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Java; Nouronk, Mauritius ; poukpin, Burmah (Bntea /cuidosa).

faameUa »/aire, E.I. Körung oil, India.

Park-U biglanduUuo, E. I.; 18 per cent. Also stsrchyieldiug plant.

Ouraia. opochala (Pentaclethra macrophgUa), Gabon, Fernando Po, Ac., good for culinary use, lubricating machinery, and eoapmaklng. 48 per cent.

Oleo deCamaru, Brazil,Tonquiu DetsuDgpterix odorata), perfumery and medicine.

Ben oil {Moringa ptetygosperma), morunghy yeVinai, I<iTii.Mil; morunga noona, Teloogoo. Plant originally from Syria, Introduced in the West Indies, oil very fluid, used by watchmakers and perfumers.

Moringa apterU, Egypt.

Omitted: Chalmogree oil, India (Ggnocardia odorata) Arnatto Order, or Flacourtiaceae.

I did not mention a certain number of oils I found quoted in authors without the designations whether they are fat oils or volatile, and which I had not the occasion to examine; of several I could not define the botanical name. Such are the following :—

Nhan-pyai and Nhan-mai, from Moulmein. As we have yennal In Tamoul, noonay in Teloogoo, and unuay in Canarlse for oil, I conjecture that "nhan" means oil in Burmese, and that the first is coming from Myet-pyal (Afelastoma malabathricnm), the second Cassia ар. %

Kuniee oil, from India. I think sesamum = kunjed beiug the Persian name for sesamum.

Surgoojahoil, India[Helia*гЛшtannua., or sunflower), &c. I might have added many vulgar names, but this would have occupied too much of your valuable space, and my note is already rather too long. Happy shall 1 be if it should prove useful to Боше readers of our English Mechanic.


P.S.—I intend adding a short supplement in the course of some weeks. Five or six errors crept into my first note, full of foreign names. I beg to correct the following, botanists will easily correct two or three Datin names:—1. Palm order: "Klrin nut" read "Kirlu ant"—5, "Hoerve" read •'Hoeroe."—16. "Cumelini" read "Comellne."—18. "Beral" read "Béraff."

В. (To be continued.)

GALWAY, MAYO, AND SLIGO. Sir,—The enclosed paragraph, cnt from the Limerick Ckronicte of June lGib, may interest some of your readers about to take a tour through Ireland. I am familiar with some of the places mentioned, and would recommend them, when in Limerlck.^to visit Castle

Council, Killaloe, Plassey, Ac, and then to take the steamer dawn the lower Shannon to Kilrush and car to Kilkee (8 miles), the coast scenery of which and adjacent places, will amply repay them the trip. They will Hud excellent accommodation at Moore's, Shannon's, and Walsbe's hotels, or at Sampie's, at the east end of the town, a less expensive one. I can recommend the Clare Hotel, or Cruise's, in Limerick. Should they wish to remain any time at Kilkee, I can recommend them to apply to John Koche, a worthy retired coastguard, who will assist them In procuring apartments or lodges. It Is rather early for a visit ro Killarney; the autumn, when the foliage is changing, is considered the time to see It to advantage.

C. Townley, The Turret, Ballingarry, Co. Limerick. "Now that a magnificent touring season is approaching, intending excursionists, whether preparing to buckle on the knapsack and grasp the stout oaken stick solo, or in parties, are anxiously looking out to select an interesting locality as the scene of their rambles. As regards the inhabitants of this locality —of Clare, Limerick, Cork, and Tipperary—the entire south of Ireland has been everdone. There is scarcely a waterfall or a ferny nook, from the Slaney to Dingle Bay. or from Crook Haven to the Shannon, which has not been over and over again invaded by the feet of Bight-seers. The beauties of the Blackwater are known to almost every one, and even exquisite Killarney has to be ransacked in search of new scenes of loveliness. It is to be deplored that while Ireland presents so many attractions to the tourist, that people will leave hor shores and prefer seeking in Wales and Scotland scenery far less gratifying than can be found at home. Windermere, fascinating as it is, can never compare with the more awful beauties of the Kerry lakes, and nothing that North Britain can show, emulates the graudeur and sublimity of the terrific gorge of the Killeries. Apropos of the Kllleries and ol that interesting county washed on its southern shore by the bay of Galway, and on the weet by Clew and Silgo bays, and which stretches out to the north by Lake Krne, there is no district of such limited extent so fully capable of gratifying the curiosity of the traveller, or of satisfying his utmost cravings after new and beautiful scenery. The counties of Galway. Mayo, and Sligo, have been hitherto almost a terra incognita to us southerns. It was so tedioue and so expensive to reach their scattered beauties that more time was expended in paying a visit to Lough Corrib and Connemarra, than would bring the tourist through the different points of interest in South Wales. Fortunately all these things are now removed; the opening of the railway communication from Knnis to Athenry, brings within a few hours'run of this city the starting point of as Interesting a tour as could possibly be devised. Fortunately, too, the tourist

meets facilities along his route which are not to be met with elsewhere. The Midland Great Western Railway Company, in Its arrangement as regards time and fare, enters thoroughly into the requirements of the excursionist, and gives every opportunity of conveniencing those who travel along the lines under its control. The knowledge of this fact alone should fill the County Galway and the surrounding countleawith tourists during the coming summer months. The trip to be sketched ont for the tourist should of course depend upon the time at his command. The picturesq*uc city of Galway should first be reached, and If possible the romantic islands of Arran, abounding in Interesting ruins and covered with rare ferns, visited. A sail up Lough Corrib, either as far as Outerard or to the beautiful village of Cong'at ita northern extremity, must next claim attention. If the former place be stopped at. the visitor cau at once proceed through the western highlands and enjoy oneof the most delightful drives it is possible to conceive. Bal linahinch, celebrated for it« marble quarries; Cllfden, for its natural beauties, are successively reached, and a short tramp to the north of Clifden brings the tourist to the pass of the Killeries, one oí the most gloomy and terrific pieces of wild scenery, mountain and ocean combined, that the British islands can produce. Clew Bay, with its thousand islets, is marvellously enchanting; and Indeed along this stern coast, almost at every headland, somo new feature wild and wonderful, meets the astonished gaze. If time should not permit the tourist to proceed beyond Westport, he can return by rail to Athlone, or, better still, if he can prolong his rambles, he can, pursue his course still farther north until he reaches Killala and Sligo, in which case his homeward route should be via Mullingaron the Midland Great Western line. This excursion, which Includes most that is beautiful in the western highlands, might well be performed in from seven to ten days, and a tourist, who unites with a love of mere scenery, a taste for the beautiful in nature—the ferns which are bidden in wild mountain gorges, tbe heath which cover hillsides, or the singular geological features which present themselves continually before him—will find himself amply rewarded for his toil and travel."

