THE CRACKING OF TUBES.

WHEN a piece of glass tube, sealed and filled with water, is heated, the tube is cracked in a longitudinal direction. The reason of this is said to be that glass tubes are made by taking a piece of hollow glass in a vitreous state, and pulling it at both ends. The particles of glass do not adhere to each other on all sides with equal force, but in some directions this force is stronger, in others weaker. The greatest cohesion of the particles is found, in the formed tube, parallel to the length of the tube, and the weakest cohesion in a direction perpendicular to this, This explains the cracking of the tube as stated above. In iron tubes formed in the same way, the particles of

iron are supposed to arrange themselves in a similar way to the particles in a glass tube. Hence such tubes are liable to crack under pressure in lines parallel with the tube. It may be assumed as a general principle that cleavage takes place in a direction perpendicular to the pressure

exerted.

REAPING MACHINES IN AUSTRALIA.

The machine used in Australia thrashes the ears of the corn and leaves the straw, which is afterwards cut. Mr. Ridley has recently improved the same time by a new and simple process. Mr. Ridley anticipates that in a few years' time his improved reaping machine will be universally adopted. In a short time we shall publish a full description of the improved "Ridley Reaper."

the machine, and has made it to cut the straw at

THE DIMENUON THERMOMETER.

0

MAX

120

MIN

KINIPPLE'S WATER-CLOSETS AND
FLUSHING TANKS,

MR. W. R. KINIPPLE, of Limehouse, civil engi-
neer, has just introduced "an improvement in
water-closets and in flushing-tanks or appa-
ratuses."

Fig. 1 of the accompanying engravings shows troughs B, to urinals C, and house drainage D, E the apparatus applied to water-closets A, to pipes for delivering a constant or intermittent supply of water, and F the balance float-valve appa

ratuses.

Fig. 2 is a longitudinal section of the apparatus in its most simple form. A is a chamber or box containing a hollow conical float B, which termiWilson-nates at bottom in a plug C, which, when in its seat, closes the outlet through the trap D; a is a chain or cord which the valve B is connected to a weighted lever E, the weight on which is adjustable; the upper part of the plug C is so formed and fitted that there is a space all round into the pan d, entering the float chamber 4. it to allow of water supplied through a pipe c

HITHERTO the credit of the invention and intro-
duction of the reaping machine into our own
country has been mainly awarded to Mr.
M'Cormick, a citizen of the United States. It is
now, however, our pleasing duty to notice that MR. ROBERT HENKY CAPEL WILSON,
South Australia is indebted to a countryman of st., Gray's Inn-road, has just patented "Improve-
our own, Mr. John Ridley, of Stagshaw, Northum-ments in Registering Thermometers,"
berland, who after thirteen years' residence in the
country has returned home to enjoy a well-earned
fortune. Mr. Ridley was not selfish enough to
secure the benefit of the invention to himself, but
joyfully gave it for the public good; and the
colonists, feeling that it had rendered such extra-
ordinary services, determined that some expression
of their sense of its worth should be given. A

According to this invention, in constructing a maximum and minimum thermometer the inventor limb having at its end a bulb, or enlargement, uses a tube bent into two parallel limbs, each which however is not new in itself. Into the bulb at one end of the tube a fluid, other than quick silver, but heavier than spirit, is introduced, and the inventor prefers to use diluted sulphuric acid

to the level at which the valve will be floated, the float commences to rise, the balance weight im

The action is as follows: as soon as the water rises

party of South Australian gentlemen therefore for the purpose, though other acids, or fluids mediately falls and raises the plug off its seat,

determined on presenting Mr. Ridley with a testi-
heavier than spirit, may be used so long as such
monial, in the shape of a handsome silver cande-
labrum, which they had made in Adelaide. In fluid does not act prejudicially on quicksilver or
order that the testimonial should be properly of the thermometer; beyond this a quantity of
on the tube. This constitutes the minimum end
presented, about sixty gentlemen connected with
the colony, and now resident in England, resolved quicksilver is introduced into the tube, and it is
to represent their brother colonists, and accord-preferred that the enlargement at the other, or
ingly invited Mr. Ridley to a dinner at the Albion maximum, end of the tube should also be partly
Tavern, Aldersgate-street, on Tuesday last, for the filled with the same fluid and partly with air. An
index, or pointer, is introduced into the tube on
inan, Captain Bagot, in proposing the health of constructed and filled is fixed to a scale, which is
purpose of presenting the testimonial. The Chair- either side of the quicksilver. The bent tube thus
Mr. Ridley, said the day on which they were then
assembled was very nearly the anniversary of the arranged in two horizontal lines corresponding
with the two parallel limbs of the tube of the
day when the first colonists sailed from the Thames
to found the colony of South Australia. That thermometer, and the whole is arranged in such
colony was suited for the production not only of manter as to be suspended, or supported, in a
horizontal position, the minimum limb being in
the necessaries, but the luxuries of life-corn
one horizontal plane, and the maximum limb in
another horizontal plane parallel to the maximum
limb; but it is not essential that the two limbs,

