus shall be used for testing the illuminating power and purity of the gas; and they are to prescribe the burner to be used in testing the illuminating power. - -- -- E gauge whose aperture is kept at right angles to the falling rain. For the March showers, the tilting gauge registered a mean angle from the vertical of 69deg. 33min.; for the The third referee is Mr. John Evans, the engineer of the Chartered Gas Company. Now, the Act prescribes that of the "three competent and impartial persons" one is to be practically acquainted with the manufacture and supply of gas, and no arrangement could be more proper. It is certainly important that at least one referee should know something of the business. But last session the Chartered Company obtained extended powers under the express condition that they submitted to the conditions, inspection, and tests prescribed by the City of London Act. Thus, Mr. Evans, in the capacity of gas referee, has to prescribe the illuminating power and quality Now, to determine these points, requires, in the first place, a very complete knowledge of the chemistry of gas manufacture. To take one point, the amount of sulphur. Leaving out of the question sulphuretted hydrogen, of his own gas!! We need say nothing more, but leave our readers to form their own conclusions as to the manner in which the Government of the day is carrying into effect the intentions of the Act of Parliament which entrusted it with these appointments. THE ASHBURNHAM EXPLOSION. which, they pass through a course of practical instruction in telegraphy. They are then, if having passed a satisfactory examination, eligible for appointment in the Indian service. This second division, like the first, have received their electrical and practical telegraphic instruction under Mr. Preece, at Southampton, who has still a further number of pupils destined for the Indian service. The manufacture of the French Atlantic cable has now fairly commenced. On Monday last, the manufacture of the core was begun at the TeleTHE THE explosion which took place in the graph Construction and Maintenance Company's grounds of Ashburnham House, last gutta-percha works at the Wharf-road. PreparaFriday, while attempting to fill the " Cap-tions are being made in the Medway for mooring the tive Balloon," would hardly deserve notice "Great Eastern." When she arrives, it is intended but for the most extraordinary statements to fit her up there in a somewhat similar manner which have been made regarding it. The to what she was during the paying out in 1866. prevalence of ignorance is the favourite It is probable that as soon as her tanks are theme of newspaper writers who have, finished, and she is in a sufficiently forward state, they will begin shipping the cable, and continue recently, especially, recommended an extension of scientific education. That such doing so as it is manufactured. an extension is very desirable we gather being projected between Europe and Australia, An extension of telegraphic communication is from the account of the explosion given và Java and India. At present, Sydney is conby some of our contemporaries. The gas, nected with Bowen, in Port Denison, and the they informed us, was not hydrogen but Queensland Government are laying down a line to oxygen, its principal component being sul- Burketown, in the Bay of Carpentaria, and are inphuric acid! The intelligent reporter is tending to carry it to Cape York, close to the obviously ignorant of the fact that a balloon Torres Straits. The intermediate distance between filled with oxygen could not ascend, inasmuch India and Java has portions in course of construcas this gas is heavier than air; and he is tion, viz., from Batavia through Sumatra to Sininnocent of the knowledge that oxygen is an gapore, and a line is proposed to be constructed by element. The simple fact, no doubt, was that the Eastern Asia Telegraph Company overland to hydrogen was being generated very rapidly Malacca, to Singapore, on the completion of which Moulmein, via the Malay Peninsula, Penang and by the action of diluted sulphuric acid on zinc. East Java will be in communication with India; Whether there was any great leakage, and a this would then leave only the submarine cable to spark from the engine did set fire to the gas, Australia to be submerged to complete this extenis more than we can tell. If it were so, the sive chain of telegraphic communication. The gas ought simply to have burned and not question of telegraphic extension to Australia is produced an explosion. That hydrogen gas again being brought forward, and we have no does at times behave very strangely, we learn doubt that with the action of the press, and carefrom the account of an accident which fully directed agitation, we may soon see some happened at the works of M. Scheurer really good scheme brought forward for accomKestner, at Than, and reported by that plishing such a desirable object. An extended eminent chemist himself, and not by an ordi-line, such as would be carried out, would pass nary penny-a-liner. He was dissolving zine through so many districts, foreign and English settlements, and, in fact, touch upon so many in hydrochloric acid in a stone cistern vaulted places we have such large commercial connections over, but having a large opening for the with, that we cannot but think, a scheme fraught escape of the hydrogen evolved, when the gas with such important results cannot but be well suddenly