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Tnteknally Geared Lathe.

hole»—Tii.» 360, :;36,300,144, and 96. The other side of it Is an internally-cut wheel of 60 teeth. Figs. 3 and 4. Toi» wheel gears into two wheels of 12 teeth, H and I, fitted upon the disc В. Figs. 5 and 6. The pulley С is of cast Iron, and is bored to fit the mandrel easily, and is capable of revolution on it. On the projecting part of the neck of the pulley (Fig. 7) there is a plain part turned, over which the caet-lron diso В, is fitted loosely, and beyond this again is a email wheel K. of 12 teeth cast, which gears into the wheel I. D is a fine screwed nut, that binds the whole arrangement together when in single gear, and G is a hinged catch that is fitted into the headetock, and when raised falls into the notch J in the disc B.

The action is as follows :—When in single gear the pulley and all its parts revolve as an ordinary one. the catch G U thrown out, and the nut D is screwed home. When the slow motion is required, the catch G is raised into the notch J, and the nut D Is slacked back about H or '¿ turns. The lathe cora being upon one of the grooves of the pulley C, revolves it", likewise conveying motion to the wheel К on its neck. This wheel turns wheel I, and I gears into H, which turns the internal wheel A. aad so produces the slow motion by the difference of the number of teeth in the wheels К and A, which in this case is as 12 is to 60, or as 1 is to 5. The catch G is likewise very useful for blocking the mandrel stiffly (as in unscrewing a tight chuck i; and as any part of it can be brought into position as regards the notch, it can be blocked in any part of its revolution by slacking the nut D.

These drawings form full working drawings, being strictly to scale, 31n. to the foot.

G. W. A.

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The operation by flve-flgnre logarithms would be quite sufficient.

* The geocentric longitude of Venus computed from Right*Ascension326°5l'Ö85, and declination 6U 4' 11* S. is found by the first formula to be 326° 59' 47* 9, or 26« W 47"-9 and its latitude 6« 51' 22» 5 N.

Using the last formula, and the logarithms to five planes only, we obtain the approximate result 26e 59'8 for the long, and 6° 51'4 tor lat. Please show in tho eliminated formula how to distinguish whether the lat. is N. or S.

In the " Astronomical Notes for June" it is stated that the moon will be In conjunction with Mercury at 49m. past ¿a, m on the next morning; "a.m," should have been left out. Mars is in conjunction with Jupiter at lh. llim. on the afternoon of the 27th, 7h. 12m. is therefore an error.

There is not given any account of the rising and setting of the planets for this month.

Seeing that astronomers agree to compute from the

first pointof Aries, why do they not say that J upiter is in Gemini, Uranus iu Cancer, Ac, instead of Celling us that the former is in Taurus, and the latter in Gemini, Ac.

If they Intend to adhere to the ancient division of the Heavens, why do they make their computations from the point to be determined by the precession of the Equinoxes?

G. Firth.

1 ' MUSIC. Sir,—Mr. Traylcr (page 332) has earned the hearty thanks of "our" musical reader», in defending the sol-fa method, which has received some " hard hits" lately in your Answers to Correspondents. 1 can fully endorse what he has said respecting the advantages of this easy, cheap, and true system, having had the drudgery of teaching by several methods for the last twenty years. Let me state for the benefit of those who wish to sing correctly and easily, that I lately took a class of village boye, from seven to nine years of age, who, without any previous knowledge of music were able to sing ordinary hymn tunes at sight, after six lessons of half an hour's duration. Now if any of our readers can show me a '* more excellent way," I shall be most happy to learn, and they will be deing good service to hundreds of others, by making it known in "our" columns. There is just one part of Mr. Trayler's letter, with which my experience will not permit me to agree; he says, that this method will teach pupile to sing in tune better than any other. I have always found that singing out of tune, is the fault of tho singer's ear. and cannot be ascribed to any method of teaching. I am of opinion that no amount of practice will cure this evil, so trying and unendurable to a good "ear." I may add, the tonic sol-fa system number its adherents by tens of thousands in all parts of tbo civilised world—wherever there is competition, it is never in the rear—and is now too firmly established to be shaken by the prejudiced opinlone of old notationlsts.



Sir,—If I, during the summer, go to Cornwall, Wales or Westmoreland, and wish for authentic Information regarding the vicinity in which I may find myself, how am I to get it? X doubt net but many of your readers, if I knew them, or they knew me, would be pleased to offer their services, and teil me exactly what I wanted to know. Many others, situated exactly as myself, would gladly hail and reciprocate the kindness thus given. Could uot some of your readers give their names and addresses, the time they could receive "calls," &c, thus. "H. B. 4 a.m.," " T. it, 8 a.m., 4 p.m. Any travelling English mechanician calling at these hours, would receive a hearty welcome, trustworthy informatioa regarding lodgings, remarkable places, and general charges.

С H. W. B.


8ir,—If you should thiuk it worth engraving, I enclose a plan and elevation of a velocioede, the best I think, the querist (4097) can have for the purpDses he requires. It is four-wheeled, and has a broad seat for

frame, having a socket in front for a steering fork, very similar to that of a bicycle. The cranks are set on an improved plan, which obviates the well known "dead points," and ensures a continual application of power—viz., the cranks for one rider are ectoroseways with those of the other, as may be seen on elevation. The seat must be well stuffed, and there is no need of springs. A three-wheeler would not answer.

Bicycle Maker.


Sir,—Several of your correepondente write about cutting book edges. I enclose a sketch of how I cut them. It is with a chisel, which when sharp aad pressed


on the top of the press, will cut them as well as a proper cutting knife could. Will " A. B.,'* or any other correspondent tell me how lo clean dirt» such as finger marks, &c., from the leaves of books before,binding?



