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Ironworks, near Newport, Monmouth, it is found may be caused to take a slight retrograde motion
necessary at each stroke of the pick to give to at the time that the pick has made its stroke and
the machine a backward and forward motion. is about to return in order to make another
This has heretofore been effected, by the work- stroke, and also that the machine may be caused
man attending the machine, by the aid of a hand to make a somewhat longer forward motion
wheel. Some attempts have been previously towards the work than it has been caused to retro-
made to render the machine self-acting, but with-grade before the pick makes its next stroke.
out success. According, however, to an invention
recently patented by Mr. Jones, he renders the
machine self-acting by applying a small working
cylinder combined with the large working cylinder
which gives motion to the pick. The two ends
of the small cylinder are connected by pipes or
passages to the two ends of the large working
oylinder, so that the fluid employed (usually com-
pressed air) is supplied into the small cylinder at
the same time that it is supplied into the large
cylinder to work the pick to and fro. The piston
within the small cylinder is made in two parts to
adjust the length. On each side of the piston
there is a projection and corresponding recess in
each of the end covers of the small cylinder, in
which a ring of soft material or packing is intro-
duced. There are two piston-rods to the piston
of the small cylinder, and they respectively pass
through two stuffing-boxes made in the end
covers of the small cylinder. The outer ends of
the two piston-rods are connected to double
pauls or grip levers, which are carried by rings
fitted to the bosses or centres of the wheels of
the carriage of the machine, and by such means
the piston of the small cylinder in its to-and-fro
motion by the aid of the double pauls or grip
levers alternately gives a slight backward motion
and then a forward motion. The backward

motion takes place near the end of the stroke of the small piston, and when the pick is in the work. The piston of the small cylinder and the parts worked thereby are arranged to admit of adjustment.

Our engraving shows a side elevation, partly in section, of so much as is necessary of one of Mr. Jones's coal-cutting machines, having his

The engraving shows the arrangement as being
used for acting with a lever pick, but the same
is equally applicable when using a sliding pick
or otherwise working in a straight line. The
gearing between the small cylinder and the
wheels of the machine, and the means of supply.
ing compressed air thereto, may be varied, but
the arrangements shown in the engraving will be
found most convenient; ss is the small cylinder
in which the piston s' works; this piston is in
two parts, which are capable of being made to
come nearer together or farther from each other
by male and female screws s2. In the end covers
of this cylinder are recesses s', in which soft
material is introduced, lead with a small quantity
of tin mixed therewith being preferred. Air or
other fluid is supplied to the smaller cylinders
by the two pipes s6, s6, and it is preferred to
have the parts of the larger cylinder so arranged
that they may be closed and yet allow the air or
other fluid to pass from the passages leading to
the ports from the slide valve of the larger
cylinder to the smaller cylinder only, as by such
means the machine may be moved from place
to place by the working of the piston in the
smaller cylinder without working the piston in
the larger cylinder.

The piston-rods st, st have projecting studs
thereon, one of which enters a slotted opening s5,
in one of the nipping levers t t, which turn on
the axes v v carried by the upper parts or horns
u* of the two rings u which embrace the bosses
of the wheels of the machine; these rings will
turn or move freely on the bosses when the
nipping levers do not act on or nip the peripheries
of the bosses. The adjustment of the two parts

of the piston of the smaller cylinder to and from
each other is by the handle on the end s of one
of the piston-rods st, supposing the machine to
the larger and smaller cylinders, the pick will
be actuated by the piston in the larger cylinder,
and the piston of the smaller cylinder will by its
movement cause the machine to make a short
retrograde motion at the time when the pick is
about to be withdrawn from the work by the
piston of the larger cylinder, and the piston of
the smaller cylinder will, when the pick has been
brought back, cause the machine to advance a
distance somewhat greater than it retrograded,
and this is accomplished by means of the nipping
levers, which are stopped in one direction by a
screw pin passed into one of the two openings u
in the horns u* of the ring. The screw pins u3 are
shown in the proper positions for enab ing
the nipping levers to come into action and nip
the bosses, for the purpose of obtaining thereby
the short retrograde and the somewhat longer
advancing motion of the machine above de-
scribed; but when it is desired to move the
machine about then the positions of the screw
pins will be altered according to the direction
in which it is required to move the machine,
and they will be placed in one or the other of
the holes u u2, in the two horns u, and by
bringing the two parts of the piston of the
smaller cylinder nearer together it will by making
a longer stroke cause the bosses on the wheels
and consequently the wheels to which they are
fixed a larger extent of motion.

According to a return prepared by the Govern ment Inspector of South Durham it appears that Britain in the ten years, 1856 to 1865, the deaths from explosions of firedamp in Great Out of this number 412 occurred in South Wales, were 2,019. 340 in Yorkshire, 238 in North and East Lancashire, and 126 in South Staffordshire and Worcestershire. The total number of explosions from firedamp in Great Britain was 235 in 1856, and 377, 215, 95, 363, 119, 190, 163, 94, and 168 successively on the nine following years.

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prevent the borer from further inward motion When the pressure is excessive of course the handles are let loose and must be stopped again according to the direction and experience of the workman. The borer or tool is to be made unsymmetrical in order to prevent it from sticking fast in the bore or hole of the rock. One lap of the edge should be about two-tenths of an inch longer than the other, and therefore the diameter of the bore becomes two-tenths of an iuch larger than the diameter of the edge, so that the borer may be readily extricated even from a horizontal hole when it is turned to and fro with a suitable iron key for the purpose.

