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him on the supposed principle of my PLATING BY ELECTRIC PRECIPITATION, furnace-"I have long paid great atten Sir, I see in No. 956 of your Magation to the operation of smoke burning zine a letter from Mr. Walker, claiming furnaces generally, and more particularly certain improvements in the electrotype, to those constructed on the principle so

for which patents have been taken out imperfectly attempted by Mr. Williams."

by others; but in my opinion, neither (And again, still having never seen a

Mr. Walker, nor any other person has a single furnace of my construction.) “This right to take out a patent for either elecconviction has been forced upon me by a

tro-plating or gilding, as the matter was careful and unprejudiced examination, made public by Mr. Sturgeon in his (careful and unprejudiced !) of a great Annals of Electricity, very soon after the many steam engine furnaces, erected both

original discovery of the electrotype by by myself and others, including several

Mr. Spencer, in a letter to that gentle constructed by Mr. Williams himself.”

man inserted in the work above mentioned. What, Sir, will honest, well meaning men Mr. Sturgeon says in the letter referred to, say of such “careful and unprejudiced “ You will remember the idea occurred cxamination,” seeing that when called

to me of giving medallions, coins, &e., on he was unable to point to a single one

taken by the process of voltaism, silver, which could justify the slightest ground

or golden surfaces, by a similar voltaic for the word “examination,” and for the

process, employing a solution of either plainest of all reasons, namely, that none

of those metals with the prepared matrix such were in existence at the time this instead of a solution of copper. (wisely undated) report was written.

From your obedient servant, For the sake of truth, however, and to

A COUNTRY SUBSCRIBER. do justice to Mr. Armstrong, I must state that he subsequently consented to a letter of recantation, and wrote to my agent, stating, among other things, as follows: “I find that the opinions expressed in

FENN'S REVOLVING OIL STONE. my report before named, were formed on (Registered pursuant to Act of Parliament.) erroneous data, and therefore calculated It frequently happens, that nearly as to mislead. I therefore consider it due to much skill is required in preparing and the public and the inventor, and not less sharpening tools as in the subsequent use to yourselves, to make this explanatory of them; and in the case of engravers in statement, as I find my report has been particular, success depends greatly upon misconstrued and circulated to your in the care bestowed upon the sharpening of jury, and as you have expressed your their gravers. It is in many cases of the satisfaction with this explanation, and highest importance, that a precise angle agreed, at my request, to waive any legal should be maintained between the face proceedings in respect to such injury." and the belly of the tool, and the attain

This paper, my solicitor states, Mr. A. ment of this desideratum by a backward consented to sign, on three conditions, and forward motion upon a stone lying in (dictated by himself,) one of which was, a horizontal plane, is a work requiring is that it is not to be published or circu. more than an ordinary degree of skill for lated, but only referred to at the office its successful execution ; a skill, in which of the solicitor.” Having subsequently those who possess it, justly pride themevaded the actual putting of his name to selves. the paper, (as if that were of any import In order to obviate the greater portion ance, after having admitted its necessity of the difficulty which presents itself in and correctness,) I feel absolved from the the attainment of this object, Mr. Fenn, restriction as to publication. The verbal the well known tool-maker, of Newgateadmission of his error (and consent to street, has registered an ingenious little sign,) was in fact as satisfactory as a writ contrivance which is shown in the annex. ten one.

ed engraving, by means of which any I am, Sir, yours, &c.

artist, or amateur, may readily ensure a C. W. WILLIAMS. fine edge of the required form for his Liverpool, Jan. 17, 1842.

gravers. It consists of a small disc of turkey stone a, mounted upon a suitable holder and axle, which has a small pinion

THE SUPPOSED PERCUSSIVE ACTION OF STEAM.

89 on its outer end on the opposite side of on the surface of the revolving hone with the supporting side frame or bracket; a a piece of woollen cloth, the tool is held multiplying wheel b, furnished with a against it at the required angle, and the handle, takes into and drives the pinion. stone made to revolve by turning the A small quantity of oil being spread wheel b.

[graphic][subsumed]

The advantages of this contrivance, the very best quality only, and superconsist in producing with little care, and sedes the use of any containing flaws or with great facility, any desired angle on imperfections, which it is difficult to the edge of every description of tools ; the avoid when long slabs of stone are rewood stand forming a rest for the right quired as in the ordinary modes of hand which holds the tool, while the left sharpening edged tools. The continuity gives the necessary motion to the hone. and rapidity of the motion thus proThe vertical position of the hone, also duced, soon effect the desired sharpenenables the operator to see from time to ing. We have no doubt that the adtime, the angle which is being formed on vantages of this contrivance will soon the tool, while the smallness of the stone cause its very extensive, if not universal facilitates the employment of those of employment among artists.