took fire without any apparent supported by the numbers of merchants and others, cause. The flame went out as the evolution whose business will be so favourably affected by of gas decreased, and the apparatus was the successful completion of a chain of telegraphic about to be left, when a workman, contrary communication between this country and our to orders, threw in a handful of zinc. Imme-eastern and Australian settlements. diately a violent explosion took place, which did a good deal of damage. ELECTRICITY AND TELEGRAPHY. WE E learn from Paris that M. Louis, director of "Les Postes," not having complied with the conditions under which a concession for the laying of a cable from France to Algeria had been granted to him, has received notice that the said concession has become null and void. Messrs. R. S. Newall and Co. have successfully completed the cable for the Danish, Norwegian, and English Telegraph Company, between the northern coast of England and Denmark. The total length of the cable was about 340 miles, and consists of a single conducting wire throughout, insulated with india-rubber covered by Mr. Hooper's peculiar process; the cable was protected in the usual manner by hemp, and a number of iron wires as the exterior sheathing; the main cable weighed about three tons per mile, whilst the shore ends were much heavier. The screw steamers, "Archimedes " and " Chevy Chase," contained the cable, the shore ends of which On the 11th inst., the "Scanderia" left the were in the latter vessel, the main cable being Thames with the remainder of the Anglo-Medi-paid out from the former. The end was landed at Sondervig, a village near Rinkjobing, on the terranean cable for completing the direct line Danish side, and paying out was commenced from between Malta and Alexandria. The "Chiltern," the "Archimedes" on the 4th. On Sunday morning containing the first portion of the cable, arrived they sailed from the Danish coast, paying out the cable in a most successful manner, and at a very safely at Malta on the morning of the 14th. The high rate of speed, arriving in sight of the engineers and staff of the Telegraph Construction English coast on the morning of the 7th, but the and Maintenance Company engaged in this im- landing had to be deferred, owing to the temportant work have left England for the Mediter-pestuous state of the weather. However, the weather shortly moderated, and the shore end was ranean, and we hope in our next impression to be landed at Newbiggin, a village near Newcastle. able to report successful progress of the work. The splice between the cables occupied some time, Sir Charles Bright, the Anglo-Mediterranean Com-on account of the time required to make the joint pany's engineer, has also left for Malta to be prein the india-rubber, which has to be done by a sent at the laying. He has only just returned from New York. By next outward Indian mail, the second division of pupils, who have successfully passed their examination, leave for India. They have been having proper and scientific instruction given to them under the new arrangement of the Indian Telegraphic Service. After a certain examination, they undergo a severe course of study, embracing most scientific subjects, especially electricity; after peculiar process; the operation was successfully above cable, the same company are about to lay The "Narva " has arrived from New York after the recent unsuccessful attempt to lay the Cuba and Florida cable. From what information we possess, we can with confidence state that the engineers in charge and those connected with the expedition left no stone unturned to bring it to a successful issue. The cable was successfully paid out from Key West towards Havana, the "Narva" being piloted across by the U.S. steamship " Gettysburg," when Havana was well sighted in the morning, the ship appeared to have entered suddenly in a stream of great force, so much so, that for two hours but little progress was made over the ground, whilst the cable all the time was going out at a high speed; the nearest land was made for, and, owing to the current, they arrived about three miles off a village fifteen miles eastward from Chorrera, the landing place; here they ran short of cable, and buoyed the end in 800 fathoms, but the buoy broke adrift; the cable was grappled for, and caught, and buoyed, but the stream was such that the buoys would not watch. We have after numerous attempts they were unsuccessful in not space now for sufficient details, but state that bringing the end into shallower water; it now lays about four miles from the shore in 800,fathoms, and an additional length of fifteen miles of cable has been ordered, so that when the operations are resumed, the end may be lifted, the new cable spliced on, and the cable landed at the most convenient place. M. Edlund has contributed some additional in formation on the expansion of bodies by electric currents, independently of the heat produced. A ports; the extremity of one is fixed, the other is metallic wire is stretched between two supattached to a cylinder which turns round a hori zontal axis, and upon which the wire is stretched by a counterpoise. When the length of the wire varies, the cylinder turns, and with it a mirror which is fixed parallel to its axis. In this mirror was observed, with a peculiar lens, a vertically divided scale, in which was seen the displacement of the divisions were proportional to the rotation of