which was unrivalled in any part of the world, and the fruits of Europe and the tropics. In the year 1841, they were blessed with a most abundant harvest; but though the harvest was ripe, the labourers were few, and though every man, gentle and simple, stripped his coat and went to work, much of the crop was lost. Then it was that the inventive mind of Mr. Ridley went to work, and the result was the production of the "Ridley Reaping Machine," a model of which crowned the beautiful ornament before them.

Mr. Ridley at first met with the fate of most inventors, and his discovery was disregarded; but it was now in general use in the colony, and its benefits were acknowledged by all. Mr. Ridley gave his invention freely to the colonists, and as some recognition of the services rendered, the colonists of South Australia subscribed for and sent to this country the gift which stood before them-the work of an Australian artist. With

or parts of a thermometer should be horizontal.

By thus using dilute acid, or fluid heavier than spirit, in the bulb of a registering thermometer, the quicksilver is not liable to divide as when using spirit. It also admits of a horizontal arrangement of the tube, by which means, when the cold, the equilibrium of the quicksilver is not thermometer is subject to the greater degrees of liable to be destroyed as when the quicksilver tion is also applicable when making minimum is in a tube with two vertical limbs. This inven

thermometers.

The lower bulb and part of tube contains the dense fluid and the maximum index; mercury is introduced to move this index, and extending round the bend and partly up the other limb also moves the minimum index in upper limb; the upper bulb is filled with the dense fluid and atmospheric air. The novelty in this invention is the filling of the bulb with a dense fluid, which admits of its being placed horizontally without getting out of order.

regard to South Australia itself, it would be enough
for him to mention that in the four years 1856-9
the cereals exported amounted on the average to
£600,000, or £5 4s. per annum for each inhabi-
tant of the colony. Including their other exports
the average was £13 per head, whilst the
£136,000,000 of exports of this country gave only to fit gas apparatus in a lot of cars to be used on
A Philadelphia gentleman having made a contract
£4 14s. for each individual, calculating the popu
street railways in London, a number of wrought-iron
lation at only 28,000,000. To a colony which so cylinders have been filled with compressed gas, pre-
much depended on its agricultural productions,paratory to their being shipped to London.

whereupon the whole of the contents of the pan will be suddenly discharged and the liquid in the balance weight, suddenly falls, and the plug closes of the valve being then greater than that of the float chamber will gradually flow out; the weight the outlet. The annular space round the upper part of the plug prevents the liability of any gritty or other matter lodging and clogging the motion thereof, it also allows of the plug seat being thoroughly cleansed at each discharge.

Fig. 3 is a sectional view of a flushing apparatus. 4 is a valve rod terminating at bottom in the plug B, and at top in an eye a, whereby it is attached to an arm b of the weighted lever C. D is a hollow float free to rise and fall on the valve rod.

cc are stops against which the float abuts at the top and bottom of its course. E is a catch consisting of an upright to which is centered a crank lever, one arm of which is formed with a

nitch while the other arm is fixed to a float; the end of the lever is held in this catch until liberated by the rising of the float, whereby the notched arm of the lever catch moves outwards, thereby setting the weighted lever free to fall and raising the plug off its seat to suddenly discharge the contents of the tank. The weight of the float, float-rod, and plug being superior to

that of the weighted cover immediately restores the plug to its seat, and engages the arm in the

catch.

Fig. 4 shows the flushing apparatus employed as a liquid meter. A is the tank, the quantity which it will contain before raising the conical valve plug must first be ascertained, then, by

means of a rod connected to the weighted lever, every time the contents are flushed or let out to be registered upon an index. B is the conical float valve and plug, O the float rod connected to the crank weighted lever D and to the handle a of a cock on the inlet pipe b; c is a rod fixed to the weighted lever at one end, and communicating at the other to a registering index. It will be seen that when the weighted lever falls it not only lets out the contents of the tank, but it also shuts off the supply and moves the index rod, while on its return, due, as before explained, to the superior weight of the float-valve, it allows of

MARCH 8, 1861.]