Sir,—I like the letter uuder the above heading in your last number, because the writer exercises the Englishman's privilege of growling like a man, and admits his consciousness of the row he is making. Seeing, however, that his requirements range from mathematics without symbols, up to slide-rests of the thirdorderof complication, and considering the great variety of subjects touched on In the letters you publish,. It does seem odd that he does not more frequently find something to suit himself. May I ask him if there is any subject that he has ever heard of, about which he wants to know anythiug, and will not get a prompt answer about in the English Mechanic, from some one or other, if he will only take the trouble to say what he wants? Also, now that he has got the drawingr of slide-rest, ot what possible use it can be to him? Not to make one by for sale surely? Who weuld buy it if he did ? for although Mr. Evans gets £6,5 apiece for them, 1 think one of his would be preferred at even that price by any body wanting one. Also, I wish to refer "Blacksmith " to two letters of the " Harmonious B." iu Vol. X., one on forming steel mandrils, and the other on building a lathe under difficulties, and to ask whether such letters are not, as It were, specially for the class to which he belongs, although the information may not be what he individually wanted at the time 7

As regards se If-teaching, It is oae of tho most laborious tasks possible, though there are plenty of helps for the purpose published nowadays, without any more being written, and in writing those helps, the difficulty is to make it easy enough; just as in drawing up an examination paper, the difficulty i« to keep it down to the level of the knowledgeof the pupils, not to puzzle them with hard questions, which some folks look on as evidence of sharpness on the part of the examiner. But that men have taught themselves even high mathematics, was proved by my old tutor, James Hann, of Ktug's College, London, who was once a pitmau at Newcastle, and had charge of the windingengine at the pit-mouth, and worked his sums with chalk on the end of the boiler! und in those days there were very few rudimentary treatises to helpaoy body. He tried astronomy first of all, aad when he found ho could not understand it from want of knowledge of mathematics, went back to the beginning, and never tired till he had learned it all, and made the best of masters, beoause, having laboriously gatnedevery step

on tho rond, ho was so perfectly grounded in every part of the-subject. As to French measures. "Tllnrkemith " has only to recollect that a millimetre is just

about — oí an inch, во he has only to prick off a scale of

25 25 to nji incli. or inore accurately, 100 parts in 3« 4in and measure hi« ruleon that scnle, the number of millimetres, given. 1 quite vgrrc with him, that to rush off to some book, ami lind n wmula ready made for ttio job, and put the valves in for iho letters, and stir them op till a result comes out, is not the way to answer a question to ths satisfaction of a practical man; and it Is the way only too often adapted by cortainof youcorrespondents. It is like copying out a recipe with out beiug able to write •• preved" after it.

J.K. P.

A CUMBERLAND MINER'S APPEAL. Sm,—In answer to "A Cumberland Miner," allow me to suggeet two methods of preventing those terrible explosions he mentions :—1st. Go to a clever blacksmith, and get brazed on to the end of the pricker with a slanting- splice-a piece of copier a few inches long, so that it will enter the powder.aud not the iron end of the pricker; but il the powder is likely to ignite even after tho iron pricker that is now in ueo is drawn sufficiently out to be above t'<e powder then I suggest (2nd) that u brass tube flu. internal rtiam., and the proper length (and я piece Sit. Ion" can oo got at Birmingham for about 6d. or Sil.) llave a piece of round rod iron f dtani. driven into It to within an inch of one end, w hich end may have a piece of brass or copper soldered or brazed into it, and pointed off to imitate the pricker at present in use. With such a pricker, tne rammer, if it struck the pricker when the miner was ramming on the powder, would not strike a spark or Иге, and the pricker would not bend like copper.

H. W. A. S.

Sl,R.—bet я "Cum°erland Miner " take lib. of hog's lard and 2oz. of finely-powdered rosin, mix them at a gentle heat, and when using tho pricking rod, smear a piece of paper (such as our Mechanic is printed on) about, 2in. wide, and vihateverjlength the hole may be, twist it wlthaslight spiral direction round the rod, and place the hole in before tamping, and after the hole is stemmed or tamped, the rod will withdraw with safety. To thoroughly test the above, place a piece of the smeared paper on a piece of flint, and strike with a steel, and it will bo found utterly impossible to obtain a spark, where thepaper covere the flint.

W. W.

Sir,—A« I understand tho "Cumberland Miner,' the operation of Masting is as follows I—The hole Is drilled in the rock, the powder inserted, the pricker placed in tho hole with the point in the powder, the hole к then rammed fnll of earth, &c, and the pricker withdrawn, levving a small hole for tho Insertion of tha fuse or straw. The dangerous part of the work is withdrawing the pricker, as it may strike fire from nibbing against Ore rock.

Now, I have heard it asserted that ramming the hole fall is quite unnecessary; that a wooden plug driven into the mouth of tho nolo is much more effective.

This would appear to be correct according to theory for it is well known that a gun barrel which would bear very heavy charges of shot, when rammed down on to the powder, may be burst by iusertlng a cork in the muzzle before firing.

If the " С. M." wonld try the wooden plug and report the result. It would be Interesting to your readers including'

O. H.


Sir,—Having rend the letter in vour last number, concerning tourist!' trips lu Ireland, and finding- that you are willing to insert further communications on the subject, 1 beg leave to send yon the following.

Donegal is well kuowu as the most picturesque county in the North ol Ireland. It is full of high mountains,and small romantic lakes. The Atlantic Ocean on three sides washes its grand and rowed shores, and many beautiful inlets penetrate farmland. As I am perfectly acquainted with the county I can with confidence recommend the following tour as one that will repay the small time and expense necessary. I suppose a traveller to reach Belfast curly in the morning by tho steamer from Liverpool Harrow, or Fleetwood. After rest and breakfast at the Imperial llotel, proceed about 9 a.m. by the Northern Counties Railway to Portrush. The omnibus of tho Antira Arms Hotel, one of the best in the North of Ireland, is waiting at Hie ttatiou. Spend that afternoon in a ramble on the rockv Dromon Head and on thebeach, which is only equalled by two others in Ireland. Next morning- visit the Giant's Causeway (bystage from the hotilî und the grand cliffs beyond Boats are always to be had, but if you object to rough water you can see almost asniuch by laud. Sleep that night also at Portrush. Next morning take a car to Portstewart—3 miles, and there (for I address predestrians) begin your walk, keeping along tho shore till you roach the mouth of the liiver Bann, which you will cross by a ferry. Still keeping by the shore you will reach Hngillignn. which is at the mouth of Lough Foyle. Cross there by ferry-boat to Greencastle—2 miles, ami you are in the rugged County of Donegal; walk from Greenrastle to Carndona^h where you ought to spend the third night. Next morning, walk from Citriidonn£h to Buncrana, ascending Slleve Snaght Mount on your way, which is more than 20!i0ft, high, and commands a magnificent view All that day's walk la most picturesque. There is a large and comfortable hotel in Buncran». Next day tske the rnil from Buncrana to Fnhan ana there cross the beautiful Lough Swllly to Itnthrnullan, thence by mail enrtto Letterkonny, where you would spend the fifth night at Hegarty s llotel, a very clean and comfortable one. Ti your time is short yon can end your journey here, and go by publie stage next morning to Strabane in time for through trains to Belfast and Dublin. Bnt if you have 3 days more, by all means wait, and taken post ear from Letterkenny to Glen Beagh, the most, benutiful spot in the county. You will also pass Gin-tan on the way, whiehjs only second in scenery. At the lower end of Glen Beagh dismiss your car, and walk up along the beautiful lake, which is 3 miles long, lying between precipitous rocky mountains. If possible, get an active little boy to guide you across the mountaius to the Pisoa Glen of Dunlewy. While crossing this pass, you will obtain a truly magnificent view. Below you are the Dunlewy lakes, and beyond them Erigal, rising precipitonsly the highest mountain in Douegale and in the North of Ireland. Descending, and passing Erigal, make your way to Gweedore Hotel, and spend the 4th nln-ht there. After which you enn either (1) spend a day*at Gweedore, boating, fishing, and ascending Krignl, for which last you shoull take a guide; or (*> go by mail car to Dunfanagbynnd spend a (lay there, ascending Mucklsh, or exploring Hornhead; or (3) go hy the same mail car through Dunfanaghv to Letterkenny where your jouruey will end. Let me add, that if a Sunday should occur in your tour, you will find I onrush or Letterkcuny the most agreeable places to spend Hin, as they have the most comfortable hotels, the various places of worship close at hand, and the opportunity of pleasant short rambles in vacant hours.