THE SUPPOSED PERCUSSIVE ACTION OF STEAM. Sir,-Mr. Parkes appears to me to

search of a cause : this cause he styles have fallen into an error which many the “percussive action." other philosophers have done before him, The first idea which the word “

perviz., that of inquiring more into causes cussive" gives rise to is, that of the than effects. He imagines that, accord. steam travelling through a partially vaing to the recognised laws of expansion, cuous space before it comes in contact a greater portion of work is performed with the piston, and acquiring through by the Cornish pumping engines than that motion a force similar to that acthe steam used would warrant us to ex quired by any body in falling; or movpect; and without taking into considera ing in any direction with a continuous tion the possibility that his calculation of propelling power applied to it. Such, the effect produced may be erroneous, however, cannot be the view taken of the he sets off into the regions of fancy in subject by Mr. P., or he must obviously

be in error, as decidedly the reverse of above the slide, and marked a pressure percussive action is produced by so ad of 40 lbs., the mere abstraction of the mitting the steam ; for however rapidly slide would cause the quiescent mercury a body of steam may flow into a partial to rise suddenly, and mark a pressure of vacuum, it must expand far more rapidly; 60 lbs.; and yet, all that we have done and the outward portion, or that which to the steam has been to substitute one falls on the piston first, will necessarily base for another. If such an effect were be attenuated in a great degree, and im- possible, we may draw from it the most part a force thereto little exceeding that extravagant conclusions; for if a number of the partial vacuum which previously of these cylinders, pistons, and slides existed.

were fixed directly to a boiler, the simple If, then, the travelling-if I may so abstraction of one slide would suddenly speak—of the steam gives diametrically raise the force in the boiler from 40 the reverse of “percussive action," we to 60; and if, at the precise moment shall gain a maximum of this imagined when the steam was exerting this 60 lbs. force when the vacuous space through force, another slide were suddenly withwhich the steam has to travel, between drawn, the pressure would be raised to the induction valve and the piston, is 90 lbs.; and if another were then withthe smallest that can be obtained. This drawn, it would be raised to 135 lbs.; is so palpably plain, as to admit of no and so on ad infinitum. Your readers dispute on the subject; and yet, if Mr. will, I doubt not, smile at the absurdity P. admits it to be the case, his theory at of such a calculation, but those who are once falls to the ground. Let us ima inclined to weigh the matter, will find gine, for instance, a cylinder having a that the idea is arrived at by strictly inpiston fired in any part of it. Above ductive reasoning; and, absurd as it is, this piston let us imagine a slide of in it must hold good, as long as this "per. appreciable thickness, yet strong enough cussive theory” does. to bear the whole pressure of the steam, Such, or nearly such, were the ideas and placed so as not to touch the piston, which occurred to me when this theory yet at an inappreciable distance from it, first came under my notice; but as I and let the induction port be double or imagined Mr. Parkes advanced it merely treble the usual size. Now, suppose the as an opinion, I took no further notice of steam to be full on, and pressing on the the subject. I find, however, from a slide with a force equal to 1,000 lbs., can subsequent paper of Mr. P.'s, that he we, without risking a charge of absurdity, still upholds his theory, and brings forimagine it possible that, by suddenly ward what he seems to consider indiswithdrawing the slide, the steam may be putable arguments in its support. made to exert a force on the piston, ex I have not the abstract of his last paper ceeding that which it had previously ex by me at present, but, if I recollect right, erted on the slide ? If it would exert he states that if a mercurial gauge be atthis extra force, whence comes it? The tached to the cylinder, the sudden impact body of steam has not moved an appre

of the steam will cause the mercury to ciable distance, and consequently cannot rise high enough to denote a pressure of have acquired an appreciable momentum; 60 lbs. per inch, when the pressure of and I have just shown that, if it had the boiler is only 40 lbs.; and that when moved, the reverse of percussive action the steam is admitted gradually, no such must have resulted. This is so obvious, effect is produced. I believe 40 to 60 that I may be charged with prolixity in are the proportions ; but at all events we giving further illustration ; nevertheless, will assume it to be so, for the sake of I will say a word or two more.