KINIPPLE'S

FIG. 5.

the closing of the outlet, the opening of the inlet, and brings back the registering-rod.

Fig. 5 shows the apparatus for flushing sewers. 4 is the float chamber, into which liquid contents of the sewer flow through a grating B; C is a gate or flap connected to an arm of the weighted lever D, which is bell-cranked; a is an arm on the lever furnished also with an adjustable weight b. E is the catch in which the end of the arm is engaged, and F is the float whereby the catch is made to release the arm. G is the float connected to the weighted lever D; I is an outlet pipe through which liquid flows from the chamber into the sewer, and cleanses the invert of the gate or flap.

The first metropolitan street-tramway is being rapidly laid down between Bayswater and the Marble Arch. The workmen are completing no less than 200 yards a-day. We hear that it is intended to finish it by the last day of this month, and that carriages will commence running on it on the first of April next.

STEVENS'S FLOATING BOMB-PROOF | obtained was at once centered in the yard, which was

BATTERY.

For many years it has been known that there has
been in process of construction at Hoboken a floating
battery, intended for the defence of the harbour of
New York. The designer of this battery, which we
are about to describe, was the late Mr. Robert L.
Stevens, who stood high among engineers, and per-
haps did more personally for the advancement of
naval science than any one man of his day. He was
born in Hoboken in 1788, and died at the same place
in April, 1856, leaving a large number of the friends
of science to mourn his loss.

Shortly after the war of 1812, Mr. Stevens invented
a bomb which was far in advance of anything of the
kind at that time, and fully equal to any now in use.
He declined taking a patent for the invention, and the
United States Government secured the exclusive use of
it, allowing Mr. Stevens a stipend of five dollars per day
for it. Being extremely fond of the art of gunnery
he expended much time in perfecting a battery. At
Fox-hill, Hoboken, he built a target eight feet square
and tried a series of experiments upon iron plates of
various thicknesses placed compactly together. He
then arranged them with spaces between them, and
ascertained that the force of the heaviest shot could
be broken by such a disposition of iron plates, so that
without perforating more than four or five plates the
force of the ball or bomb would be entirely expended.
This series of experiments lasted for several years;
and having succeeded to his entire satisfaction in
these tests, he called the attention of the general
government to a project which he had conceived for
the construction of a mammoth floating battery for
the defence of our harbour.

The plans were so perfect, and the design so feasible-at that time we could not boast of such terrible land batteries as we have at the present, nor was our navy in a very enviable state-that, with a desire to protect this great commercial port, he was authorized to proceed with its construction. A dry dock was then commenced, suitable buildings erected, engines put up, and, in fact, every facility which could be

enclosed by a high fence, and watchmen were stationed
at convenient distances to prevent the curious_public
from looking in upon this mammoth affair. In due
time the dock was built, and all the massy machinery
put up; hundreds of tons of plate iron were brought
to the yard, and smoke rose daily from numerous
blacksmiths' forges. The keel was laid shortly after,
and for a time the work went on rapidly. Plate atter
plate was riveted to the ribs, and in about two years
the iron frame assumed the shape of a vessel. The
money which was appropriated having been expended,
a call was made upon the Government; but the war
clouds were dispelled from our horizon, and it did not
seem to our congressmen that we needed such an arti-
As their excitement waned, so did the
cle of war.
stopped, leaving a fair propor-
work, until finally
tion of a most stupendous project half finished. The
death of Mr. Stevens seemed to put a quietus on the
whole affair.

Standing on the bottom of the dock, which is formed by the solid ground, near the stern of the vessel, and looking forward towards the bow amid the forest of shores and beams which keep the hull upright, one cannot fail to be struck with the magnitude of the proposed work. It was once stated that she was 700 feet in length, with a beam of 70 feet, but had such been a true statement, she would have exceeded the famed Great Eastern in size. As far as the judgment of our reporter could be relied upon from eye measurement, she is about 400 feet in length with about 50 feet beam. Even at this figure she is the next to the largest vessel of which a keel has yet been laid. Her huge proportions rose up like a mountain of iron as seen from the bed of the basin. Her beam spreading over so much ground adds to her colossal appearance. If she were so placed upon the level of the ground where her outlining could stand in greater relief against the surrounding objects, her form would present a spectacle such as never has been witnessed on the shores of the Hudson river. Notwithstanding her great size she will draw but a light amount of water, and when completed the front of the dock and copper dam can be easily removed, and

the vessel floated out by the water, which will rush in and fill the dock where she now lies.