I write without the opportunity of eousultiug looal sources of information, or would add distances, times

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■ind it is very little the worse for wear. We tíave а sihclous grit во full of fire, that to use an iron pricker would be exceedingly dangerous; houce tho use of tho copper one. My beater or stom-rod is much thicker tor an inch at the lower end, with a groove in It made with a round file, to admit tho pricker. I preserve tho <lust that comes out of the hole during boriug to stem with it or plate. Having bored the hole, I put what powder I think sufficient Into it. Having slightly greased the pricker, I thrust It to tho bottom of the powder, and put some paper on it to prevent any fire igniting it. After stemming 0 or Sin., I slightly draw the pricker, and so until the hole Is stemmed. Care must be taken to keep the pricker straight in the groove of the beater. Attending to these directions, яо accident such as he alludes to need be apprehended. A Yorkshire Lead Miner.


Sir,—Your correspondent " Beta" suggests that in formation regarding food must prove useful, especially if attention can be drawn to any members of the vegetable kingdom, whose properties are not generally known or understood.

Acting on this, I will draw your readers attention to a vegetable, easily grown, aud much used on the continent, but scarcely at all In England—I mean the gourd or pumpkin. Its culture is the simplest. On a small heap of manure or leaves, or anything which will give a little bottom heat, sow one or more seeds ot the mammoth gourd. This, with an occasional watering, will produce Irultol upwardeof 50or6olbs weight. As a proof of this, two were exhibited last ycarat our local fiowcrshow, which grew on the same plant, and weighed respectively 87 and 42 Iba— lu» lbs,. from one seed. At unothor show were exhibited seven which weighed together 413 lbs.

They are most excellent fired for man or beast, either in soups, pies, or boiled as a vegetable, and as they are not gathered till ripe, and then hong up in a dry place, and a slice cut out when required, they are useful all through the winter. A packet of seed, price fld , can be had of Messrs. Suttnn, Heading. It is rather latí, bnt I hopo some of your readers will try them this season, and state to you the result

W M, G.

i. Let the intending tourist by all 'The Highlands of Donegal," M

all means

admirable book, writteu by a native of tho couuty. I shall now only add two hints to travellers, 1) that it Is necessary to ascertain particularly where you can got a good bed and breakfast, for Donegal is out of the beaten track for tourists, and you cannot count upon these; and finally, that a weary predestrian can at auï ÏÏali town »iTM »post car, at (id. a mllo for one. and 8d. for two passengers with a gratuity to the driver of a fourth part of the fare.

H. S. L.

SQUARING THE CIRCLE. Sir,—In the curreut number of our journal, is a very funny letter about squaring the circle by practical geometry. If Mr. Arthur Gearing starts with the parallelogram aud divides it iuto cuneiform pieces, as represented, he will uot be able to mako a circle of them, but a polygon; on the other hand. If ho starts with the circle he will uot be able to make a parallelerem but a figure with wavy or serrated edges; It puts me in mind of the carpenter's mode of measuring the circumference of a circle by means of a piece of string. r

T. Cooke.

Sib,—Mr. Arthur Gearing deserves great credit for his ingenuity, if not for his success, in his elaborate effort (No. 2ГЗ, p. 301), to solve, even practically, the unsolved problem of "squaring the circle." Mr. G.'s diagram presents certainly the nearest Mular solution of tho great mathematical puzzle. Having nrrived at this conclusion, It seems strange that tho Ingenious discoverer did not attempt to с own his work by connecting his diagram of '■ practical geometry" with a regular geometrical démonstration, proving the perfect eqnality of the relative areas of his circle and square. Had he done so he might fairly be entitled to an "lo. lo. triumpho" in the columns of the bNC.Lisii Mechanic. It does seem a ruthless act to demolish Mr. Gearing's " practical " or rather uuclvmicul, geometrical square, but the Interests of science demand it. If a square be " a four-sided figure whose sides are equal, and whose augles are right augles." Mr. G.'s square is renllv no square at all. foi two of its sides are not rectilinear, and, therefore, not equal to their opposite sides ; they are a series of cwreu - sec

tions of tho circumference of the circle Mr I transforme 3« sectional curve lines into a contln'uoia lineas a side of his square I and ho Introduces I similar series of curve lin es into the area of Ms square in contact with each oilier, so that it would amWr ?h*?í° "?cuI»r demonstration." if correctly drawn' that a scries of blank spaces remain unfilled, the coneequcnceis, that the area of the square 1» con.l.lerablv lurger than that of the circle. Mr. G, «tteruroTto tupport.his demonstration by a reference to the YIV

vluch ,Ш1 he <aual to a five,, rttUmear Л,мге Cíii* proposition cannot possibly apply to Mr. Gearing's conversion of his parallelogram (F%. 2) inio a square (No. 3) for the very obvious геавоп. tb»t his parallelogram is not, aud cannot be made Into a rectUinmeligure, no more than his square, because the sides are composed of 31 curved lines each. KitherMr ft deceived himself or ho was uot honest, in reducing these curves iuto straight lines, r-d In palling a falsi parallelogram and square upon the readers of the bNGLisii Mechanic, aud in attempting t« establish his solution of squaring the circle by an unjestiiiahle reference to Euclid, It is to be hoped that Иг Arthur Gearing will be more successful In his next effort to (five an Interest in the study of practical geometry by the mere exercise of ingenuity." Wm. Arthur Darbv, M. a... F R A s Chorlton Hall, Manchester.

