wind-mill; and was used for that purpose in Kent, some time before my
departure for France, in 1792. It is founded on the doctrine of opposite
qualities--and is a practical combat between equal and unequal motions.
In wind-mills, the mechanism is exposed to all the variations of a
capricious element: and the common way of preventing these convulsive
motions from injuring the _flour_, was for a man to attend a lever
connected with the _bridge tree_, (which carries the upper stone) and by
it to bring the stones nearer together when the wind was strong--and
nearer still, when it was violent: and, contrariwise, to lift again the
upper stone when the wind assumed a milder movement. A process this,
which _nearly_ equalizes the degree of grinding, but not so nearly the
quality of the meal--for this is found to be more heated by great, than
by moderate velocities. At all events I thought a Machine like the
present, would regulate this process, as well as a man; and it was found
to do so--except, perhaps, in very extreme cases.
This Governor, is represented in fig. 1 of Plate 27--the ground work of
which is the same as that of the third figure in Plate 3: for in reality
the present Machine claims the precedence of the Dynamometer; and may
therefore, well borrow a figure from it’s description. _A_ is the
power-axis, receiving motion from any proper shaft of the mill. It is
turned _backward_ by that shaft, and therefore tends to raise the ball
_B_--an operation equivalent to bringing the mill-stones nearer
together. At the same time, the axis of resistance _C_, carries round a
pallet-wheel _D E_, and by the pallet _D_, sets the pendulum _F G_ a
vibrating, which therefore, by every stroke, _lets down_ the ball _B_,
and thus _raises_ the upper mill-stone. A _proper_ position of the
latter depends on the similarity of the motion of the power-axis _A_,
which winds up the ball _B_, and that of the axis _C_, which _lets it
down_. While these are equal, the weight _B_ remains stationary, and the
work goes on well. But if a gust of wind increases the speed of the
mover _A_, (the pendulum _F G_ confining the axis _C_ to it’s usual
speed) the ball _B_ is immediately raised and the stones brought
closer--which is what the grinding process requires: And should that
gust increase in violence and become a hurricane, the intermediate
cylinder _M_, while producing _that_ effect, carries also with it the
cord _H I_, and thereby raises the bob _G_ of the pendulum, and thus
fits this movement to the increased speed of the mill: raising,
sometimes, the bob to the very centre _F_ of it’s vibration, where it’s
oscillations become rapid enough to _unwind_ all the excess of motion
which the hurricane had occasioned; until, the wind subsiding, the
pendulum acquires a medium length, and things go on moderately as
before.
It may be observed, that the _present_ form of this Machine is not quite
so simple as it might have been made; nor is it so simple as it first
was. The required motions being much shorter than those of a
Dynamometer, the cylinder _M_, among other things, might be dispensed
with; and one of the intermediate wheels be likewise suppressed. And if
we advert to the retarding principle which resides in the pendulum, the
well known conical pendulum might be substituted for the present one;
since from it would arise a regular or equable resistance, opposed to an
equable effort. Some however, might _then_ consider the conical pendulum
as an ordinary centrifugal governor; and, as a mere retarding principle,
it may be thought too complex for the occasion: but I think on the
contrary, that it’s use in this connection, would make this Machine one
of the best of regulators, as well for steam engines as for water and
wind-mills of every description: especially if fitted up with my Patent
Geering.
OF
A MACHINE
_For Forging Nails_.
There is a strong analogy between this Instrument for forging Nails, and
the Machine heretofore given for forging Bar Iron, Steel, &c. The
process of _kneading_ the softened metal, by means of a pair of
alternating cranks, is the very same: but the acting bars or stampers
_A_, _B_, are an addition to the former method. Plate 27, at figs. 2 and
3, gives a representation of the present Machine; which forms the nail
almost instantaneously, by _many_ contacts of the stampers _a b_, (fig.
3) on one of which the figure of the nail is engraven--or rather _filed_
across that stamper, for no _hollow_ figure is required by this System.