The hull of the vessel is built of iron plates about three-fourths of an inch in thickness, nearly eight feet in length, and about two feet in width. These are fastened together by rivets placed at about the distance of an inch and a-half from each other. The rivets below the water-line are smooth-headed, so that they will offer no resistance to the vessel's progress through the water, while those above the watermark protrude from the vessel's side over a half-inch, terminating in a sharp point. Eight is the average number of plates in depth below the water-line. The work has progressed only so far as that both forward and aft there are but two plates above the water-line, but amidships, or in the centre of the vessel, the number has increased to seven, extending only as far as the engine room. The interior of the vessel presents a very forcible impression as regards her strength. At intervals of about two feet rise up very large L-shaped bars of iron, which are the ship's ribs; two of these constitute a rib, and from the rivet holes in them it would seem that more plates are yet to be added. This is evident when we remember that she was built on the principle of having a series of plates riveted together so that spaces should intervene between each of them. The bow is very sharp, and there are good evidences that she was intended to be fortified in this locality by what is termed dead wood, but in this case it would be dead iron. Passing along aft, and on reaching the beam, or broadest part of the vessel, we find that upright stanchions or bearers have been erected. These are arranged by pairs, and are intersected by the lower deck floor beams, forming, as it were, two crosses joined at the transverse ends. These beams are built of heavy plate iron firmly united together. A portion of the deck has been laid, on which is placed her engines, which are of a novel pattern, but so dismembered that full description of them cannot be given.

The deck is below the water-line, and in all proba

the MECHANICS' MAGAZINE.

FID. The information contained in your letter has already appeared in the MECHANICS' MAGAZINE,

From the fact that our reporter had no difficulty in pursuing his investigations through the yard, and in T.B.-Nasmyth's steam hammer has been described in obtaining the minutest details of information in reference to the construction of the gigantic vessel, it is presumed that the battery will hereafter remain open for the inspection of the curious and scientific public. In consequence of the full description which we give this morning, there is now, of course, no object to be attained by preserving the secresy which has heretofore been kept so inviolate.-The World, New York, Feb. 16, 1861.

Hereafter the fee paid on a caveat will not apply as
part of the fee on application for a patent; and the
caveat will remain in force only one year, as before.

There is to be no withdrawal of money from the
office, when once paid in. The new arrangement pro-
viding for the payment of only a part of the fee on
making application for a patent, and the remainder on
its issue, superseding the old provision for withdrawing
a portion.
Additional improvements are to be done away with.
The patent for a design is to run three and a half,
seven, or fourteen years, according to the prayer of
the applicant, the fee being in proportion to the time,
as above indicated. The patent may be extended for
seven years longer, by paying the same fee, and on the
same conditions as for ordinary patents.

bility the boilers would be located on the deck beneath
it. The vessel is to be moved by two screw propellers,
the outboard entrance to the propeller alley being
about seventy feet from the rudder post. This will
be something novel in the hanging of the screw, as
braces must be used differently from any at the pre-
sent day. She will have two screws, one on each
side, and they will be submerged at all times and
under all circumstances. The keel rises up both for-
ward and aft more than in ordinary vessels. The
stern is extremely narrow, and terminates in a tri-
angled shape. The model betokens speed, while the
sides will present a very tough appearance to an
antagonist. The vessel is covered over to prevent the
unfavourable action of the weather upon it.
By a singular oversight, the bill provides for grant.
It is said when completed, there will be nine shellsing patents for designs only to American citizens, and
to such aliens as shall have resided one year in the
or plates of iron, with space between, making a wall
United States, and taken oath of their intention to be-
twenty seven inches in thickness. Being sharp at the
come citizens thereof. This clause of the bill was
bow, she can be used for cutting a vessel in two. She
added as an amendment to the original bill, and, in
was designed to carry thirty guns of the heaviest
the respect named, was copied from the old law. It
calibre on her gun deck, and mount four Paixhan is doubtless contrary to the intention and spirit of the
guns on her spar deck, and furnaces for heating red
hot shot were to be placed in different parts of the
bill, and it is to be hoped that this oversight will be
corrected before the bill shall become a law.
ship. Thus built, she would prove a valuable acqui-
sition to our harbour defences. She will have no
masts, and will probably be about 6,000 tons burden.
A number of heavy guns, with a large amount of
war material, is understood to be now on its way here
from the arsenal at Pittsburg, to be added to the ar-
mament of the battery. One hundred and fifteen tons
of shell are said to have been furnished, which are
now being brought to this city by the steam propeller
Thomas Sparks. With these additional means of
defence, the battery will be one of the most effective
and formidable defences ever constructed, and capable
of protecting any harbour from the assault of any
fleet that may be brought against it.