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scicntiously given to so simple a question on so Important a subject and one that involves so many considerations. When 1 answered the question at ar 1 had a fourfold object In view. Tho first was raise this ghost, or the subject I would thoroughly disturb It, во that it could not again until it had received Its due. The second ■ to show the folly of asking for advice without etat, plainly and fully all the circumstances bearing ut tho case, and the danger of giving It also. The tl'i was to show the "lads" a stumbling block over which they might easily flounder-" Factory Lad" saw ttfle My fourth was to c»U forth answers from otter readers that the subject might be fairly haudled, ¡*d I had this object still when I gave my second answw. My motive may be ooen tecousUre for anything 1 know but I have papers by me here, In which I have tried to treat of the subject In as simple a manner as I could, to make it comprehensible to the " lads." and Vy the way, if any one will try to do this, he will find it no easy matter; neither can it be doue in one or two long letters, let alone short ones. I don't know how others find It, certainly, but I have to write write and re-write, before I can half satisfy myself that I Bhall be understood. But this is perhaps owinf to my inaptitude, as I am but an entirely self-tniT^ht factory lad, barring, that I took all the honours of A. Ii.-abs by a nine months' half time intendance at a sort of hedge school. I have been driven from my first intention by the very ghost I raised, and this week I am glad to see that "B. W. IÏ." has taken up one part of the subject In much the same way as I intended to do, if others did not. Now I fully made up my mind last we«, for "peppering " both " M. J." and H. C. S.," for what I felt to bo ungeueroue remarks. I cannot see what sonso there Is in any of ns trying to make ench other appear as simpletons, whether We do so by garbling or implication, when we are doing our best for each other, and for thousands of others. If " B. W. R." will refer to page 331, at the top of the middle column, ho will sec that he is mistaken—I hope he will kindly acknowledge. With respect to the two last letters of "H. C. S.," in which he refers to me, I protest, in the words of a country lad, "ageanst ho'din' balls whoilst other fooaks whollops um." But as soon as ho has satisfied me that there Is no " chaff" intoaded in his last letter, I will give it due attention. I may sere say, in explanation of what I said about putting tlu cart before the horse If he intended it to go, that I wished to Buggest by what 1 eaid, as I thought It was opportune, tho vagueness of the word " draw," as it implies something like attraction, whereas mechanical motion is communicated by impulse, or pushing; hence the horse pushes the cart before it by ineaue of the collar on its shoulders, &c. In conclusion, I hope this epistle will do something to appease the wrath of the ghost I have raised, as I raised It with a good intention, but it kicked up a greater floundering than I bargslued for, when I considered what littlo attention the subject of cotton ea-inning hn<l called forth from correspondents before, and I havo boon a subscriber from the first number of our paper. "B. W. R." says I appear to have lost one end. I hope he, " H. C. S.," "M. J.," and "Factory Lads," ad Hi., will try and prevent me from ilosing the other end. The " cotton panic" taught above one lesson, and I will give the results of experiments if others will do tho same.

E. Slater, Burnley.

Sis,—Putting aside the preliminary remarks of "B. W. lt.," in last week's paper, let us at once come to tho question. Is It proper, in taking the draught of a carding engine, to begin at the feed rollers? I say yes, and that the rule disputed is correct in that point. "B. W. IS." says no; you must begin at the lap rollers, as there is a draught between them and feed rollers. My advice is, begin at the feed, and end at the delivery rollers, except you want to see whether there really ¿s a draught between lap and feed rollers. If there Is, get it altered at once, as it Is a greater evil than it is a bcueflt to give the slightest strain to a lap. If the rulo I give is uot correct, then all the authors I have studied are all wrong likewise; for I never found one yet who commenced at the lap rollers to take tke draught. And yet they undoubtedly would have done

f-o if they had any Me* that there was one; or if they had thought a draught at all nuouwsfiry.

"B. \V. ÏI" Isju*t confounding theory with practice in hie aualysis of my letter last week. 11 ho does, he will rind th -m (in cotton spinuiugespeciallyj very awkward fellows to deal with. He foruets wo were dealing with the former, not with the latter, lïut even looking at it In the same light that he does, how docs ho account for a carditis engine working with the same arrangement I quoted, with rollers covered with fillet Instead of bei up; ÜuteQ? Now, If топ am does "happen to be acquainted with the iuakeof the engines 1 took my figures from," he mast bear in mind that machines do not always remain in the ваше state as that in which ttiey are" sont out, especially where there is machine making combined with cotton spinning, as in my case The particulars I quoted last week were from one of Walker aud Hacking's singlo carding enginee, the only one wc have. He is wroug in his etuteuunt about the length fluted rollers will take up— at least iu my case. I lim aware it is a common custom to have very deep Ilutes cut in the feed roller«. Now, ours have not; consequently, there Is very little difference between the theoretical and the practical result* of the length taken up. In fact, what slight difference there waa I got our carder to counteract it last week by nailing thin slabs of wood, ¿in. thick, round the lap roller, making it samo as some of our other (Walker and Hacking's) double cards, the lap

Ц 48 rollers of which are f>Un. diam. — x — = *90

14 6* In his illustration of the piece of string, does he mean to say that it would bag if it had a support in the middle same as a guide pjate to a carding engine? If he will take a piece of string, aud hold it tight (not extra tight) between two points l'-iin. apart, I am afraid that neither he nor anybody else would be able to detect the slightest bag in the middle. Neither would he in a lap at that distance, If it is taken up as it ie delivered. The result of what ho says last week just amounts to this—that the draught uf a curding engine should be taken from feed to delivery rollers, as at lirst disputed ; for if you begin at the wheels on the lap roller, as In my case, it doee not alter the theoretical result one jot, and thut is what you arc dealing with. "B. W. R." says he does not consider his argument answered by what I explained. Well, I cannot help it, but I am happy to say mino ie. I am much obliged to him for his kindness in giving me the recipe for size, aud alio for hie information on yarn teeters, t heartdy endorse all that he puts forth in hie first letter, last week, on the draughts iu drawing frames. In which he displays his thorough knowledge of the subject. It is really more tbau 1 cau credit him for with regard to hie petideae about the iudispousable draught between lap and feed rollers.