the mirror, and consequently to the lengthening of the metallic wire. The wire was placed in the middle of a zinc case containing water, so that the temperature might be raised with or without the current. In the case of the water heated without sending a current through the wire, passing under the thread of the lens was seen a certain number of divisions n of the scale; and in measuring its electrical resistance it was found equal to a certain number of units, R. Having done so far, the water was cooled, and a current passed through the wire, and of such an intensity that the resistance of the wire was exactly R, as in the previous case. Its temperature was also exactly the same, and, besides, passing the thread of the lens was observed a number N of divisions greater than in the preceding case. The difference, M. Edlund states of N,-n is the effect produced by the curprent indendent of the heat. MR. MINING IN VICTORIA. [R. KERFERD, Minister of Mines, reports that the gold fields now extend westward from Stawell to the river Bendoc, on the eastern confines of the colony, a distance of 350 miles, and from north to south nearly 180 miles. In 1859, 125,764 miners were employed on the gold fields; in 1860 the number had fallen to 108,562, and it has continued to decrease, until in 1867 it was only 63,053 (49,036 of them alluvial miners), little more than half the number in 1859, and not quite a tithe of the population. Many have been drawn off to public works and employments of a less uncertain nature than mining. The average earnings per man per annum at the gold fields, without distinction of classes, has been increasing for the last six years, and in 1867 reached £87 1s. 7d.—viz, £67 10s. 7d. for the alluvial miners and £158 11s. 9d. for the quartz miners. The estimated value of the mining machinery in the colony is £2,079,195, larger amount of human labour was employed. The or nearly twice as much as in 1859, when a estimated value of all the claims" in the colony is £7,461,212. The gold raised in the colony to the end of 1867 was 38,910,953oz., of the value of 1,433,6870z., of which 560,527oz. were obtained £135,643,811; the gold exported in 1867 was from quartz veins and 873,160oz. from alluvial workings. The tin raised in the colony to the end of 1867 was of the value of £195,045; the silver coal, 1,938 tons, £2,899; kaolin, £7,028; flagging, £3,462; copper, £4,673; antimony, £30,426; £18,663; slates, £508; sapphires, £150; diamonds, about 80 carats, £80. IN discussing some points affecting the econo- the pintas ure son maior stam engines, while annum. upon. DISCUSSION. Mr. Bramwell said the paper read by Mr. Jones was a very comprehensive one, for it treated the subject of the manufacture of iron from the very beginning, and touched on the several modes by which it was proposed to effect economy in that manufacture. As regarded the method adopted for the utilization of the waste gases from the blast furnace, he believed we owed that to our continental neighbours. There was no doubt that those who were badly off for fuel economized more than those who were well off, and he really thought that, as far as the question of economy of fuel was concerned, the best thing that could happen to the manufacturers in the United Kingdom would be a rise in the price of * Read before the British Association. should turn their attention to some mode of making steel of a uniform quality, which would be far preferable to occasionally making some of a high and some of a low quality. The engineer and machinist wished to be able to rely absolutely on the quality of the steel he employed, and at Low Moor they were able to get a certain uniformity of quality. In the Yorkshire makes, after the puddle ball was shingled, it was beaten down into a cake, and the cake was broken into small pieces, which were then examined and sorted according to the different qualities they exhibited. This was the way in which the uniformity of the Low Moor and Bowling material was obtained. Mr. Webster, Q.C., said that he concurred with Mr. Bramwell in saying that a good invention like that of Mr. Siemens' was sure to sot others to work. He looked forward to the extensive use of this beautiful and practical invention, and had no doubt it would do more to raise the general character of our iron manufactures than anything that had been done for years. It had been pointed out that the difficulty of introducing inventions did not lie with the workmen so much as with the manufacturers. It must be acknowledged that the adoption of new inventions was not often to the interest of the manufacturers generally, because in most cases where they were dealing with the manufacture of iron they found that the abandonment of the existing machinery and the substitution of other machinery at great cost was involved. It was contrary to human nature to suppose that persons whose capital was thus involved would be the first to introduce those inventions which were being continually brought before them; and, with regard to most of those inventions, there must necessarily for a time be a contest between brains and capital. alluded to a plan by which the pig iron was not suf- facture of plates and rails up to as many as ten of the great line of rail from Paris to the MediterTHE Paris papers announce that the last section ranean, which is to connect the French frontier with Italy, will be open to the public ou October 5, from Nice to Monaco. |