It is stated that over a million and a half dollars have already been expended in the construction of this battery. Of this sum about 500,000 dols. have comprised the Government appropriations, the balance having been expended by Mr. Stevens from his priPrior to Mr. Stevens's death, an additional appropriation was asked for, but was refused. Should Congress make the necessary appropriation and should a competent force of labourers be employed, it is believed that in the course of three or four months

vate resources.

the battery might be put in proper order for service. Once fully equipped the French iron frigate La Gloire and the British Warrior, likewise of iron, will be but second-rate affairs in comparison with this naval harbour defence. No fears are entertained regarding the buoyancy of the structure when completed, and this end accomplished such a tremendous weight of iron and its ramified cells, and powerful means of defence renders it perfectly invulnerable. Such was the opinion of Mr. Stevens, and scientific men who

once.

The bill sanctions the Board of Chief Examiners, which has been temporarily acting for the last three years. It consists of three examiners, whose duties are to revise the decisions of the primary examiners, on appeal from them. The routine of business under the law will be thus:-The primary examiners, they find the inventions to be new, allow the patents at If not, or if they so consider, they reject in whole, or in part, as heretofore. If the inventors adhere to their claims, they renew their oaths, and have a re-examination before the same examiners. If again rejected, they appeal to the Board of Chief Examiners, and if rejected by the Board, they have the privilege of appeal to the commissioner in person there will be the opportunity for three examinations on paying an additional fee of twenty dollars. Thus for the single application fee, and a fourth examination in the office by paying an additional fee; while the privilege of appeal beyond the Patent Office to the district judges still remains.

Models are not to be required for designs, if the invention can be clearly exhibited by drawings. In case of final rejection, models are returned to the applicant; the Commissioner, however, having the power to retain any models which it may be thought proper or desirable to preserve on record.

In all other respects of importance the old laws and practice are to remain in force. Provision is made for the appointment of additional examiners, when required by the increase of business. This is a wise provision, since the influx of foreign inventions will doubtless greatly enlarge the business of the office-perhaps double it.

.

H. G. C.-By referring to "Babbage on Machinery" you
may ascertain for yourself the correctness of the state-
ments to which you refer.

W. H.-If you will send us a description of your invention
we will inform you whether it is novel, and patentable.
C. P. B.-Your letter and drawing have been received.
Your invention is practicable, but regarding its com-
mercial value, we cannot give any decided opinion.
T. B. We shall forward your name and address to a gen-
tleman who can give you the information desired, and
supply you with an improved machine of the kind men-
tioned.

M. S.-Your communications do not contain any new in-
formation, and the first is too long for our columns. For
the information of other correspondents we publish the
latter part of your last letter:-"In consequence of my
being so great an invalid which renders me incapable from
taking any active part in carrying out my improvements,
my desire is to find out some clever and active person
who would undertake it, with whom I could confer and
make acquainted with the various improvements which
I have made upon my plan." We may state that M. S. is
the inventor of a plan of rigging vessels which is widely
known. We shall be happy to forward to M. S. any letters
received from any of our correspondents.

Received.-T. P.; G. J. G.; Tom Bowline (not authenticated); S. T.; J. L.; H. S.; A. R.

Correspondence.

THE WARRIOR.