The second stamper _c d_ fig. 3, whose place is at _A_ fig. 2, is quite
plain on it’s face; being destined merely to keep the metal to it’s
thickness--as the particular nail here intended, is a floor nail,
requiring a head on two sides only. As to the figured stamper _b a_,
fig. 3, it meets a similar form in the anvil, as at _e_: and it is by
the pressure of these _half matrices_, that the head is formed and the
bar separated from the nail. It may be noticed that the stampers _a b_,
_c d_, are shewn in the figures, as perfectly straight on the face: but
the kind of motion resulting from that of the cranks, would require a
gentle curve here, which a _first_ experiment will sufficiently
indicate.
Some skill would doubtless be necessary in presenting the nail bar to
this Machine; but to make this operation the easier, there should be a
guage, moving toward the working point _e_, by a given quantity for each
nail: say that this guage comes forward at each time a distance equal to
half the length of a nail; and that the thickness of the nail bar is so
proportioned as to contain in that length, enough of metal for the nail
when finished.
It remains to be observed, that the stampers or bars _A_, _B_, fig. 2,
are contained, in the direction of their width; by two plates like _f_,
connected with the anvil _e_, and leaving near _e_, an opening large
enough for the nail-bar to pass easily.
OF
A MECHANICAL ASSISTANT
_For the Tea Table_.
I shall, perhaps, be laughed at by some unfeeling censor, for including
the tea table in the field of my mechanical speculations. But, in so
doing, I seriously mean to be not only attentive, but useful to the
ladies--who, I am _old_ enough to believe, deserve this service at my
hands. My object is to obviate for them the necessity of tediously
wielding a ponderous tea-pot, until real and painful fatigue ensues:
thus emphatically making a _toil_ of that pleasure they had hoped for in
administering comfort to others.
This new method of tea-making admits the use of the common tea
urn--which is placed on the table near the left hand of the fair
distributor. This arrangement is given at figs. 4 and 5 of Plate 27.
There, _A_ is the Urn; and _B_ any common tea-pot, for whose spout, the
cock _a_, has been substituted; and the handle of which has been
slightly modified, so as to make it a proper centre of rotation. This
tea-pot is, of course, _opened_ before it is brought into the position
shewn in the figures. At _C b c_, is placed, first of all, on the table,
_a stand_ of metal, terminated upward by the stem _C D_ which forms a
vertical centre to the whole apparatus: and which is sufficiently fixed
to the table by standing on _three_ feet, _b c_, &c.; under which are
stretched small pieces of Caoutchouc (or India rubber), which, by their
adherence to the table, make the whole steady. By these means, the
tea-pot can be turned round, by a gentle effort, till it comes under the
cock of the urn, from which it receives the boiling water. And, finally,
the tea-board, which is itself circular, revolves on the same axle _C
D_, supported by the casters or rollers _e f_, and bringing successively
_all_ the tea-cups _m_, _n_, _o_, &c., to the spout of the tea-pot,
where they are filled without the smallest difficulty, as will appear by
a further inspection of the figures, and especially by an appeal to
experience.
The above, I should presume, is all that need be _said_ upon the
subject. It remains for some rationally zealous friend of this social
repast, to put these (or other analogous) ideas in practice: in which
enterprize, should he succeed in pleasing the _ladies_, he may depend on
the approbation of every _lord_ who deserves the name.
OF
A COPPER-PLATE PRESS,
_With curious and useful Properties_.
This Machine, as intimated in the Synopsis, was invented expressly for
the use of the lithographic art, as an improvement on the _roller press_
used in Paris when that process was first introduced there. I have,
however, seen in England the description of a Machine which takes the
desired impression _without_ any rolling motion. This Machine, in that
description, carries a kind of scraper, or, as the calico printers would
say, a Doctor, which, pressing on a line only (while drawn over the
paper, or the paper under it), acts successively on every part of the
sheet, and, no doubt, gives a good impression. Of the relative
perfection of these methods, I do not presume to judge, as it is a
technical question; and _both_ Systems are, or have been, used. But,
when intense pressure, joined to much precision, and great economy of
power, are desirable, _this_ Invention appears to me superior to any
thing I have seen used for these purposes.