I now take my leave of this subject (oxcept some moro forcible arguments can be brought to boar upon it), as 1 do not think I should be acting right by keeping up this "Hinple" matter, when my frieud "B. W: K." thinks 1 ought not to do so.

The Harmonious Cotton Spinner. P.S.—"Will *' B. W. R." kindly give me his opinion on the yarn tester he mentions—the range of strengths it will indicate, and the principle on which it works 'r


Sir,—Mr. K. Davis, on page 278, in hie description of «ilk bolters presently in use, asserts that there is not more than one-third of the silk in actual use, the rest being taken up with raits and ribs; this may be the case with some silk bolters, but certainly not all, as the firm of Thomson, Wilson, Wcildel], and Parllck, have been putting up silk bolters for the last six or seven years that have noue of these cross ribs to which he refers. The rails are ij* x 2", and the whole space covered by these rails is not more than VI" iu width. The circumference of the bolter ie У 4"; deducting 12* from 9' 4 leaves 8' 4' of silk for effective use. 1 have seen one of these bolters 23ft. long, dressing with ease to G pair of stones.

An Onlooker.

Sir,—I believelweehall.havetotakc *» hat " A Stonoman " persists in sayiug toachiug.hie "blindness," Im

Eracticabillty &.c , to be perfectly truo. He eaye that e is so blind as tu bo unable to conceive why the lespective density of the various materials which composée a millstone should disturb its etuudiug balance, when it becomes to run. Ouo would imagine that enough has bocu said oa the subject to show anyoue the reason why -, and to illustrate this f suggested that he should try to do so by the uid of Chirk aud Dunham's patent balance, which f understand he has in his stones. From such suggestion 1 gather that he understands me to have recommended those balancee, which is not the case, though 1 believe with С M. that there is no better if properly used. But to a man with his wit* about him the same results can be obtained without them. Forinstuuce, if John Botting had sank his balance box deeper, instead of transleriug hla shot from one boxjinto another, both balances would coincide. I would advise him to try It. The reason for so doing is that it briugs the weight within the ваше horizontal line as the object it has to counteract, and here is the advantage of having the patent, because of its mechanical arrangement ; by the aid of which "A Stonemau " says that it Is improbable that a stone's standing balance cau be disturbed. If he had only giren the experiment a practical trial, it would have added considerably towards Illuminating his "unenlightened intellect." He1 веете to think that I Ignore a standing balance. Why ho should I am ut a loee to kuow. No one is more in its favour than myself, yet in poiut of utility, I regard it as stated in a previous letter. But while it ie possible by mechanical means to possess both, no one would be satisfied with one only, but this cannot be accomplished in any other way than upon the principle stated above, aud the best method of driving the stone while balancing ie that stated by myself in a previous number of the English Mechanic. Ah to his etones doing equally good work before ho had the patent proves nothing more

than that they were in a good balance, which \* ронtíible to arrive at without it, as stated ahove. But "Л Stoneman" says that the fault, or cause of the two balances Is elsewhere, viz., cogs, irous, faces, Ac. Permit me to чау, most respectfully, that he is under a very grave del us Í ou if ho really believes what the says is true. But to settle the question by practical experiment, once and for ever, let him take a pair of stones from the hands of the makers, and face them as trucas they possibly can be. Lot the most perfect irons of any kind be put in them, let the bidstono bo perfectly level, let the neck aud footstep be as tight as they possibly cau bo. consistent with nouliabilty to heat. Let the driving wheel aud pinion bo perfect models of truth ; give the runuers perfect standing balance, bring it up to its proper speed, and he will Und it out of balance while thus running. If not, he wili be kind enough to forward the result to the English Mechanic. In his last letter ho tells as that ho knew stones being allowed to run empty whilo the mill could be stopped, kicking violently all the time. If such a thing has ever occurred in hie presence, I say that both himself and the spoutsman were much to blame. He also says that a different face is the cause of the stones' balance, altering every two or three dressings. Is it not rather a slight deviation in the centre of suspension caused by wear aud tear?

Тпомав Evans. [We have omitted certain offensive remarks from this letter/which if inserted would have irritated the correspondent alluded to, without producing any corresponding benefit. Wc are sorry after what we have said that we find it so difficult to discourage ¡кзгвопа! reflections and unnecessary hard hitting iu dome Of our correspondence.—Ed. E. M.]


Sir,—1 will add a few more remarks towards the discussion of principle* denied by Mr. Jordlnc, aud to endeavour to carry readers' minds somewhat,beyond the very narrow bounds to which "F. W. M." would limit them.

I think it can be best dono by supposing a caso. In France aud England there is a party protesting against the Treaty of Commerce as injurious ou exactly the gruuuas taken by " F. W. M." although this treaty is really an approach to the coveted reciprocity; our silk manufacturers and their cotton manufacturers declare they are being ruined by the competition the Treaty Iklh engendered, and the case I intend to suppose is, that these complainte aro in both instances correct. Well the nurrow view,- and that which the interested persons take, is of conrso that this is au evil to be arrested by some limit to the competition, The wider view is that tho buyers in both cases have to be considered, and that all are benefited by obtaining what they waut, and that the true remedy ie for the unprofitable work to be given up aud exchanged for the other ; that is to say, the French should make the silk, the English the cotton, aud each exchange their surplus for what they require of that which tho other cau produce heat.

Nothing but narrow provincialism, the Idea that our owu particular spot of earth is of most importance, prevents this truth from being seen and acted oa ; the narrow view Is only a relic of tho limited *' natwual * feeling which once made England aud Scotland enemies, and at one period saw seven) distinct nations in England. The wider view is that which teaches ue to regard all mankind as a common brotherhood, each nation really deriving benefit from what benefits the Others, instead of tho reverse, as Is so commonly supposed. 1

But "F. W. M."and his kindred will say as to our supposed case that the French would like to make all silk, but will not give up their cotton making, but put a fine upon ours to кенр it up, and then we must do the вате with their t-ilk because otherwiso wo must pay for their silk in money at a dead loss, and our supposed superseded silk mauufacturer must stand idle. Now here it is that people who can see just barely as fur as the tips of their noses fall into error. Nothing of the kiud would really happen. This energetic and industrious Englishman would simply say to himself, "Well I shall not be quite во stupid as my French friend," he would just make his cotton and send it to India and chauge it for Cashmere shawls, for which the Parisian ladies would bid him a high price, and with the money paid him for these buy the silk he wauted, and probably put Into his pocket a little "profit," our friend the " Harmonious Biacksmitli" to the contrary notwithstanding. Of course the caso supposed would never happen to anv single person as here supposed, but it ie what really does happen as far as the national commerce is concerned, and is just what ie meant by *' Herbert "and others when saying that commerce is really barter, aud that taking the average of years the total imports are wholly paid for by the total exports, tho higher nominal amount of the former being really the costs of (shipment paid abroad and " profit."