TO THE EDITORS OF THE

66

MECHANICS' MAGAZINE.” considered as deserving the name on which I have GENTLEMEN, The principle-if indeed it may be advocated in your pages the elongation of a ship like the Warrior, in opposition to Mr. Atherton's plan of an enlargement upon the same type of form, the object in both cases being such an increase of displacement as to obtain coal power and engine power suffi cient for a longer endurance and a greater velocity, was this, that with the same midship section, the resistance encountered by the dynamic displacement of water would not then be increased, because its amount is in the ratio of the said sections; whereas, for the same reason, it would on Mr. Atherton's plan be greatly augmented. But that gentleman objected to my proposal, because he had adopted the far different principle concerning such resistance, of its being in the ratio of the static displacements, this being the necessary consequence of his erroneous interpretation of the formula namely, that "it determines I.H.P.' the mutual relations of displacement, power, and speed." I am glad, however, to find that my last communication appears to have been so far convineing that he does not now defend his plan on the ground of this false principle concerning the resistance of water. I may conclude, I suppose, from his silence on this head, that he now agrees with me that the displacing of water over distance is the point to be considered relative to its resistance; and that with mersed midship section, and not by the load displacea given velocity its amount is governed by the imment of a vessel. Well, it only remains for him now to correct his interpretation of the above formula in order to bring this friendly controversy to a close.

But no, I have deceived myself; I am not to escape scathless, for though Mr. Atherton will not defend his own principle of resistance, mine is to be met with rebuke. It is wrong, demonstrably wrong, for it leads to absurd conclusions. Ah, gentlemen, this comes of a strict mathematical training, without having received the benefit of a philosophical training to sarily are devoid of much generality, concerning the act in correction thereof. Propositions, which necescomplex affairs of the actual world, whether in its physical or its moral aspect-propositions concerning affairs complicated with cross-actings, inter-actings,

and multifarious combinations, can seldom be dealt with in the way of the argumentum ad absurdum, though, to say the truth, it is not unseldom resorted to, especially in some of the questionable parts of political economy. This argument will do very well in the abstract world of geometry and of the higher mathematics, and also in some parts of applied mathematics, as may be seen in Dr. Whewell's Mechanical Euclid;" it will do very well where axioms in the one case and inductive universal principles in the other, are the points from which deduction proceeds; but not in matters where consecutive thought emanates from principles so subordinate that they exist essentially subject to contingencies, and where consequently

the train of deduction cannot be preserved inviolate from the interruption of indirect and controlling in. fluences. It was from an educational instinct of this kind, I suppose, that Mr. Atherton has exalted my, humble practical proposition into an "ariom" forsooth, in order that he might uninterruptedly arrive at the absurdity with which he was desirous of charging it. For my part, I feel conscious of talking rather magniloquently in calling it even a principle; certainly its domain is of the narrowest: it is soon hampered with limits, within which, though correct, beyond them it is incorrect. Principles, commonly so called are indeed like a good horse, which being ridden to excess in speed or distance, breaks down into a bad one; but Mr. Atherton puts mine o mercilessly upon its metal, that he rides it to death. In this he falls into the prevalent vice of the logic of the age. The just limitation of principles effected by the qualifying influence of collateral agencies are not attended to, either by promoters or adversaries; the one class urging them beyond due bounds, and careless of what they over-ride, contend that their action is perfectly legitimate under all contingencies; the other, looking only at this ultimate and ultra-result, and regarding such a floundering about in a bog as the natural and truthful issue of these principles, adopt the converse fallacy, and with retrospective inference argue that the illegitimacy of their action extends backwards to their source and primary operations.* Persons of this class will often also, in the way of argument, push the action of a principle beyond its proper limit purposely to make it chargeable with absurdity.

a patent is the same, whatever the value of the in-
vention; whether it be a pin, a pianoforte, or a steam-
boat. I have not yet seen any attempt to construct
a "sliding scale" that would obviate either of these
difficulties, and doubt its possibility. It might be
supposed that the expense of a patent, and the great
facilities afforded for knowing what has been done by
previous patentees, would have induced more caution
than appears to be used, and that old inventions
would not often form the subject of new patents.
These circumstances do not, however, seem to have
this salutary influence, as proofs to the contrary may
be found almost weekly in your pages.

In a recent number (page 91), there is a descrip-
tion of a mode of lifting jug covers by means of a
thumb-piece, or by a weighted lever. I have a hot-
water jug in metal with a thumb-piece for lifting the
cover, certainly not made within the last twenty years;
and jugs with covers lifted by balancing levers were
shown in the great exhibition of 1851. At page 145
of your last number I notice a description of Mr.
Hewens' "recently patented" improvement in stoves,
consisting of a moveable bottom grating raised by a
rack and pinnion. Stoves constructed on this prin-
ciple have been in very extensive use for many years
past. In the year 1848, Mr. Duley, of Northampton,
patented some improvements in stoves; one of these
consisted in raising the bottom by two racks and
pinions. "I am aware," says this patentee,
moveable bottom gratings have been before used. I
do not, therefore, claim the use of moveable bottom
gratings. What I claim as new and part of my in-
vention, is the mode of raising and lowering the
bottom gratings of stoves by means of two rack bars
and pinions, as hereinbefore described."