In fig. 1 and 2, (see Plate 28), _A B_ are two horizontal planes of hard
wood or metal, connected, at a proper distance, by the pillars _C D_,
shewn in fig. 1 _only_. _E F_ are two _Sectors_ of a large cylinder,
united at the point _a_, either by a _good_ hinge or by a joint
composed of a _hollow_ prism fixed to the upper sector _E_, and of a
_solid_ one, more acute, fixed to the lower sector _F_; so that, in the
latter case, this joint works with an insensible degree of friction, and
thus occasions a great saving of power.
In the working of this Press, the joint just mentioned, however made,
describes a straight line, parallel both to the floor _B G_ and the
ceiling _H A_, which have been already shewn to be parallel to each
other: and thus are the joint _a_ and the sectors _E F_ suspended to the
cap or ceiling _A H_ by a pair of triangular braces _I a K_, which slide
smoothly in two dove-tailed grooves _A m_. Moreover, to the lower sector
_F_ are fixed two working arcs _b c_, one on each side of the Press, and
whose radii are exactly equal to that of the upper sector _E_ (whose
circumference, therefore, is invisible in fig. 1.) Further, just above
these arcs, and in the middle of the slide _I K_, are placed, on proper
centres, a pair of grooved pulleys _P_, destined to _work_ the under
sector, without disturbing the motion of the upper one, which latter is
a rolling motion under the aforesaid ceiling _A H_. For the said
purpose, a metallic cord or chain is fixed at _m_ (fig. 1), which,
passing round _one_ of the pulleys _P_, is led to the end _n_ of the arc
_b c_, _n o_; and near _A_ is fixed a similar cord, which, carried round
the other pulley at _P_, is led to the angle _o_ of the same arc _b c_,
_n o_. By these means, the sector _F_ is fixed both in place and
position, as long as the slide _I K_ retains it’s present position and
state. But, again, a system of similar cords, placed _under_ the
ceiling _A H_, near the edges of the upper sector _E_, determines the
place of that sector, in every case, _except_ a change of _position_;
for a _rolling_ motion can still have place, without occasioning any
other change.
When, therefore, a pulling bar, a crank and fly, or any other prime
mover, applied at the joint _a_, carries that joint (say) toward the
pillar _D_, that motion takes place without any _rubbing_ of surface
either above or below; for, when the upper section has rolled under the
ceiling _A H_, into the position _n p q_, the lower section has rolled
upon the plate _s t_, into the position _q r s_: in such sort that the
analogous angles _o t_, _p r_ of both sectors are always found in the
same perpendicular line--or plane--_o t_, _p r_; the cause of which I
shall now endeavour to unfold.
When a wheel, in general, _rolls_ on or against any fixed plane (and the
cords _m P_, _A P_, now act the part of a fixed plane), the point of
it’s circumference the most distant from that plane, moves, in a
direction parallel to it, just _twice_ as fast as the centre of such
wheel, because it is twice as far from that plane, the virtual centre of
its motion: (an example of which is found in the wheel of a carriage,
whose top moves forward just twice as fast as it’s axle-tree.)
Supposing, then, in the present case, the frame _I a K_, with the
pulleys _P_ to glide toward the right hand, the cord _A o_ fixed near
_A_, will turn the arc _b c_ to the right, twice as fast as the centre
of the pulley _P_ moves in that direction: and if this impulse had
acted on the joint _a_, _while fixed_ in position, the arc _b c_ would
have turned _too much by half_. But it so happens (if this expression
may be used), that the joint _a_ itself moves in that direction _once_
as fast as the pulley-pin; so, that the motion remaining to the sector
_F_ is a _single_ motion, merely sufficient to keep the two sectors _E_
and _F_ directly under each other, or within the same perpendicular
lines _p r_, _n q s_, &c.