Of course "F.W. M."does not look for an answer to such suppositious as those in the early part of his letter; they eupposo the nation lu the one case a ruined pauper, and iu the other a retired gentleman living on his *neans ; both cases quite different from thUof an active business-like manufacturer and merchant, which is the actual condition of tho case of £uglund.


MESSRS. CUNNINGHAM & СО.'Я IMPROVEMENTS IN OBTAINING MOTIVE POWER. Sir,—A few weeks ngn you described and illustrated In your valuable periodical an invention patented by Messrs. Cunniughatn, of New Oxford-street, and McCarthy, of Bloom.tbury, for obtaining motive power as applicable to the propulsion of wheeled vehicles. Many inventors have laboured under the idea that a large amount of power may bo stored up iu spiral springs, and a vast deal of trouble and lose has been occasioned by this delusion. That invention seems to me to be thoroughly impracticable, or, as your able correepondent, Henry W. Revely, terms It, "nothing

moro nor lose than perpetual motion." Bait the /act of its being put forth by geutlemen so woll known iu tho mechauical world as thoroughly acquainted with all lis branches, it seems very curious that they should, if such is the case, have fallen into euch an error. The value of this invention, if practicable, will doubtless be exceedingly great; yet, not having heard further about It (a proceeding most curious if tho invention ie perfect), coupled with the aspect of the principles from which it obtains Its motive power, when looked atina scientific view, gives us grave cause to doubt ite applicability to tho purpose. Perhaps the Inventors themselves will come forward and put us right. I wish your journal every success.

A. Slvde.

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popularly stated In " Brewster's Optics." p. 41, and demonstrated in " Wood's Optica," p. 103: QF:FA = Q \: / Л. I fouud in using the instrument that there are two positions, and only two, of A between Q and q where equally good images of tho object at Q arelormed at </. NowQ </ = l**25 and F A = 3-6.

Required from these data, the two positions of A without algebra, i am afraid tho detailed solution would trouble the priutcrs, and might be refused space, which is weekly becoming more und more valuable. For tho present, therofore, I will merely state, that it becomes a quadratic equatiuu, aud the two roots of the uukuowu quantity, ti and 775, are the answers.

J. Steel.


Sir,—There ie one class of machinery which appears to have been entirely overlooked by your numerous correspondents—I refer to sugar mills for extracting the juice from the sugar canes. As this ie tho time whdu mills are being made to send to the colonies, iu time for the next sugar seasou, Г think it would not be amiss If wo now had a little information aboiiL them. I believe the only book published on the strength of sugar mills Is by Burgh. Jn it the calculations are all based on^the supposition that the length of the roller is equal to twice the diameter; but this, of course, does nut happen in the majority of coses iu actual praotice.

I should like if some of your valued correspondents would give some practical rules for proportioning the different parts, holdiug-down bolts, roller shafts, be.. also the pressure required to squeeze tho juice out of canes of au average ripeness. Information respecting breakages would also be valuable. As many of your subscribers go out abroad with mills, 1 am euro they would be delighted with any facts relating to their working, Ac. 1 am myself much intérêt»ted iu them» and should be pleased with auy practical hints regarding their manufacture or working.

Mac шматов.


Sir,—The device of your correspondent, Arthur Gearing, for squaring the circle, is ingenious, but it misses the accuracy necessary to a demonstration ; for tho wedges forming the circle being necessarily curved at the ends, cannot be arranged into a rectangular figuro without a " loss of material," which he hoe evidently omitted from his consideration.



Sir,—I beg to encloso you a rough sketch of additions to a bicycle different from any that I hav« Been in your columus. The advantages of the addition arc twofold—firstly, by the addition of the multiplying wheel A the revol ution of the driving wheel arc doubled without the necessity of moving the leet so fa>t as formerly ; and secondly, by the crank being attached to the wheel A, instead of the wheel B.nsis usually tho caee, the crunk is brought nearer to the saddle, which will allow of the driving wheel being made much larger than It is at present; for owing to the average allowed for tho length of a man's legs, tho distance from tho saddle to the cranks must in the present

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bicycle be limiteil to a certain length, or otherwise the

iT !£? wheel must be confined to a limited diameter.

I think that If my plan for increasing the speed, and that of Mr. Thomas O. Roberts for steering, were combined, the combination might make a very fast bicycle for a level road.

Should you think this sketch and description worthy of being inserted in your columns, your readers are welcome to the idea.

N.B.—Mr. Т.о. Roberts'»sketch appeared in the number of the Mechanic for February 12th, 1870.

W«. Jackson Pioott.


Si R,—Enclosed I send you sketch of a very simple kind of bicycle which I invented last summer, and intended l end it to you then; but I had previously sent a sketch for a spring wheel, and It was not inserted, во that was the reason I did not send the enclosed «ketch. But seeing in the last week's issue a bicycle '"v.ent,e<l by the "Phantom" Veloce and Carriage Wheel Company which was touching on the same principle as mine, I made up my mind to send it.

I can claim some very good features in it :—First, the very simple way in which it is made, as any one that can make a wheel could easily make the rest with the exception of the ironwork, which is not very much—only the crank, pedals, brake, saddle, ice


the total 4Hn. in place of 3Jin. Now I 1 |and 2
will show the position of eccentrics with Hin. E sq
N take 2,in. from 4Nn., of which it is the half, place
the eccentric where one I' d throw will be ex-
pended, with the crank at C, and the port will be
closed bin. or in other words It must be moved
forward until the valve is open to Jin. for lead, then
the eccentric is in the position shown In Fig. 1, El
which will have to be e Jin. more when the
engine Is moved in direction of arrow ; now If we
bring the rod Bl in contact with valve spindle A, the
valve will be J open as lead, but if we bring the rod
Di in contact with valve spindle, we find the valve
closed considerably; and to make the rod Di bring
the valve as atBi, we must move the eccentric E,
Fig. 1, to E, Fig. 2 ; thus we see the rods will each give
llln. lead, but the consequence Is fearful (perhaps
our friend В will explain it to our readers).