"that

Nothing shows the recklessness of would-be pa-
tentees more than the great number of patents for
old and worthless inventions, which are applied for
but never reach maturity.
There is really very much that is not "new unler
I remain, yours respectfully,
WM. BADDELEY.

the sun."

13 Angell Terrace, Islington, March 4th, 1861.

I have just completed a new factory engine which will throw 60 gallons per minute with 10 men, 100 feet; one man can run it along on ordinary roads. Its weight, complete with 12 feet of suction and 100 feet of delivery hose, with strainer, spanners, and all the gear, being six cwt. It can be got into full work within two minutes of reaching the water; and I am quite willing to put this or my old True Blue to the gravel or any other test against the engines of any other maker.

of the land steam-engine is its untiring capabilities I quite agree with you that the greatest advantage (if it don't break down), and am sorry I cannot agree with the worthy superintendent as to the cause of its requiring such delicate handling. I don't think it is the rapidity with which the steam is generated, it is well known how to stop that, but the rapidity with which the machine is obliged to work that requires the delicate handling.

During the last year I have had eleven calls to also set fire to a brewery, but was put out before fires on the island, one being a paraffin oil works, this at tar and turpentine works, and one on board a the arrival of the Brigade-engines; two others were vessel loaded with pitch, &c., but the whole were put out without other assistance, and that without the buildings in which they originated being destroyed or seriously damaged.

So much for a powerful engine being brought quickly to bear. My engine, when fully worked, will work it at full power. Besides a powerful engine, throw 200 gallons per minute, but we seldom have to I have a brigade of 12 volunteers, as good and true as ever followed a leader, and I say this without the least disparagement to our friends the regulars, who have always met us in the most friendly manner.

I will, with your permission, take this opportunity to state my firm conviction, that if others would honour to serve, or even if two or three firms in follow the example of the gentlemen I have the manufacturing towns were to combine, or large parishes out of the London district were to provide an engine that men could be proud of there would be no lack of volunteers to form a fire-brigade, neither should we hear of so many buildings totally destroyed as we now do. I remain, Gentlemen, yours, &c., W. ROBERTS.

Millwall, March 5, 1861.

STEAM FIRE-ENGINES. GENTLEMEN,-Agreeing as I do with the greater part of your remarks in the article upon steam fireengines in last week's number of the MECHANICS' MAGAZINE, page 138, I should not have taken the liberty of trespassing upon your valuable space, but that after speaking of the gravel test, you say, "it is RAILWAY PASSENGER SIGNALS. very doubtful, however, if any steam fire-engine hitherto made would stand it, the steam fire-engine four different ways, to communicate between the GENTLEMEN,-I applied my Lady's Grenade in recently made for the Tyne Docks by Mr. Merry-passenger in a railway carriage and the guard and driver of the engine.

Now, this is what Mr. Atherton has done. My principle, that a vessel with an increase in length, but preserving the same midship section, encounters no greater resistance due to the displacement of water than before; and provided the lines are at the same time made finer to countervail the increase of resistance from friction, that it can be propelled by the same power with the same velocity as before, is one that can with great propriety be carried out to a certain point, although beyond which it would be absurd to proceed. That point is arrived at when the lines become so fine that the increase of resistance due to friction exceeds any diminution that can be procured by a further sharpness of form; and when the total friction from further extensions amidships augments the resistance until it equals that which would have resulted from an enlargement of the midship section conferring a like increase of displacement. This is an instance of that over-ruling interference by which a limit is created through the very action of the principle itself. Now, theoretically, up to that point the principle in dispute is correct; but it is needless to inquire when it is reached, for there is another point which is arrived at much sooner, and that is the prac-weather alone excepted." tical point in a shipbuilding view of the matter where despite of all our advances in constructive art the length cannot be allowed to exceed further the breadth of a vessel. Where this limit exists it is not for me, an unprofessional man, to presume to give an opinion. Perhaps no one at present is entitled to speak very confidently on the subject; in this direction as in many others, we must feel our way as we go. Now, these limits which friction and construction impose upon the principle were implied and even referred to in the terms I employed in advocating it; but it is so obvious to common sense that there must be a limit somewhere, that I might have been excused even an allusion to it, especially when my sole object was to controvert Mr. Atherton's principle of resistance. But your correspondent says, that if my "axiom," as he calls it, were "admitted as of general application," certain absurd consequences would follow. Of course they would; and the same may be said of almost any truth whatever. Wisdom resides in partial, and headlong folly in "general applications" with regard to the great bulk of the world's affairs, whether physical or moral; and therefore, as explained in preceding remarks, it is glaringly a non sequitur respecting operations within their proper limits to say, as your correspondent does, that an axiom leading to such conclusions cannot be admitted in the theory of naval architecture." I am of opinion that it is to be found there already, or it is in a much more backward state than I could have imagined.-Yours, &c.,

