~4 Patent for an Oval Cr~u.barreL

as a magical compound. Our readers will fital:all the essential parts of the materials above mentioned, described in the several patents for preparing iron and steel in our preceding volumes.--[/b.

To Jonr~ BaEVER, of Manchester, in the County of Lancaster, Gen- tleman, for his having hwented an 1reproved Gun Barrel

T n ~ pateateCs invention is the making gun barrels of an ovalor ellip- tical figure in the bore~ instead of cir(ul'ar, as usual~ which he con- siders will discharge shots in a more effective range~ tfian the circular barrels of the ordinary construction.

I t is proposed, to take the ordinary kinds of gun barrels in' their rough stat% after they have been welded into tl~e cylindrical tbrm usually adopted~ and (o heat them red-hot, then !~ass an elliptical rod into the barrel by hammering or otherwise, so as t'o enlarge its diame- ter in one direction, and to compress it in the other; that is~ press the circular tube into an elliptical figure, When the barrel has been thus tbrmed, it may be completed by drawing~in the manner that tubes are cmnmouly drawn, and ther; finished~y the insertion of a breech in the ordinary way; after which the gun is to be fitted to a stock, and the other parts appended as usual.

The manner by which the barrel is formed into the elliptical figure, constitutes no part of the invention: that may be done by any con- venient means, the substantial part of the invention being the em- ployment of elliptically bored gun barrels~ instead of circular bores as usual, and which the patentee considers will' give a more effective range to the charge of shot than the old form.~EnroUed Jtpril, 18~26.

[15.

On the EconoTn!/ q" "usb~g highly Elastic Steam expansively. It!1 J A c o~ Prau:j x s, Esqr.*

[~ ~Fith a Plate.]

'I'~L.', diagram~ figs. I and 2, in the plateiwill show the economy of using steam expansively, and also the metlmd of compensating for the inequality of the pressure on the piston, which, if steam of 40~lbs. to tile square inch is used, and stopped off at tile quarter stroke, will end its stroke at lO0lbs, per inch. ' Ihe diagram will also show that the velocity of the piston is continually varying, while the crank is uniform in its motion:~

From repeated experiments and mucli rettection~ I am led to be- lieve that there is great economy in using very high steam~ and that

4 The above article is subjoined to that on the Explosion of Boilers, in the pampblct received from Mr. Pcrking.~[ Editor.

• J It is ~ot pretended thatthis diagram is mathematieaUy accurate; the object being merely t o cxplalu to the practical mechanic, in a sufficiently clear and con- cise matron:r, the principle of the advantage gained by using steam e~pansively.

Mm P~rtKir,'s on usbzg 5Team e.zTan~qvely. ,$~

expartsivelv; that the higher you can practically use t h e ~ a m the sooner" you may cut it off. The diagram shows the gain i n cuttin~ off the steam at quarter stroke. Let the piston, whiett is represented by the line k. 1 a. descend to i. b., being one quar- ter of the stroke, witht alc°nstantbPressur-e le te st, m ecu oft" ~nd°f 4001bs. per square inch. At this point, t ea t a expand to double its voh.ne; when it arrives at h. c. it will be exerting a pressure of f~001bs, pet" inclb producing a mean of g001bs, per inch, througk the qua"ter stroke. Let the steam agairl expand to double its volume, and the piston will finish its stroke a t f . e. at 1001bs. per inch, giving a mcan of 1501bs. per inch for each quarter, which add to the other two quarters, 400. 300. 150. 150. and the whole sum will be 1000, ~ giving an average pressure of ~50 per square ~nch. It will be seen that, when the stroke is completed, the cylinder will be filled with steam at a pressure of 1001bs. per indh~ which witl be the same in quantity as though the steam had begirt with a pressure of 1001hs. pet' inch, and continued all the strokff at ~hat. pressure.,, . By usino'~ the. same. quantity of steam expansively, bcgmmn~ at 4001bs, there ts a ~am of 150 per cent. If the steam is ~]sed at 6001bs. pet" inel b and ~ t oft'at one-~ighth~of the sta'oke~ ~$5 per cent. will be the gain. To compensate for the unequalpressti~