Again, I Baskervllle inks "the belief that the
middle of the link has no motion and should, if pro-
perly constructed have no motion as I say," now I
say again it should ml l the centre of that link is
in centre of valve spindle, and the eccentrics, Mr.
Baskerville says H I be; and as they are
shown in Flg3 our friend thinks the 2ln. involved by
¡he crossing of rods is communicated to centre of
Huk, Now let me disabuse his mind of so erroneons con-

Now, for Instance, the link being In centre of valve spindle, the rods will vibrate above and below the line of valve spindle A, thereby adjusting and keeping the centre of link as centre motion, and will do so so long as that centre Is in centre of valve spindle, but if we bring the rod In contact with spindle, we make that particular rod | give motion to the valve until the centre of link is brought to centre of valve spindle, and just the same with rod D, If we stand and watch a link at work, with the lever in the end notch, we shall see the centre of link vibrate; for this reason the centre of link for the time being is not the centre of motion, but the centre of motion will be found about 2in. higher up or lower down if the rod D be in contact, this is caused by what our friends | terms the crossing of rods, but principally by that


'W. T." (June 17, page 3M) it Is very evident that ,the lowness of the modern pianoforte detracts from its power at least in the bass strings.

Another difficulty Is to find a shape of case that la at the earns time saleable to the general public, and will admit of the greatest length of string.

1 enclose a sketch I have made bearing these two points in view, which I beg to commend ьэ the attention of "W.T." thinking,if itdoes notfulftltheonecondition of saleabfiity, it would increase the value of the i и» crûment ¡unusual point of view.

Alexandra. P.S.—Am I never to have my harmonium of the present with great variety of quality of tone, soft and loud. The a of the future of your correspondent "K. T."JuBtifles Its name, ami lie has never enlightened me on the points inquired about issue of March a

BOILER l l Sir.—I read an elaborate account in your No. Згг, written by " T. J. CO.," on l " Safety Valve." and In your No, 273 "J. Howell " gives his theory to calculate the pressure of the same, but in going through

which la not very troublesome to make. Secondly there is no danger of the legs coming in contact with the wheels, as they are enclosed in a box, which prevents all splashing or duel flying. You will see it seers from the centre, between the two wheels, which «re kept together by a hinge joint. The saddle spring can be made of wood or steel, the front end of which would be h.xed on an upright pin, so as it could turn and the back end would be loose, to give freedom for turning. The pedals would be greatly Improved if they were covered with indiaruober, which would keep the foot from slipping, and greatly lessen the

J i inff J° Ч1" feet- А°У other iElormation I will gladly give if required.

A. B. Handford, West Milton, Dorset.

LINK MOTION. f,R'—lamrmich obliged to Mr. J. Baekerville for \¿b{J way of treating of the link motion. He shows JU'\L no,reTer. not very exact on some points of tbf »Beam engine Ariz., lap lead and link motion.

bow\ if Sir. Baekerville was well versed in link niotion.\he never would have said what he line, viz. • that tlA whole amount of vibration must be com- mumcateoV to the centre of link" This assertion I "Ч"": "ÍV n<" icorrect, inasmuch as the centre of link is never expected to transmit any motion to the valve ; I do not deny that the centre of link does move when at work with the lever at either end notch, but this I do emphatically deny, that the centre of link will vibrate when that centre is in line with valve spindle and crank shaft, and the diametrical centres are in opposition to each other, no matter at what angles they stand with the crank, because bo* eccentrics should have one throw, consequently both travel one distance; and at the same speed, butin opposite directions, thereby making the link centre the centre of motion for each end. •Iiow.,1.?t TM.e, take Mr- Bnakerville's supposition viz.: "Mm. of lap aud Jin. lead and multiplying by 2 gives us 3¿ln." which he ■' says is the proper amount" but there lie Is wrong again; because we must have more vibration to open the valve Man. more, making


particular rod that is not engaged; being 16in. below
the centre line of spindle, thereby receiving all the
angles, and causing that end of link to have almost
double the vibration, and would make the link into a
common lever if the 4\ of vibration given out by the
Mt] wll,íh throw" the centre of motion as shown at
Г *"■ ff- '' Bl яш1 Dl "hows eceentric rods when

lever is in centre notch Ri D3 when at end notches ; the
same with Fig 2; the full lines in Fig. .1 represent«
the rods when the crank is at С В, С D, and l a пчпес-
tively. '*^

James Harrison, Hyde, near Manchester.

Sir,—After reading the clear statement of the dif-
ficulties in piano construction by your correspondent

the latter, I find there is a mistake In the subtraction.
The figures 419. 4910, should be 409, 4910. This throws
the remaining part of the calculations wrong. But it
strikes me that "Templeton's " way of calculating
this valve is much more simple than either of the
above, and if you think It worth while to insert It In
your columns, I herewith describe it. Take a light
line at the centre of valve B. which is 3* from A, the
point of resistance, and hook it on to a Salter's spring
balance or steelyard when the valve is connected to
the lever, and supposing the weight to be 351b., this is
the effective pressure against the steam at the orifice
of the valve, or=51b. per square inch, the area of
valve, and then by adding the weight of a ball, 151b.,
which with weight of lever and valve will equal 201b.
to the square inch, and for every 3" from the point of
resistance A, the pressure will be increased 201b.
, Falcon.

Six,—In Illustrating geographical phenomena by the
globes, It l sometimes expedient to consider the earth
as stationary, and the stars and ebb as revolving
round it, but this it is to be understood is done for
the sake of illustration and no by no means
implies heresy, the party may belong to the orthodox
faith, although he makes this supposition. The object
in dealing with these questions is to illustrate, not to
philosophise, and although astronomers have demon-
strated that the sun is the centre of our solar system, and
that the stars have a proper motion of their own, it
will notât all militate against their conclusions, when
for the sake of illustration we make assertions which
seem to contradict them. In the following remarks
we shall consider the pole star as immovable, and
we shall move the globe in any dlrectlou as may best
answer our purpose. If Archimedes was unable to
move the world, for want of a place on which to fix;
his machine, we can at least move our miniature globe
to suit our convenience. The sphere may be repre-
sented under three aspects. (1) the right sphere (z)
the parallel sphere, (3) the oblique sphere; and we
shall show the appearance of the sun and stars to.
those who Live In each of them. These aspects of the
sphere have particular reference to the pole star and
the equator. Where the equator makes right angles
with the horizon, as in Fig. 1, there we have a right
sphere, and iu whatever sign of the Zodiac the sun is

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