MACHINERY FOR BORING ROCKS. THE HE invention to which the accompanying engraving has reference consists of certain improvements in the construction of machinery for boring rooks, whereby the hardest rock may be pierced in the same manner as iron is bored, providing the boring tool be pressed against the rocks with sufficient force. It has been patented by Mr. S. Richards, of Crosby House, Bishopsgate, and consists of a slow-threaded screw, the head of which is made sufficiently large and solid to allow of a square recess being cut therein for the reception and holding of a boring tool. The Borew is held in position by means of a nut In the engraving, fig. 1 represents a longitudi. having a female screw thread cut therein, such nal section of the borer, constructed according to nut being fixed in a pipe or tube, the nut being the foregoing description. a is the tube; b the formed of steel and the tube of wrought iron. The screw; c the nut; and d the boring-tool-holder; end of the tube furthest from the nut and boringe the point or basis of resistance to the machine. tool is closed by a cast-iron plug somewhat in the form of a dome, or of a conical form, the surface or end of the plug being faced with steel. The plug and face are bored through for the purpose of receiving a steel pivot, the enlarged head of which projects in the rear of the machine, the diameter of the head of the pin being about

three-tenths of an inch less than the diameter of

the screw, such diameter being equal to that of the face of the plug against which the head of the pin bears. The extremity of the head of the pivot is brought to a point, and forms the basis of resistance of the machine. When it is desired to operate the borer, this pointed head must be brought to bear upon some unyielding object capable of resisting the power of the screw against the solid rock. Between the screw head containing the boring tool and the tube a steel lever is applied to the square shaft of the screw; this lever is worked by a reciprocating hand motion, the female square-cut gripper being contained in a circular rack actuated by a paul contained in the lever; it thus follows that when the machine is firmly fixed against the face of a rock and the lever is brought to bear upon the the screw will travel round out of the fixed nut from the tube and cause the boring im. plement to penetrate the rock.

вогет,

In order to prevent the tube itself from rotating during the motion of the screw four handles tab ting stays are fixed to the periphery of the tube near the plug; they are brought parallel towards the middle portion of the tube, and are then bent outwards at right angles or thereabouts, forming radii to the central line of the machine. These abutting arms are for the purpose of being controlled by the knee of the workman while he is boring, but if an excessively hard piece of rock should resist the efforts of the boring tool, and therefore cause an excessive degree of friction upon the screw threads and the face of the plug and pivot on which the tube is adjusted, then, by reason of the increase in diameter and bearing surface of the screw over that of the plug and pivot, it will follow that the tube will turn, carrying the fixed nut with it, and

Fig. 2 is the steel pivot. ff, fig. 1, show the form of the arms, handles, or stay pieces fixed to the periphery ofthe tube near the plug, for the purpose of preventing the tube from rotating. Fig. 3 is a section of the nut c; and fig. 4 a side view of the boring tool. Fig. 5 is a side view, and fig. 6 a plan view, of the lever for working the a is a steel lever; b the square cut for the gripper; c the rack; and d the paul controlled by a spring. This rack lever is applied to fig. 1 as shown at z. A brake should be applied to the machine at AA for the purpose of regulating the speed of the borer.

screw.

DESTRUCTION OF MODELS AT THE

CRYSTAL PALACE FIRE.

the late fire at the Crystal Palace, were the MONG the many works of art consumed by extensive and valuable collections of naval and engineering models placed in the galleries of the tropical department. Conspicuous among these was the model of the great suspension bridge, half a mile in length, over the River Dnieper, at Kieff, in Russia, erected about fifteen years ago by Mr. Vignoles, F.R.S., for the then emperor, at a cost of nearly half a million sterling. This model was first shown in London at the Exhibi tion of 1851, and was subsequently placed, on loan, in the Crystal Palace, where it had remained many years. It was considered a remarkable work of mechanical skill, and was constructed at an expense of several thousand pounds. The loss to Mr. Vignoles is irreparable, though a duplicate model remains in the engineering gallery at St. Petersburg, placed there by the Emperor Nicholas I., to whom it had been presented, with the imperial permission. Attached to the model was a printed descriptive account, from which the above particulars are extracted, by way of putting on record some recollection of this beautiful and singular work, destroyed, with so many other most precious and interesting objects of nature and of science, exhibited in the Crystal Palace.

ter or re-adjusted to a lathe for screw cutting. The improvement herewith illustrated is intended to save a portion of the time and labour expended in this work. It is a plate, resembling in appearance the ordinary steady rest, for which purpose it can be used. The plate A is secured to the block B by bolts passing through segmental slots in the foot C. The block is secured to the elide or carriage of the lathe, and is fed along with it. D are tool posts, which have shanks passing through the plate A, that are furnished with segmental threads similar to those on the jaws of the ordinary scroll chuck, and, like them, engaging with a scroll thread on a disc at the rear of A (not shown). E are jaw rests set by screws in the ordinary manner. The object of the improvement is to avoid the trouble of removing bolts or studs from the lathe, after being turned, for the purpose of threading them in the screwing machine, which is a quicker way than that of chasing them on the lathe, but renders them liable to be threaded one-sided. For cutting V-threads on bolts or studs, or any thread of more than four to the inch, put block B on the carriage of the lathe, and the wheels for cutting the thread required. When cutting coarse threads use three chasers or dies in the tool posts D. The dies can be cat with the hub between centres, and the dies are thus readily formed. For threading shafts of any size it is no less efficient, as will be seen at a glance. Long screws, as those intended for lathes, are kept from springing, as the rests E follow the cutters on the top of the thread and hold the work steadily and firmly to the tools. It can be used, also, for cutting down hubs on cast the practical machinist. Where the thread to be for many other purposes easily understood by or wrought work, facing and squaring up, and cut is square and fast the plate A can be set obliquely by means of the bolts and segmen. tal slots in the foot C. It has been patented through the Scientific American Patent Agency by Mr. James Wolfenden, of the Locomotive Works, Jersey City, N.J.