• . . . . i . . . .

pistons is at its greatest power, the other is acting with a diminished ~tower. • The piston 1, fig. l ?. in de~cending from a to b, moves in the same

~,~m through only halt the space through winch the crank moves, as ,,~ill be seen by its path fl'om 1 to S. A lbrce of 4001bs. is exerted o~ lhe square inch (that being the pressure of the steam,) in the first quarter of the stroke: at t~his point the steam is cut off¢leaving the other three-fourths of the stroke to act expansively. The piston 1,

!i! 2 i~'~!~ ~2tiPsele2qti ~ani~21 fa 'ct; mS t;;°nkeat ~o hn: nn e P:'Ste~noulglfit~r lalb;gr2

It will be seen, that whiie the piston 1, fig. 1, bg.s performed one- lburtl~ of its stroke, that the piston 1, fig. ~, has i~oved from e to 6, performing seven sixteenths of its stroke in the4jame time. The mean in each (luarter~ from c to e, fig. 2, being 150]bS.~ the anaount of pressure to be added to the first quarter of the stroke of the piston, fig. 1, (which was 400lbs.) is'2751bs., producing atl available power of 6751bs. at this part of ti~e stroke. The piston, fig. 2, now moves but two-sixteenths of its stroke fl'om 6 to e. and f to 8~ while the crank moves through two of its divisions, from 6 to 8, which would~ in another part of its path, move (within a fraction) with the sa~t~ velocity as the piston. The piston, fig. 2, in moving from 6 to e, gives a power of ~51bs., being the lastof the ext~ansio~ which er~d~

* If the steam had continued the whole length of the ~troke ~t 4001b~. per ~quare inch, the sura wouM have been 1600lbs. consuming four tiral~ilae steam with the addition of only 60 per cent. to the power.

VOL, I V . - - N o . I . - -JuLY, 1 8 2 7 . ~ 4

~6 Ma. Pm~1Ns on u.~ing S l eam expanalvely.

at 1001bs. l~er inch. T m pMon, rio=. 2, in moving fro:n f r o 8~ being the beginn{ng of the stroke, gives a~power of 1061bs.; thu~ a power" of l~251bs will be aetim~ on the niston 1, {i,~ 1, while moving~from b, to d. gwmg a power of 475tbs. to which add 1~5, will show a power of 6001bs. at this part of the stroke. The piston 1, fig. 1, now de- scends fl'om d to e(being the last quarter of the stroke, giving 1251bs. of power to act with the piston l, fig. 2, while moving from 8 to h, giwng~a T)uwer ot 6001bs., add to this the t~51bs, and it will give a power ol t 7:~51bs. at this part of the stroke. The piston 1, fig. 1, now begins its stroke of 4001bs. per inch at f, and continues to g, with the same power, while piston 1, fig. 2, moves from h to 1~ giving a power of 30()ll)s. to be added to the 400Ibs., obtained at the tlrst quarter of the stroke of the piston 1, fig. 1~ a t f and ,g~ producing at this part ol the strokc~ 7001bs. of power. The piston i~ fig. 1, now moves fi'om ,~' to i, giving a p()wer of 475, while the piston t, tig. ~ moves from 1~ to k and a, to 2, giving a power of 1~5. which add to 475, gives a power of 600 at this part of the stroke. The piston 1, flg..l, now moves fi'om i to I, being the last quarter of the stroke~ giving a pawm- of ly25tbs., while the piston, tl~. ~, moves fl-om ~2 to e, prod{icing a lmwcr ~)f G0(); to which add l~51[)s, will make 7~5[bs. at tMs part of the str,,Le.