round numbers. Mr. P. also states, that If, by suddenly withdrawing the slide, in the larger engines the cylinder covers the steam is made to exert a force of are deflected, or bulged outwards, when 1,500 lbs. on the piston, instead of the steam is admitted suddenly; but when 1,000 lbs., (the pressure it previously slowly, no such effect is produced. exerted on the slide,) the same, or nearly Now, to a merely casual observer, the same, effects must be produced on these two arguments seem to tell strongly the parts of the cylinder submitted to the in favour of the “ percussive theory; action of the steam; and, consequently, but when examined into, we find them if a mercurial gauge were fixed a little to result from causes entirely independent

THE SUPPOSED PERCUSSIVE ACTION OF STEAM,

91 of an additional, or "percussive force.” bulge or force the cylinder cover outWith regard to the first argument, I wards. As soon as the piston begins to would ask, how can Mr. P., or any one move, the pressure gradually decreases else, imagine it possible that a stream of from 100 to about 75, and the cylinder mercury driven 100 inches, with the cover assumes its proper form. I need great velocity it must acquire from hay not enter into any elaborate argument to ing so great an unbalanced pressure on show why the cylinder cover is not deone side, would suddenly stop and re flected when the valve is opened slowly, main quiescent, when it had risen a suf as every one, who knows any thing of the ficient height to balance the pressure of steam-engine, knows there is a great loss the steam? The momentum acquired of power occasioned by so admitting the by such a velocity would be sufficient to steam-not owing to the loss of “percarry the column considerably higher cussive force," but owing to the wireeven though the whole pressure of the drawing and undue expansion, which is steam were instantaneously removed the natural result of admitting the steam when the gauge marked its proper level. too slowly. What, then, ought to be the effect when If I am rightly informed, Mr. P. in this momentum is aided by the continued his calculation of the effect produced pressure of the steam? Theoretically, by the Cornish engines, takes the maxa body of mercury under such circum imum pressure of the steam in the cylinstances should rise to double the height der at 27 lbs. ; which 27 lbs. is continued warranted by the pressure of the steam; during one-sixth of the stroke, the steam provided means were adopted to prevent being expanded during the remaining the column acquiring additional length five-sixths. If this be his mode of proor weight after it had reached the 100. ceeding, he is not likely to arrive at a

Practically, of course, such an effect just conclusion, as to the relative quancannot be obtained. The deflection of tities of steam consumed and work done ; the cylinder cover is, apparently, a more as it is obvious that the steam is exerting weighty argument; but if analysed, is a pressure nearly equal to that of the found to result from an entirely different boiler at the commencement, when the cause to that assigned by Mr. P. Be piston is moving very slowly; which fore, however, we investigate this point, pressure decreases as the velocity of the I must request your readers to bear in piston increases, and consequently exmind, that in the engines Mr. P. ex pansion is going on during the whole of perimented on, although the pressure of the stroke, instead of only during fivethe boiler was about 100 inches of mer sixths. cury, that of the steam in the cylinder Not being thoroughly conversant with was only about 75, with the steam full the action of Cornish engines, I should on; owing, of course, to the velocity of incur a risk of error in speaking thereon; the piston being too great, or the induc therefore, I wish it to be borne in mind, tion too small to admit of the steam flow. that the following remarks on the crank ing in with sufficient rapidity.

are not made in reference to them. Now, let us imagine an engine to be reason for speaking on this subject is in working under such circumstances, the reply to an assertion of Mr. Parkes, that piston at the top of the cylinder, and the a crank engine cannot possibly realize steam admitted suddenly. The space the advantages gained by a non-rotative; between the cylinder cover and piston and I see by a reference to the patent being small, in comparison to the size of list, that a patent has lately been taken the induction port, is almost instantly for machinery to be used as a substitute charged with steam of nearly equal pres- for the crank, probably with a view to sure with that of the boiler; before this obviate the supposed disadvantages asspace can be enlarged, the vis inertia of signed to it by Mr. P. Now, as far as I the immense mass of matter, comprising can perceive, a pumping engine, reguthe piston, beam, pump-rods, &c., and lated by a crank and fly-wheel, would materials to be lifted, has to be over realize more advantage than a non-rotacome; and sufficient time will be required tive, especially while the latter labours to do this, to adınit of the pressure above under such a palpable disadvantage as the piston becoming equal to that of the the one Mr. Parkes experimented on, boiler. This pressure is sufficient to viz. not admitting the steam with suffi