DYEING OF HORN.

DR. HIRSCH communicates the following to the Scientific American:-A few recipes for the dyeing of horn, especially with reference to the manufacture of buttons, or such other articles as may be exposed to the heat of boiling water, may not be out of place especially as practice has proved them to work satisfactorily. 1. Dull Black.-The buttons are boiled in a saturated solution of sugar of lead, until the colour has acquired the desired shade. According to the quality of the horu, this may take a quarter to half an hour. The buttons should then be washed with water, slightly acidulated with vinegar. 2. Irou Black.-The buttons, after being treated as stated in No. 1, are placed in a cold solution of an alkaline sulphuret. The

result is, the buttons possess a bright, metallic lustre. 3. Pearl.- After undergoing the treatment of No. 1, the buttons are brought into diluted muriatic acid, containing 3 per cent. of the strong acid. This weak solution produces, according to the duration of its influence, all shades, from the darkest blackish blue to the lightest white. 4. Silver-Gray.-The buttons from No. 1 are placed in a solution of nitrate of mercury, saturated at a temperature of 140 degs.-170 degs. Fah. The treatment in this bath should last ten to twenty minutes, which, if cleanliness be observed, will produce most elegant results. 5. Chocolate Brown-The buttons from No. 4 are boiled for about a quarter of an hour in a concentrated but thin solution of catechu. 6. Chocolate Brown, Dark. The buttons from No. 5 are placed in a warm bath of bicarbonate of potash, containing 3 per cent. of the salt. With the duration of the treatment the colour darkens. 7. Chocolate Brown.-The but tons of No. 5 are placed in a warm solution of sugar of lead, saturated at the common temperature. This colour looks especially well in knife handles, etc. 8. Bronze Brown. The buttons from No. 4 are placed in a solution of esculine (the pigment of the horse chesnut), and treated and boiled as in No. 5. 9. Bronze Brown.-The buttons from No. 4 are boiled for quarter of an hour in a concentrated solution of green vitriol, and then in æsculine. The resulting bronze differs materially from the former, possessing great softness. 10. Light Brown.-The buttons from No. 4 are boiled in a solution of galls or pure tannin. This is especially adapted to netty designs, to which it imparts a silky luster. Upon the sensitive surface, produced by treatment No. 4, a great many combinations of colours may be produced.

A

founded are at present mainly empirical, then
it may be replied that in the early stages of every
science its rules are mainly empirical; but it has
never before been urged that, therefore, we ought
to deprive ourselves of such advantages as may
be derived from the limited amount of knowledge
we may happen to possess.

have any sensible influence on the empirical laws upon which storm warnings have been based. The truth is, this land meteorology scheme is altogether unnecessary for the purpose of correcting these empirical laws. It is not so much in the multiplication of observations over limited areas, as in the adoption of improved methods of combining and treating observations at stations scattered some distance apart over every accessi. ble portion of the earth's surface, that we must look for new discoveries, and for the means of establishing the rules of meteorology on a strictly scientific basis.

The rules by which the laws of magnetism are applied to the correction of compasses in iron ships are to a great extent empirical, and, in spite of the greatest care in their application, serious errors are sometimes made; but are we on that account to decline to avail ourselves of such aid as they do afford, imperfect, and to some extent The cost of carrying out the land meteorology uncertain, though it may be? Long after the scheme would be out of all proportion to the predicted places of the moon were given in the results ever likely to be obtained from it; and it "Nautical Almanac," the longitudes derived from would be unjust to the commercial community lunar distances were often very considerably in to withdraw the funds which have hitherto been error, but no scientific man, or body of men, at so usefully applied in the interests of humanity that time ventured to suggest that the publication and commerce, and devote them to the establish. of the "Nautical Almanac" ought to be suspended ment, by an irresponsible body, of a scheme of until astronomers had perfected the lunar theory. such doubtful utility. It will be evident from The laws relating to the strength of materials the above remarks that the recommendation of were long in a very unsatisfactory state; but the president and council of the Royal Society, scientific men did not urge that, therefore, we from whatever point of view it may be regarded, ought to suspend building and engineering is a retrograde movement, opposed to the true operations until these laws had been established interests of the science of meteorology, and on a strictly scientific basis. It is needless, likely, if acted upon, to retard its progress. It however, to multiply illustrations to show the is therefore to be hoped that the Board of Trade unsoundness of the principle on which the recom- will reconsider their decision, and not, for light mendation is based; and it requires but a and insufficient reasons, discontinue a system moderate acquaintance with scientific methods which, on grounds of humanity and commercial to see that in a science which aims at prediction, economy, has met with the general approval of its progress will be best and most surely advanced the country, and is, moreover, so likely to con by a continuous and systematic comparison tribute materially to the advancement of a of the phenomena as they actually occur with the popular and highly-important branch of science. phenomena as predicted. It is in this way that Mr. Thomas Heelis, F.R.A.S., urged that the the methods of astronomy have attained their abolition of the cautionary signals would tell present high degree of perfection; and it will be hardly against the coasting craft and fishermen. obvious, on a little consideration, that, if Mr. To large well-found sea-going vessels, welBabington's predictions or forecasts of the provided with instruments, the signals were not weather are regularly and systematically com- of much use, but the case was very different with pared with the phenomena which actually occur, the masters and owners of the coasting vessels instanced the case of the colliers which supply the large steamers at Southampton with coal brought from the south Welsh ports. These vessels have to make all their passages from Southampton to the westward in ballast, and it is of the utmost importance to them not to be caught by a gale from the southward between Plymouth or Falmouth and the Land's End. He was not aware that any complaints as to the inefficiency of the storm warnings had been received from the masters of coasters, and con sidering the amount of capital and number of hands employed in the trade, and the fact that they had no powerful organ to advocate their views, he thought that their interests deserved consideration, and feared that they had been overlooked. The saving of life should, especially at present when so mary complaints are current about the deficiency in the supply of seamen, be a great object, even if such saving were effected by empirical means. Mr. Heelis had no confi dence in the prospect of improving the me teorology of the coast by observations inland. He rather advocated the improvement of the land meteorology by observations on the coast; and he had noticed a decided improvement of late in the storm warnings. Having been engaged in a yachting cruise on the Cornish coast during the months of August and September last, he had paid a good deal of attention to the signals, and had never seen them hoisted without the forecast being speedily verified.