Thus, it appears, that the turning motion of the two sectors is the
same; and that a given point of the lower one will always _visit_ the
same point of the corresponding plane _s t_, independently of contact
with any substance lying on it; and that, therefore, the pressure,
though successive, is perpendicular, having _no_ tendency to displace or
_pucker_ the paper laid on it; besides which, it may be observed, that
the _power_ of this Press is immense, from the length of the radii of
the sectors _E F_, and the absence of any _rubbing_ motion.
I observe, further, that _racks_, made with teeth on my principle,
either singly inclined with cheeks, as in Plate 14, or with teeth in the
V form, will produce a more certain effect than the cords and pulleys
above described, provided the arcs _b c_, and the upper sector _E_, be
prepared and toothed accordingly.
OF
A REFLECTOR
_For Lighthouses, &c._
The object of this Invention is to join economy of light with splendour
of effect. The means are the following:--
From the nature of reflecting curves, it follows that the smaller a
luminous point is, the more perfectly will its emanations be reflected;
for a _focus_ is a point of the smallest magnitude, if, indeed, it has
any dimensions. My idea, then, is to make a focus of a _line of light_
very minute in it’s _section_, but as large, in it’s contents, as may be
desired: thus securing a considerable _fasces_ of luminous particles
while using them in an economical manner. To this end (see Plate 28,
figs. 3 and 4), I form my reflecting surface of two distinct parts,
having a section common to both, viz.--1st. a concave-parabolic-spindle,
represented at _A B C_, as cut by a vertical plane passing through it’s
centre; and 2ndly, a parabolical bason _E D F G_ (represented in the
same manner) surrounding the former, and so placed as that these
surfaces have a common focus--namely, the _circular line_ of which _a b_
is the section; the line itself being shewn by an elevation passing
behind the aforesaid _spindle_ _A B C_. This _linear_ focus, therefore,
may be two or three feet in diameter; thus imitating the tenuity of a
_punctual_ focus, while emitting a large quantity of rays.
This LAMP, then, consists of an oil vessel, which is formed by the
outside of the parabolical bowl before-mentioned, surrounded, in it’s
turn, by the cylindrical surface _P H_, _I Q_, this vessel communicating
with the wick-ring _a N_, _b O_, by a passage, _H I_, made as thin as
possible, in order to leave the light at greater liberty to pass
downward after reflection. (Where it is proper to add that the
_wick-ring_ is drawn too thick in the figure.) Now, it is well known
that all rays of light issuing from a point, and falling on the concave
surface of paraboloid belonging to that point as a focus, are reflected
from it in lines parallel to each other; and, therefore, a great part of
the particles emanating from the linear (or circular) focus _a b_, and
impinging on the surfaces _F G A B_, and _B C D E_, will be reflected
perpendicularly downward, as at _a_, 1 3; _b_, 2 4, &c. and this being
the case all round the common centre _B_, there will be formed a
cylinder of light of the diameter _H I_, diminished only by the shadows
of the wick-ring, the passage _H N O I_, and the pillar _B L_, when
_that_ is used, which is not indispensable.
If this cylinder of light strikes on the plane mirror _K H_, placed at
an angle of 45° from their direction, these rays will be reflected
horizontally, and, preserving their cylindrical form, may serve as a
powerful _beacon_ to the benighted mariner; the more useful, because
susceptible of those temporary variations of direction and aspect, long
since employed to distinguish one station from another.
But, if it were desired to illuminate a large space at sea, or
elsewhere, the aforesaid cylinder of rays would be received on a conical
surface _K L M_, which would give it the form of an immense sheet of
light, of a thickness (allowing for aberration) equal to the height of
_P L M_, of the same conical surface.
I shall add only one idea--namely, that to light any round space,
building, theatre, &c., this system might be made very efficient by
throwing the sheet of light _M P_ higher or lower on the walls, &c.; or
(altering the angle of the cone _K L M_) by bringing it down to any
position in or below the horizon, as circumstances may direct.
It would be superfluous to say that this Lamp might be furnished with
_all_ the advantages of the argand principle; or, the whole
_wick-apparatus_ might be superseded by a circle of _minute_, and very
numerous gas lights, forming, sensibly, the same linear focus; or a thin
circular _slit_ might produce a real ring of light, strengthened by all
the resources of this new and splendid discovery.
