Part 14

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.

_B_ and _C_, fig. 4, are, one the ascending pipe _A B_ of fig. 5, and the other the descending pipe _C D_. They are surmounted by two cylinders, of unequal capacities--this inequality bearing a given proportion to the difference in the heights of the rising and falling branches of the Syphon. In each of the cylinders works a piston _a_, _b_, which, I think, need not be stuffed, but _well_ fitted. The large piston has proper valves in it, to let the water pass upwards, at all times; and the small piston has a valve _i_, opening upwards, by means of the mechanism we are now describing; and closing itself merely by the arrival of the piston into it’s present position; for the screw _c_ prevents the valve from rising higher: _e_, _f_, are two arcs belonging to the lever _E_, and being circles round it’s centre of motion. They are cut into teeth, on my Patent principle, and work in the racks similarly _toothed_, which give motion to the pistons _a b_, or receive it from them. Further, behind the stand _F_, common to both levers, vibrates, on a pin, another lever _g h_, the use of which is to _work_ the aforesaid valve _i_ in the small piston; and this it does, by means of the weight _h_, in the following manner:--The machine being supposed in the present state, the Syphon will act, as usual, through the valves of the large piston; and the water pressing on the small one, with a power proportionate to the excess of it’s column over that of the other piston (_a_), will raise the latter as fast as the piston _b_ descends; but the area of the piston _a_ being _larger_ than that of the piston _b_, there will be a pressure within the vessel _b c d a_, that _must_ expel (through any prepared aperture at the top) a quantity of water equal to the difference of area between the two pistons, multiplied by the stroke of both: the real quantity of which will ultimately depend on the difference of level between the higher and lower water; or between the lengths of the rising and falling branches of the Syphon, _B_ and _C_. When, therefore, this stroke is made, the end _h_ of the lever _g h_, which carries the ball, will touch the screw _d_, and stop the descent of the valve _i_, which will thus be opened; when the water will have free egress through the descending pipe _C_, and the piston _b_ will then rise through that water by the weight of the piston _a_, the valve _i_ being _kept open_ by the action of the weight _h_, until the piston _b_ has risen to it’s present position, when a new stroke is prepared, for the same reason as before: and thus may water be carried over a hill of (about) 30 feet above the level of any stream or pond, and dropped into a _lower_ canal on the other side, with the condition of leaving a part of that water upon the hill, proportionate to the difference between the level from which the water is brought, and _that_ to which it is carried.

OF A FORCING MACHINE, _For taking on and off the Cylinders of Calico Printers_.

The two figures, 1 and 2, of Plate 30, are intended to make this Machine known, assisted by the following description:--The first is a front view of it, and the other a partial view from above. In the former, _A B_ is the frame formed of, and firmly connected with the two columns _C D_, which are fixed strongly to the ground, at such a distance below the ends _C D_, as to place the aforesaid frame at the height of about two feet, or higher, if convenient.

In the two cheeks of the frame _A B_, are cast or bored two round holes for receiving the gudgeons of the _swivel_ _E_, one of which gudgeons is also seen at _E_, in fig. 2. This swivel turns in these holes; and it is itself perforated with a round hole just large enough to receive freely the body of the mandrel _F G_. This mandrel has now on it the cylinder, which is to be taken off. _I K_ are, moreover, two ears or studs cast or welded on to the top and bottom of the said frame _A B_, and at exactly the same distance from the centres of the swivel _E_ before-mentioned. These _ears_ receive the ring-formed ends of the bars _L M_; see also the bar _L_, in fig. 2. To these bars is firmly fixed the cross-bar _N O_, which forms the _nut_ of the screw _P_, by means of which the operation of the machine is duly _prepared_; for, now the cup _Q_ (in the centre of which the screw _P_ revolves against a proper shoulder) receives the end _G_ of the mandrel, which it presses forcibly, while the whole is in the position _E L_, of fig. 2; that is, when the two centres _E_ and _R_ form one right line with the bar _L_, figs. 1 and 2. To complete, then, the process of driving out the mandrel, the bars, mandrel and cylinder are, at once, strongly made to describe the arcs _a M b_, _a c_; the mandrel revolving round the centre _E_, which is that of the swivel and the bars round the stud _R_. But, in thus revolving, a given point of the mandrel describes the _quadrant_ _a M B_, and a contiguous point of the bars _L M_ describes the quadrant _a c_; insomuch, that the mandrel _must_ have been forced out of the cylinder in direction _G F_ by the distance _c b_; where we observe that, at the beginning of this motion, the two curves _a b_ and _a c_ coincide in their movements, and only begin greatly to diverge from each other in the latter parts of these motions (see _M b c_.) The power, then, of this machine, when the cylinder sticks fastest to the mandrel, _is infinite_: and this power becomes weaker, and the velocity greater toward the end of the operation; that is, when the cylinder has slackened on the mandrel, and no longer requires to be driven with the same force as at the beginning. It may finally be observed, that the bars _L M_ are suspended by an oblique bar or chain _S N_ to the ceiling of the room just over the stud _R_ or _I_, which is their real centre of motion, in the above-described process.

OF A SYSTEM OF MACHINERY, _For cutting and trying Tallow by Power_.