In the circular issued by the Board of Trade

"" to

SUSPENSION OF STORM SIGNALS. Tan ordinary meeting of the Manchester December 11, 1866, Edward Schunck, Ph.D., less often be brought under immediate notice F.R.S., &c., president, in the chair, Mr. Joseph which might otherwise long escape detection, and Baxendall, FR. S., read the following paper: in this way an impetus will be given to the pro"On the Recent Suspension, by the Board of gress of the science which could not be applied Trade, of Cautionary Storm Warnings:"-On in any other way, or by any other means. the 29th ult., a circular was issued by the Board of Trade, announcing that the cautionary it is stated that the president and council of the storm warnings," which have from time to time Royal Society think that "in a few years the been issued by the meteorological department of rules on which storm warnings are founded may the board, would be suspended from the 7th day probably be much improved by deductions from of December instant. This step, it appears, has the observations in land meteorology, which will been taken on the recommendation of the presi- by that time have been collected and studied." dent and council of the Royal Society, who are Now, this allusion to land meteorology refers, no of opinion that "at present these warnings are doubt, to a recommendation made in a letter founded on rules mainly empirical, and there- addressed by the president of the Royal Society fore should not be issued under the superintend- to Mr. Farrer, one of the secretaries of the ence of the scientific body to whom the discussion Board of Trade, on the 15th June, 1865. Mr. of meteorological observations will be com- Farrer had informed the president "that the mitted." No attempt appears to have been Admiralty were willing to undertake, and to made by the board to ascertain the opinions and place in the hands of their hydrographer, all wishes of those classes of the community for those observations which can properly be made whose benefit the system of issuing storm warn- use of in framing charts for purposes of naviings was originated by the late Admiral Fitzroy. gation, but not those which relate to meteorology No complaints against the system, as carried out proper;" and the president, in referring to this, by the admiral, and since his death by Mr. interprets the term "meteorology proper Babington, have been made by those most deeply mean merely "the land meteorology of the interested in its operation; nor has any evidence British Islands;" but how this singular interbeen produced to show that it has led to loss or in-pretation was arrived at is not stated. He then convenience. On the contrary, it is very gene- goes on to urge the desirability of establishing rally admitted that it has been the means of a few stations-say six-distributed at nearly saving many valuable lives, and also an amount equal distances, in a meridianal direction, from of property greatly exceeding in value the whole the scuth of England to the north of Scotland, cost of the department in which it had its origin. furnished with self-recording instruments, supWhether the rules on which it is founded are plied from, and duly verified at, one of the empirical or not, the system, as a mere commer-stations, regarded as a central station." This cial speculation, has been successful, and it is central station he afterwards suggests should be therefore difficult to understand why the Board the observatory of the British Association, at of Trade should have attached so much import- Kew. Now, it has long been known to meteoroloance to the reasons advanced by the president gists that deductions from observations made and council of the Royal Society, and allowed them to outweigh other far more important coneiderations. If the president and council think that the superintendence of the duties connected with the system of issuing storm warnings would be derogatory to the scientific body to whom the discussion of meteorological observations will be committed, it does not follow that the system ought to be suspended for an indefinite length of time, but rather, that its management ought to be committed to some more suitably constituted body. If, however, it is intended to be understood that the system ought to be discontinued because the rules upon which storm warnings are

within the narrow limits of the British Islands
are quite insufficient to lead to the detection
and development of the laws which regulate
those great movements and phenomena of the
atmosphere upon which the daily changes in the
weather at any given station depend. The
principal meteorological elements of the British
Islands have already been determined with con-
siderable accuracy, from observations made
during long series of years, at various observa-
tories and stations, both public and private; and
any minute changes in their values that may be
rendered necessary by future observations with
improved instruments are not at all likely to