By this aI'rarlx(!nlent ~ it wilt be seen, that a com>m~ation is ol)tain- v.(l~ ~iving a more equable power than that which'is produced by the single engin% whether high or low pressure, sincc it is well known~ that at two points of the revolution of the crank, the power c(:ases~ during at learnt one twelfth of the time, which is the reason that so la%e a fly-wheel is necessary. It is particularly applicable to steam-boats~ and may be used to gl'eat advantage in tl~e double pump, as well as the balanec-b )b lifting pump, used'in Cornwall for minino_" ~)urDoses~ by the use (~l pro )er gearing. The present single stroke, expansive engines, used in Cm'n;~vall f0r pumping~ are preferred to all other% on account ~)f their economy, although they are. very limited as to the extent vf the expansive prmclple, tbr want of comi~ensation , as nearly the same power ~s waisted to finish the stroke of the pure D as to be- gin i{.

The variafi,'m of 0ae velocity of the pision~ occasioned by the com- pound motion of the cral~k~ and connecting rod~ is not takm~ into view

this diagram. .,\:~ the connecting rod is intended to be four diame- ters of the path o[" the crank, the variation will make no practical objection, bein;~, at its greatest value, but one-thirty-second part of its range. If (ira engine should be worked bya connecting rod, as is sometimes the case {n steam-boats, say only one diameter of the path of the crank, the variation at each end of the stroke, would amourtt to a practical ,lefect, since the piston would move with nearly three times the velocity at the lowest quarter of the stroke, that it wouhl at the first: quarter. Thus circumstanced, the crank must be above the cy!imter.

As tim law of expansion seems not yet to be settled, an arithmetical expar, sim~ has been used for this diagram, which, from its approxima- tion to the real law, will be quite near enough fin' practical l~urposes.

Mn. 13rowl~E on the Patent Law.

Many who are of the school of Tiltock and Wolf, believe .that; fi~ expahsive power vf steam depends upon heat only; while tla~ ~ ~ experiments are said to prove that elasticity depends simply on ~ sity, without rezarding temperature, viz., that if a cubit foot of stea~' at'atmospheric ~wessure, weighs one ounce, 50 atmospheres of stcaua wouhl wei,qt 50 ounces; but Dalton, who is undoubtedly much near¢l, the true la~', would make 50 atmospheres weigh but about 84 ounceg.

I have no doubt that the nearer the atoms of ~iater are made to approach each other, by compression, thegreater wi I be the repu l s~ action of calorig and that, in a more rapidratio than has hitherto been allowed, especially in highly compressed steam. Its comparative density with the increase of power, diminishes faster than has been supposed evcu by 1)alton.

FOR THE FII.ANKLIN JOURNAl,.

~M EC ]l AN IC AL .JUIIISPRUI)ENCE.--No. W i l l .

BY PETEB. A. BROWNE) ESQ,

On the Law of Patents Jbr New and Useful Inventions.

ON 'FHI . ; 1)EFEN', ;I ,~ W | l i C I { MAY l l E MAI) I , ; .

'l'he diltiwent farts o!" the acts of Col~g, rcss, respcctillg patents, may l)c thus arr;m:.ged. 'i'he 6th sectiol~ of the act of I79S, pro- vid'es, that when auy action is brought for a breach of the patent right,-the (let\:lMant may plead the general is.~ue. As the Sd sec- tion of the act of the 17th of April, 1800, (which was enacted to supply the 5th sec. of the act of 1798) provides, that the action shall

1. That the specification, iiled by ~he plaintiff, does not contain the whole truth relative to his discovery.

~2. That the speciiicatioa contains more than is necessary, to pro- duee the desired eii~et.

.% Tha~ lhe thiua thus secured by patent, was not originally dis- covered by the pate~lte% but had been in use, or had been describe d in some public work, anterior to the supposed discovery of the pw. tentee.

4. That the pateutee had, surreptil:iously, obtained • paten~.fo~ the discovery of auother person. :;,: ..

To the 1st and ~d defences, the act adds, that the eoncea!~6a% or addition, must full)~ apl)ear to have been made tbr the purp6~e of deceiving the public.~ 2h'ul in order that the plaintiff may:~aot be takc~t by surprise, by giving either o[ these defencesia.eVhle~ic~