BENJ. CHEVERTON.

Having lately fitted two of my pumps on board the Lucy, belonging to the East and West India Dock Company, an account of which appeared in will show them to be about four times the power of No. 110 of this volume, page 73, a reference to which those for the Tyne, a greater pressure of water being obtained with 24" jet in mine than in the other with a 14" or just one-fourth the area.

I presume there is but little chance of either of those engines ever working with anything but comparatively clear water, but as my engine, True Blue, has now been in use nearly three years (and those on board the Lucy are identical in construction), and during that time have had to work in all sorts of stuff, and although we have frequently had things come through, and stop the jet, we have never had anything stop the pump through stopping in it.

At the fire at Messrs. Wright's, noticed in vol. 3, No. 55, page 26 of this Magazine, at the commence. ment we had to push the end of the suction pipe into the mud, &c., at the bottom of the ditch, there not being above 3" inches water, when we had finished there was nearly two feet of water at the end of the pipe, so that some tons of mud had gone through the engine.

1st By letting it slide down a tube on the rail where it explodes by percussion. 2nd. By throwing it from a window on the road, where it explodes by it explodes by friction, at the end of a cord, reaching percussion. 3rd. Letting it fall from a window when within a foot of the ground. 4th. By placing the grenade on the roof of a railway carriage well secured to break recoil, when it is fired by pulling a string passing into the carriage, the signal being placed within the mouth of the iron grenade after the manner that I have proposed for destroying lions, tigers, &c. &c. in my book on Projectiles.

THE action was brought by Samuel Neville against Joseph Wright for the infringement by defendant of plaintiff's patent for an invention to facilitate the annealing of glass. Mr. Temple, Q.C., Mr. Monk, At Messrs. Goodhart's fire we had as severe a test Q.C., and Mr. Hindmarch were for the plaintiff; Mr. as perhaps it was possible to have, we could not get Manisty, Q.C. and Mr. Webster for the defendant. to within 80 feet of a plug, we were in Risbie's rope The defendant first pleaded not guilty of the infringewalk at the back of the fire, among a lot of small ment, and that the patent was void: first, because it houses, the whole of the brigade engines being in was not a true and first invention; and second, front, some of these small houses being within ten because the plaintiff was not the manufacturer. Mr. feet of the flames, and the plug not being half open, Neville is the well-known glass manufacturer, and it was fully expected that they would all go, but when one of the proprietors of Messrs. Sowerby and Neville's GENTLEMEN, The proposition of your versatile the steam floats got to work, the water came down the Ellison glass-works at Gateshead. Mr. Joseph correspondent, Mr. Davies, at page 146 of your last street to us (we having made a channel for it), of course Wright is also a glass manufacturer at Forth Banks, number, to adapt the cost of a patent to the circum-bringing plenty of stones and muck of all sorts with Newcastle. The process of annealing is the means of stances of the inventor, is a novel one. It has freit, particularly every time a portion of the back walls gradually cooling glass after it has been exposed to fell down, but it did not interfere in the least with the quently been matter of complaint that the cost of working of the engine at this fire the land steam-ture, and it is an object absolutely necessary that this the greatest amount of heat necessary for its manufac This was the course which Mr. Ruskin took in his late engine could not be got to work, although the papers process should be accomplished by very slow degrees, tirade against political economy. told of the wonders it did. as if rapidly cooled, the glass would be cracked, broken,

COST OF PATENTS, AND RECKLESSNESS OF

PATENTEES.