THE OCEAN CURRENTS. PROFESSOR Tema of upon the subject of DROFESSOR GRIMES, of Philadelphia, made the Ocean Currents, at a recent meeting of the American Institute-Polytechnic Branch, the president, Professor Tillman, being in the chair: Columbus, during his first voyage, discovered in the midst of the ocean an immense stream moving with great velocity and superior in its proportions to the largest continental river known. Since the announcement of the exist ence of this, the Gulf Stream, similar currents have been traced, both in the Pacific and Indian Oceans, and now physicists recognise five, one each in the North and South Atlantic and Pacific, the remaining one in the Indian Ocean. The six continents of the world are arranged in pairs, as a glance at any map will show. Hence, from this and many other points of similarity, it is

evident that whatever force caused the one repeated itself in forming the others. The hypothesis advanced by Professor Grimes refers the question back to the age when the entire earth was covered with water, at which time six elliptical currents were formed. Five now remain; the sixth one was formed in the North Indian, an ocean which, owing to the elevation of land, no longer exists, but the Caspian and Aral seas, and the large lakes of Asia furnish proof of its former reality. By a simple mechanical problem we can demonstrate why these ellipses were formed. If bear the edge of a disc revolving rapidly on its centre a ball is placed, and caused by any means to pass alternately back and forth on the radius, its motion will not be in a straight line, but it will invariably traverse an ellipse. To make an application: when the waters in the Gulf of Mexico have become heated by the sun, the tendency will be to pass north until cooled, then to return to the equator, and such would be the only motion

were the earth at rest; but the revolution of the earth is a constant force acting upon the current of water and gradually overcoming this northernly motion, and turning it to the east, by the coast of Ireland. Becoming cool, it seeks the warmer regions, and the easting is transferred into a general southernly direction, but, as it nears the coast of Africa, its velocity is lost, and as the earth moves more rapidly than the current, the latter is left behind, or is giving an apparent westward motion, till the Gulf of Mexico is again reached and the circle is completed. During the Creation the land appeared on the margin of, and between, the circles; in proof of which the pointing of the three southern continents to the south-east-features first pointed out by Humboldt-the accumulation of lands toward the north, rather than the south, and the direction of the glacial markings during the drift period-these all bear witness to and are explained by this theory.

Legal Intelligence.

UNITED STATES CIRCUIT COURT, SOUTHERN DIVISION. Before JUDGE NELSON. DECISION IN THE PARROTT GUN CASE.* The bill is filed by Treadwell against Parrott, maker of the well-known Parrott gun, founded on letters patent granted Dec. 11, 1855, and reissued Feb. 4, 1862, for improvement in the manufacture of cannon, to restrain him from infringement. The invention claims, first, casting a cannon the walls of which are encased with wrought-iron rings, smaller than the part which they are to surround but enlarged by expansion, and by contraction bringing the particles of said body nearer together. Second, in securing the hoops, a female screw is cut on the inside to fit threads cut on the body of the gun, and are finished to 1-1000th part of the interior diameters less than the male screw to be encircled. The Barlow Law, to which the inventor refers as having furnished him with the principles leading to this invention, showed that "hollow cylinders of the same material, do not increase in strength in the ratio of increased thickness, but the power of resistance diminishes after considerable thickness is obtained." To obviate the elements of weakness caused as above, and to obtain the strength of wrought instead of cast iron, the plan of construction before described is resorted to, and by this means a gun is made nearly four times stronger than a cast-iron gun of the same weight.

The only material and difficult question is, whether or not the patentee is the original and first inventor of the improvement. After an attentive examination, and our best consideration, the conclusion seems clear that he is not.

A combined cast-iron gun and wrought iron envelope was constructed by Thiery, a French of ficer, as early as 1834. It is seen from his description that the hooping of cast-iron guns by wrought-iron bands, much after the manner of the patentee, was then known to add to the power of resistance; that this was increased by the contraction of heated bands; and the difference in diameter was governed by the law of expansion of wrought iron.

* Reported in the Scientific American.

In 1843, the Frith gun was patented in England, having a cast-iron barrel, that part most acted upon by the explosion being strengthened by strong wrought-iron or steel bands, driven on while hot, so that the contraction thereof in cooling would produce firm adhesion. The question might here arise, whether the information in the description would enable an intelligent mechanic to make the proper difference between the interior diameter of the hoop and the exterior diameter of the guns body. We are assured that anyone having any knowledge in relation to this subject is qualified to carry into effect in a scientific way the purpose and object of the patentee. This is also affirmed in detail by all the defendant's experts, whose attention was called to the subject. The state of the art was familiar to Chambers in 1849, for by his own statements he determined the difference in diameter of the wrought-iron hoops used in his wrought-iron guns of that date, on the principle of the law of expansion of wrought thickness of the walls of the Frith gun nearly iron. Another point should be noticed. The correspond with the thickness of complainant's, and the same is true as to thickness of the hoops. Whether or not this inventor has a knowledge of Barlow's Law, cannot affect the question.

The point of superiority of finish of the defend. ant's cannon over the old Frith gun is not en titled to consideration. It is owing to the mechanic and not the inventor. Upon the whole, without pursuing the case further, we are compelled to the conclusion: That in view of the state of the art at the time, the improvement in the construction of cast-iron guns with wroughtiron hoops, claimed by the complainant, will be found in a description of the Frith patent, and upon this ground a decree must be entered for the defendant, dismissing the bill.

Correspondence.