The wheel _A B_, Plate 30, fig. 3, _was_ a horse-wheel, but may be a _first motion_ of any given kind. It is placed on the ground-floor; and over it’s centre is another shaft, having on it’s upper end a chopping block _C_, which revolves with the wheel _A B_, as turned from below. In this wheel, _A B_ geers a pinion _D_, driving the lateral shaft _D E_, which has two functions: the first to work the lying shaft _F_, and by means of the cams _G H_, to lift the contiguous stampers; and, by means of the knives _I K_, to cut the tallow on the revolving block before-mentioned. Over this block is fixed an oblique scraper, which takes the tallow as soon as it is cut, and pushes it down an inclined channel, placed at _C x_, into the boiler. The second use of the shaft _E_ is to turn the _mill_ _M_, (better shewn at fig. 4), which is let down into the boiler, in one stage of the process, and drawn out by the tackle _N_, when not wanted. The use of this mill is to tear the fleshy parts of the substance, while in the act of boiling, and thus to disengage the tallow with so much the less heat, in order that it may be so much the less coloured. Besides this machine, there is a grapple _L_ to be first used, which stirs the tallow in the boiler by the rotatory motion of the arm _x_. This position of the grapple would alone indicate what I have yet to observe--namely, that the boiler is a kind of ring, the section of which is the line 1, 2, 3, 4, and it’s depth 1, 2, or 3, 4. To prevent, still further, the fat from being burnt or coloured, the flue for the fire is conducted solely under the bottom of the boiler, as shewn by the dotted lines in fig. 5: the smoke or heated air being forced to make two revolutions under it, as indicated by the arrows in this figure, where we see more particularly the fire-place _F_ in close connection with the rising shaft of the chimney at _G_; and this is so, because, with so great a length of horizontal flue, the fire would not enter the chimney till it had been heated to a first degree. There is, therefore, an opening into the chimney at _a_, and the fire, in lighting, is suffered to escape directly from the fire-place into the chimney; by which means, continued a few minutes, there is draught enough created to make the fire take its useful course through the flue afore-mentioned. I may just observe, reverting to fig. 3, that _O_ shews the fire-place _in elevation_, and _p_ the entrance into the flue, which last is double under the boiler, as shewn in fig. 5. Finally, the 4th fig. shews an end view of the _tearing-mill_, before-mentioned; but here on a larger scale, _A B_ being a part of the side of the boiler.

OF A WASHING MACHINE, FOR HOSPITALS, _Which confines the offensive Matter till cleansed away_.

Doubtless, the salubrity of every place, where _many_ people are collected, would be much increased, if all impure exhalations were expelled as soon as formed; and this is especially true of those awful but sublime receptacles, provided by Philanthropy, for the sick, the wounded, and the dying! To assist in the work of purifying the atmosphere of these doleful abodes, was the object (30 years ago) of the VENTILATOR, presented in page 170 of this work. But, I conceive, that a share of evil, quite as great, resides in the putrescent qualities contained in or connected with the clothes, the bed-linen, the dressings, &c., of the inmates of an hospital; to whose sacred claims on the efforts of every good citizen, the present article is devoted.

This Washing Machine (see Plate 31, figs. 1 and 2) is a triangular (or square) box _A B_, furnished with a lid _a b_, so fitted, as, when screwed down, to be hermetically closed.--And, N. B., to facilitate _this_ operation, I use in it a particular kind of screw (invented for the _hose_ of fire-engines), which I shall now describe. I take a common screw, with it’s nut, and cut away the threads of both, at two opposite _quarters_ of their respective circumferences, so that the screw can _enter the nut to the bottom without turning_; and the stuffing between the shoulders is so well fitted, in thickness, as to secure the penetration of the threads of the nut and screw the moment the latter _begins_ to turn. There is thus a full quarter of a turn, in which the nut and screw will press as strongly as though the threads had not been cut away; and thus are _nine tenths_ of the time required to use a common screw _saved by this simple process_: and thus, then, I close the lid afore-mentioned.

This Machine is further composed of a wheel _C D_, and a pinion _E_, to turn it with, either by hand, or by any proper application of power. The wheel turns the box _A B_, and thus agitates the contents in a way not dissimilar to the operation of the dash-wheels of calico printers. But, again, this wheel and vessel turn upon _two hollow gudgeons_ _c d_; one of which is destined to convey cold water into the wheel from the reservoir _F G_, to regulate which is the use of the cock _f_: the stuffing box _e_ being made as _good_ as possible, in order to prevent all leakage, either of air or water. The second hollow axis _d_ serves two purposes: it gives a passage to the fetid matter of which the expulsion is desired, and conveys it through the cock _g_ to the _sink_ or _sough_ below _h_, _without any communication with the surrounding atmosphere_.

But we said this hollow gudgeon had a second use: it is to bring steam into the revolving vessel _A B_, from any proper boiler beyond _K_, when that part of the process requires it.--There are, moreover, two partitions _C D_, _l m_, made near the ends of the vessel, and pierced with many holes, in order to suffer the cold water to flow in, and the dirty water to escape, without choking up the respective passages: and, finally, at the eduction end of the Machine (see _n_, _o_, _p_, fig. 2), there are placed three pipes, reaching from the angles of the box to the hollow centre, and furnished, at those angles, with valves, opening outwards; which thus form a kind of hydraulic machine to raise this matter from those places to the hollow centre, and thus, after a certain number of revolutions, to expel it entirely.

The process, then, for cleansing the objects contained in the vessel _A B_ (including the condition of cutting off all communication with the ambient space,) is as follows:--