OF
A LONG PARALLEL MOTION,
_For Mangles, and other Reciprocating Machines_.
In the year 1793 or 4, I received _a written problem_, desiring me to
give a plan of a _long_ Reciprocating Motion, that should be driven by
the pit-wheel of a common water-wheel, of given dimensions, and placed
in a given position. In a few days, I produced the drawing now
represented in Plate 29. Its object, as required, was to move the
cylinders _L M_, figs. 1, 2, 3, backwards and forwards, in the _long_
grooves or gutters _N O_, for the purpose of crushing or bruising their
contents: but what those contents were I never knew. I, however,
produced this Machine, considering it as a general thing, and of a
nature to perform most operations of a similar kind. The Machine
consists--first, of a long rack _I K_, much like a narrow ladder placed
on it’s edge, and in the teeth of which work those of a pinion _p_,
whose axis _q_ is connected with the wheel _r_, which receives it’s
motion from the vertical wheel _s t_, which is the _pit-wheel_ in
question. This communication takes place by means of an universal joint
_x_, being a mean of permitting the pinion _p_ to vibrate from side to
side of the rack _I K_, when arrived at either end of it. For example,
the pinion _p_ now turns from left to right, and, being on the other
side of the rack, and _held_ by the chain _v_, it drives the slide _P Q_
in the same right-handed direction, and, with the slide, the two heavy
cylinders _L M_ before-mentioned;--for, the said slide _P Q_ carries
across it’s middle the axle-tree _S T_, which is the centre of both
these cylinders, and connects their motion with that of the slide now in
question. Further, there are rollers placed between the cheeks _V V_,
_on_ which the slide moves horizontally, as guided by other rollers,
placed at the points 1, 2, 3, 4, &c. Again, the ends of the axle-tree _S
T_ are furnished with two bow-like bridles, which, connected with the
pulling bars _Y_, are again fastened to the slide _P Q_, at the two ends
of the present figure.
When, now, the pinion _p_ turns (see fig. 1 and 3), the rack, slide, and
cylinders roll in the grooves, till the end of the rack comes to that
pinion; which, finding no more teeth, swings round the _last_, and
taking a new position, reverts the motion, till the other end of the
rack comes to it, and occasions another return: _ad inf._ This will be
better seen at the third figure, which is an end elevation of a part of
the Machine.--There, _P_ shews the slide and _one_ of the teeth of the
rack (which teeth are longer than the rest, as seen near _L M_, in fig.
1.) In this figure, we see at _A_, a mass of brick-work, covered by the
_sleepers_ 5, 6, 7, &c., on which the long cheeks _V V_ repose. There,
also, the chains _v z_ are seen, connected with ring-bolts, which go
_through_ the bars _a b_, and are _nutted_ on the other side of the
spring-beams _c d_, in order to avoid the commotion which would
otherwise attend every change of motion in the slide and cylinders. For
this purpose, also, and especially to prevent any waste of power at
these moments, there are _mixti-linear_ wedges laid in the gutters, such
as are shewn at 6, which are formed so as to absorb the momentum of the
cylinders, in exact conformity to the time employed by the pinion _p_,
in swinging round the end tooth of the rack; and thus to save all the
power and time possible.
OF
A MECHANICAL SYPHON:
_Which expels Part of it’s Water at the upper Level_.
An ordinary Syphon acts by the pressure of the air on the _upper_ water,
which drives it into the ascending pipe, _because_ there is a (partial)
vacuum made there by the weight of the falling water in the descending
pipe; this being always longer than the first. Thus, in Plate 29, fig.
5, _A B_ shews the rising pipe of a Syphon, and _C D_ the falling pipe,
which is longer, and sinks to a lower level _D_, than that _A_ of the
water, which feeds the machine. _E_, in this figure, represents the
vessel containing the mechanism on which the new effect depends: and
which I shall now describe.