GAS REVERBERATORY FURNACES. TO THE EDITOR OF THE "MECHANICS' MAGAZINE." SIR, I gather from reading your article and description of the method of working the Silesian Gas Furnace, in No. 2,198 of the MECHANICS' MAGAZINE, that it is used as a substitute for the common reverberatory furnace in which iron is melted for casting purposes, and also as a sub. stitute for the refinery, as used in this country, for making "plate iron" or "refined metal." I do not clearly learn whether or not the side tuyeres are used at Königshütte when iron is melted to be run direct into gun moulds, or only when iron is to be refined for again melting in mixture with other irons, and then run into moulds without any blowing. In the description of the method of working the Silesian gas furnace, it is stated that the "furnace may be employed with or without the two lateral tuyeres; these are introduced when it is to be used as a refinery furnace; but, under any circumstances, their judicious employment must facilitate the rapid mixture and purification of the metal, the objects to be attained in the remelting of iron for important difference in the results obtained by simply melting, and by melting and blowing combined. When iron is melted in a common reverberatory furnace, and kept in a molten state for some time, more or less carbon is eliminated; the quantity chiefly depending upon the greater or less time the iron is exposed to an oxidising flame. During the process some iron is also oxidised, most of it passing into the slag, and some into flue dust. The percentage of sulphur is increased during the operation, sulphur being absorbed from the gas flame and dust from the fire. Also it is probable that, although some of the iron treated is oxidised, none of the sulphur it originally contained becomes oxidised, and, consequently, the percentage of sulphur is in creased by this concentration of the iron. The same is probable of the phosphorus, which is likely to have its percentage increased to a slight extent by the diminution of the weight of iron. The effect of this concentration upon any silicon originally in the pig iron is, perhaps, more doubtful, as some of it may combine, as silica, with the oxide of iron developed, and pass off in the slag. Carefully made analyses of any iron treated in an air furnace, before and after melting, and of the slag produced, would be very

the manufacture of ordnance." Now there is an

interesting; and I should be glad if any of your correspondents could inform me as to where I could get access to such, if published.

In the common refinery for "plate iron" or "refined metal," which generally has six blowdown tuyeres, the iron treated is decarbonised to a considerable extent; but what appears to be of greater importance is, that the resulting "plateiron contains generally 60 to 90 per cent. less silicon, and 25 to 50 per cent. less sulphur, than the pig iron from which it was produced. It does not appear that the partial decorbonisation effected in the refinery benefits the ironmaster, as far as the cost of the subsequent process, puddling (when such " plate-iron" is practically totally decarbonised) is concerned; as a higher price is paid the puddler for convert. ing it than for common white iron, which con. tains more carbon. There is the advantage of a better puddling furnace yield as a partial set-off against the waste in the refinery, and a better the ordnance iron at Königshütte, when finally melted. Were it blown into, I do not think the melted for the moulds, is blown into, but only results would be so uniform as is claimed, for it would be difficult to turn off the blast at precisely the same stage of refinement in two consecutive meltings; nor is it likely that they find iron approaching plate-iron in character so adaptable for guns as a mixture of iron simply melted and kept in that state for some time, or iron so melted three or four times in succession before casting; the latter method having been proved by Mr. Fairbairn to greatly increase the strength of cast iron.

quality of bar produced. I do not expect that

The removal of sulphur from ordnance iron does not appear to be desirable for increasing its strength. In the ordnance produced at Finspong, cast direct from a charcoal blast furnace, there is a good percentage of sulphur; and in the specimens of Finspong gun iron exhibited in the Stockholm Exhibition, the sulphur appeared to have assumed a distinct network form, with the graphitic iron in the meshes, instead of the mottled form (when it arises from sulphur) so common in this country. It would be of great interest to your readers if anyone could favour them with the chemical composition of the several pig irons used at Königshütte, and of the iron There is abunand slag produced from them. dant room for improvement in the refining ap. paratus in common use in this country; and as at many works the iron is refined before puddling for the production of best quality plates and bars, and at other works for the sale of refined metal for casting purposes, &c., the capabilities of Eck's and Siemens's arrangements to reduce the cost of refining should command the attention of iron refiners. The great saving is in fuel. In the commcn refinery, at least four out of the six tuyeres are-or, at least, two-thirds of the work of each is-required for the combustion of the fuel for melting down the charge, or for keeping it molten if charged in that condition; while only the other one-third, or less, of the blast is used for oxidising some of the carbon, sulphur, and silicon in the iron. Also from the position of the fuel and recoil of the blast, possibly not less than two-thirds of the heating power of the fuel used is blown up the stack, and so lost.

waste of fuel in the refinery, and waste of power Mr. G. Parry, of Ebbw Vale, observing this in producing two-thirds more blast than was utilised in refining properly so called, adopted a modification of the common reverberatory furnace, and of Eck's refinery combined, for refining. Mr. Parry's improved refinery consists of a reverberatory furnace with a bridge much higher than commonly used, and having two side tuyeres in the body of the furnace, as in Eck's. Mr. Parry's refinery has a stack 50ft, high, which, by its draught, produces combustion of the fuel, instead of four out of the six blow-down tuyeres of the common refinery; thereby saving the power required for providing them with blast. The fuel used is coal instead of the more expensive coke required for the old plan. The new furnace has also the advantage of keeping the inorganic elements of the fuel well separated from the iron to be refined. The high bridge and modified furnace roof cause all the flames to impinge on the iron, and in actual work this furnace has refined iron with a saving of two-thirds of the fuel generally used. Mr. Parry introduced another improvement, which was the sending of super. heated steam through a third side tuyere into the molten iron. He says that steam for refining has been successfully used in this furnace, both

as to the operation and result, the iron retaining its fluidity for a sufficient time, and becoming desulphurised to a great extent; but what perhaps most enhances the value of the steaming process is its effect upon the forge cinder used in the refining process. This cinder is desulphurised and dephosphorised to a very considerable extent, and thus very greatly improved for using, as an ore, in the blast furnace again. It is surprising that this arrangement of Mr. Parry's has not found greater favour among refiners of iron. It is an improvement upon the old method, even without the steaming detail.