My

cient rapidity to keep up a due pressure the other, is laid down again, and the car in the cylinder when the steam is full on. riage thereby propelled along. In a crank engine, the extreme slowness The second part of the invention consists of the piston during the first part of the in the application of similar machinery on stroke, allows sufficient time for nearly

board a vessel, for propelling it. the full pressure of the steam to be

The claim is, 1. To a mode of propelling maintained in the cylinder; and conse

carriages by means of wheels or endless

chains, worked by suitable gearing, and actquently, much more may be admitted during one-eighth of the stroke, than

ing with a ground-chain ; 2. To a mode of Mr. P. obtained in one-sixth. I should

warping vessels by means of wheels or end

less chains, worked by suitable gearing, and imagine there would be considerable dif

acting with a chain of single links, whereby ficulty in arranging a merely reciprocat

one chain is rendered sufficient for the pasing engine, in such a manner as to keep

sage of vessels in opposite directions at the up a full pressure while the steam is on;

same time. as such a pressure cannot be maintained James HENRY SHAW, OF CHARLOTTEunless the piston is loaded so as to offer STREET, BLACKFRIARS-ROAD, JEWELLER, a certain modicum of resistance; and if for improvements in setting wheat and other the load be thus increased, the weak ex seeds. Enrolment Office, December 18, panded steam at the end of the stroke 1841. will not be sufficient to keep the load in These improvements consist in furnishing motion. With a crank and fly-wheel, means by which given quantities of wheat or both these disadvantages may be obviated:

other seeds may be set at regular intervals the slow motion of the piston at the com

apart. A frame is mounted on two running mencement of the stroke, allowing the

wheels; two smaller wheels are also applied to admission of nearly full pressure steam;

side frames in front of the machine, which ad. and the momentum of the fly-wheel,

mit of adjustment, so as to regulate the depth

of furrow produced by the ploughs, which acting, as it does, with a gradually in

are fixed in the front rail of the framing by creasing leverage from the middle of the

wedges. On the nave of one of the running stroke, admitting of the steam being ex

wheels a cog-wheel is fixed, which, by means panded to any degree of rarity above

of a clutch-box, can be thrown into or out that required to overcome the friction, &c.

of gear, with a corresponding cog-wheel on Yours, respectfully,

the axis of a seed cylinder. This cylinder is J. BRITTEN. divided into a number of compartments,

corresponding to the rows of seeds to be deposited. Around each compartment there is an apparatus for regulating the quantity

of seed, and depositing it at the prescribed ABSTRACTS OF SPECIFICATIONS OF ENGLISH

distances apart. PATENTS RECENTLY ENROLLED.

The seed passes down rectangular tubes, SIR SAMUEL BROWN, KNIGHT OF THE the lower ends of which are kept closed by Royal HANOVERIAN GUELPHIC ORDER, spring valves, which are opened at proper COMMANDER IN HER MAJESTY's Navy, intervals, and to a proper distance, by a OF NETHERBYERS-HOUSE, Ayton, BER series of curved bars affixed to the machine. WICKSHIRE, for improvements in the means The claim is to combining mechanical apof drawing or moving carriages and other paratus into a machine, by applying depositmachinery along inclined planes, railways, ing apparatus, and suitable parts connected 8c., and for drawing or propelling vessels therewith, to a revolving cylinder. on canals, rivers, and other navigable waters. WILLIAM CHESTERMAN, OF BURFORD, Enrolment Office, December 18, 1841. OXFORD, GENTLEMAN, for improvements

The first part of this invention relates to in filtering different liquids. Enrolment a mode of propelling carriages by means of Office, December 21, 1841. a ground chain. For this purpose a cranked Under this deceptive title we are presented axis, turning in suitable bearings upon the with another new coffee-pot, which seems to framing of the carriage, and driven by con us to be an inferior modification of the very necting-rods from the steam cylinder, carries excellent contrivance of Mr. Platow. a cog-wheel and a chain-wheel. Two other This coffee-pot is made of tin plate, with axes also carry respectively chain-wheels and a wooden handle attached horizontally to cog-wheels, which are driven by the former. one side of it; a hole is made in the bottom On motion being given to the machinery, a of the vessel, to admit a heater to enter a ground-chain is progressively picked up, and tube which passes up the centre of the pot. passing under the wheel on one axis and over The ground coffee being placed in the vessel,

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