perfect melting or refining furnace is required by
the Government at Woolwich, they should put
down a Siemens's furnace in preference to Eck's.
They have capital enough, and in a short time the
difference in the first cost would be made up, and
a saving ever afterwards ensured. I hope Mr.
Siemens's royalty has not been so adjusted as, in
the eyes of the Government, to balance the differ-
ence in economy of his over Eck's. There being
no patent-right for Eck's is not a little advantage
in the eyes of ironmakers, who always detest
patent royalties.
I am, Sir, yours, &c.,

and lungs get filled with dust. A gas furnace for
heating rail piles was some time ago built and
experimented upon at the Ebbw Vale Works;
but through a fault in its design a welding heat
could never be got up on the bed of the furnace.
The supply of air was also badly regulated, since
at one point, between the generator and furnace
bridge, the bricks of an arch were melted like
water; showing plenty of heating power, but
developed at the wrong point. During the ex-
periments the piles remained in the furnace
from twelve to twenty-four hours at a time, and,
to the astonishment of the workmen, the piles
when withdrawn were as perfect on their edges,
and weighed as much, as when charged. This
was a pleasing fact for the mill manager, could
he have brought the piles out to the rolls. After
several attempts, I believe the expectation of THE VERMICULOUS MOTION OF RAILWAY
success was given up, and the furnace stands
idle. Coke was the fuel used.

It can, however, be readily believed that, setting the steaming process aside, Eck's refinery is a more perfect arrangement than Parry's. There must be a more perfect, and therefore more profitable, oxidation of the fuel at the starting point, since with a generator of sufficient height and capacity only carbonic oxide gas goes over the bridge; while in Parry's not a small quantity At the Sandviken Bessemer Steel Works, beof carbonic acid gas goes over, and even raw air longing to the Högbo Steel and Iron Company, I saw as well, when, as occasionally happens, there is gas furnaces for heating 45in. square steel ingots for a hole in the grate. I should expect that all the hammering down for guns. These furnaces had carbonic oxide which goes over the bridge of two generators each, one at either end, with Parry's refinery is completely oxidised by the flues going down through the bed of the furnace, blast tuyeres, and utilised over the furnace bed. and leading off to the steam boilers. These fur. Mr. Cox, in a letter which appeared in No. naces are very compact, and do not occupy so 2,199 of the MECHANICS' MAGAZINE, says that much room as one would expect. They were not Eck's furnace requires the laying down of blowing at work when I saw them, but Mr. Göransen, the engines and boilers. This could not be urged as an manager, assured me they gave perfect satisfacobjection when it is to be substituted for the old tion: one of the best features being that when refineries, as they are often so near to blast fur- the door was raised for examining or withdraw. naces as to receive their charges in a molten ing the ingot no raw air went in to oxidise the state from them, and so are easily supplied with steel, but gas flames came out instead. The fuel blast from the furnace mains; and where re-used in these furnaces was coal from the Shire fineries are at present used for melting down cold Oaks Colliery, shipped at Grimsby. Mr. Göransen pig, as at tin-plate works, and forges making for stated that Shire Oak coal was hard, and the best bar and plate mills, there are already blowing they could get for the purpose. With such an arrangements; and in every case less blast would example as these Sandviken furnaces, what is to be required for Eck's than for the present method. prevent the adoption of gas heating furnaces in I think Mr. Cox will also find that in several our mills, and the using of moderately bituminous forges and mills there are blowing arrangements coal in them? for urging the fires of puddling and heating fur- Speaking of Eck's generator, Mr. Cox says:naces. These same arrangements could be "It must result that at times there is an excess readily adapted for supplying Eck's generators. of oxygen in the furnace, which must oxidise Reverberatory furnaces for simply melting, known and waste the charge, and at other times there is as "air" or "wind" furnaces, are to be found at an excess of gas." In your account of the every foundry and casting establishment. At the method of working the Silesian furnace, you say same places cupolas and their blowing arrange- the generators are always kept full of fuel, a ments are to be found. At such places the con- condition easy to ensure, considering the small version of the air furnaces and supply of blast quantity to be charged in an hour. With this would be very simple matters, and very profit- condition fulfilled, I do not think the composition able to the proprietors. Four pounds per inch or the supply of the gases would be variable blast pressure, as used for Eck's at Königshütte, enough to interfere with the regular working of if for the generators, appears excessive, and, the furnace. Carbonic oxide would always be indeed, injurious; for such a pressure must drive the predominating gas, and of regular supply. dust and ashes over the bridge. Ordinary fan As to oxygen in the furnace (free, or raw air, I blast is quite strong enough; and to get in the presume), I do not see how, under the condi. requisite volume of blast larger tuyeres should be tions, that could possibly get into the furnace. used. With low pressures less power is required Then, again, is it likely that the variation of to send the same volume of air into the gene-intensity in Eck's, if the supply of blast were un

rators.

attended to, would be greater than when a fresh On passing many forges and mills, one cannot regenerator is turned on to Siemens's furnace, help noticing the volumes of smoke emitted by supposing the supply of gas and blast to be the furnace stacks; and the accompanying flames similarly unattended to in Siemens's as well? illuminate, at night-time, an entire neighbour. The fact is, both furnaces must be attended to hood. If such furnaces are inspected, the necks and regulated; but happily that is not a difficult are seen to be full of flame, and higher up in the task with either of them. There is no doubt but stacks, at the cracks here and there, their inte- that with a generator as high as practicable, and riors are seen to be intensely heated. Now all this of a good capacity, gas of a very uniform quality heat from the commencement of the furnace neck, and quantity would be produced in Eck's. excepting the small portion of it necessary to Siemens's furnace has decidedly an advantage produce draught, is, of course, entire loss. At over Eck's in the matter of stopping for cleaning the more modern forges and mills, the necks are out. "Lighting coal" is not an inconsiderable turned into underground flues, and the waste heat item in the cost at forges and mills at present, is thereby conveyed to boilers for generating but I believe the quantity requisite to "light" steam. This, by utilising the surplus heat, is a one of Eck's would be very much less than is step in the right direction; but, after all, we have now used with common furnaces, simply because the pain of knowing that imperfect combustion a more complete combustion is effected, and an and loss of fuel goes on as before in the furnace inferior fuel can be used after the first layer is grates, and also of enduring occasional bad yields well lighted. The fact that inferior fuel can be from burnt iron, both in puddling and heating used in Siemens's and Eck's furnaces, with quite furnaces. For practising the greatest economy as good heating results as best fuel can produce in fuel in forges and mills, whether of old or new (though necessarily with a greater quantity of arrangement, where there is already any blow- the former) is a point in favour of both. How ing apparatus, and with least cost of conversion, often is a forge or mill manager compelled to Eck's furnaces should be adopted; and where place the fault of a week's bad yields or small there are underground flues leading to steam make against the coal supplied? And the same boilers the surplus heat would be utilised nearly with the forge and mill men to their masters; as efficiently as in Siemen's regenerators. bad coal-no knobs-stony-dusty-dirty-clinSiemens's arrangement should, no doubt, bekery coal, is their constant refuge and excuse for adopted where any works entirely new are to be put down, as being the most perfect in its action, and most cleanly and comfortable for all concerned. Only those who have bad to exist in forges and mills can estimate the boon of having no coal and ashes-fillers working close by, especially in windy weather, when everyone's eyes

Brendon Hill Mines,
Taunton, Jan. 1, 1867.

TRAINS.

THOMAS MORGANS.

ticle on this subject, and as I constantly travel on a
SIR,-I have read with great interest your ar
line that is painfully subject to this motion with its
express trains, I wish to say a few words about it.
I really do not think that the engine is at fault,
excepting insomuch as it is frequently driven at ex-
cessive speed, and I maintain that the speed is the
true cause of the rocking. A train timed to run at
40 miles an hour, on the rail I am writing about,
rides easily enough; delay it, and try to make up
the time at 50 or 60 miles, and you cannot sit in
your seat. This sort of running I do not cousider
safe, more especially on a line of stiff gradients
and curves. Depend upon it, Sir, this is the main
point;
all others mentioned in your article are ac.
cessories no doubt, and I would mention one other
point, the closeness of the wheels of the carriages.
On one occasion I was so incommoded, not to say
frightened, that after trying to couple up the car.
riages, but with no result, I changed from a first to
a second class carriage, and instantly got relief
though the pace was the same, but I found that the
second class carriage was longer and the wheels
farther apart. This is, I think, a great point and
was so in the coaching times. The last style of mail
coach was longer between the wheels, and you
could gallop the team with little or no rocking.
On the North-Western line the wheels are very far
apart, and I rarely find any oscillation, even at a
speed beyond that I have already mentiond on
another line. It must also be borne in mind, at
not get this motion on the old main lines, it is on
least so my experience goes to prove, that you do
lines of a later date that it occurs; constructed pro-
bably at first cost cheaper, with heavy gradients
and sharp curves, but surely telling a tale in
working expenses in the long run. This I will il-
lustrate by an often-repeated trial on a branch of
one of our leading railways where no sooner do
you join the main line than all this disagreeable
motion ceases, bearing in mind that the speed is
even greater on the main line than on the branch.
I am, Sir, yours, &c.,

OBSERVER.

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Thursday evening.

We must absolutely decline attending to communiontions unaccompanied by the name and address of the writer, not necessarily for insertion, but as a proof of good faith.-ED. M. M.

RECEIVED.-J. E. P.-R. L.-T. M.-C. D. A.-D. G. F.
-G. E. P.-A. W.-J. O. E.-G. E. P.-G. S. L.-A. B. B.
W. Bros.-M. R. and Co.-T. Bros.-W. W.-P. and C.-
-J. B. H.-J. H.-Sir J, C.-J. E. P.-J. H. W.-
J. M'G.

information upon cotton culture and manufacture in Dr.
REGGENOH (Cardiff).-You will find a vast amount of
Ures's Dictionary of Arts and Sciences, or in Tomlinson's
Cyclopedia of Arts and Manufactures. The printed specif

cations at the Patent Office also afford much information
upon every description of cotton machinery.

The Lords of the Admiralty have given direc tions for three new vessels to be laid down at Chatham Dockyard as soon as the work now in bad work. We are not to forget one minor ad- progress at that establishment will allow of their vantage of Eck's furnace over Siemens's. During two of the improved corvette class, together with being commenced. The vessels ordered include the regular working of Siemens's there is a constant loss of heat between the generators and the tended to build one or more composite gunboats of a double screw gun vessel, it being likewise in furnaces, which is avoided in Eck's, as the gene-iron and wood, and each of about 500 tons burden. rator is close to the combustion poiut. The vessels ordered will be laid down on the vacant Before concluding, I would remark that, if a slips early in the ensuing year.

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