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use. The two parts when brought together present a rounded form, the exterior being fluted like a washboard, and the interior being made concave as shown so that buttons, hooks, Ac, may be clasped without damage
1 hu upper part of that portion of the device which clasps the clothes, slides in grooves made in the side pieces of the frame, and is raised or opened by pressing back the bolt which locks it to its place, and pulling it upward by a knob or handle provided for that purpose.
The clothes are fastened In by pushing tne knob down. Common tubs and sine washboards are used ■ the washboard is temporarily fastened in the tub, upon which the clothes are alternately drawn, and pressed
Sir,—Several suggestions have oí late been made in the English Mechanic for blowing organs. Perhaps the method by weights proposed in the '• Manuel du Facteur d'Orgues " may interest some of your readers. Of this I forward photographs of the plates for your use. In the text it is merely said that Ihe drawings sufficiently explain the plan. The scale is the metre, and is in tenths—one metre = 39-371n.; one-tenth = 3 93. From this scale I find the crank = about 4ln.;
boxhead come into use and easily carry the box round tho curve, or allow it to be easily stopped for tilling, and again started by hand, when the rope catches it and it proceeds in usual course.
The Ingenuity of the inventor ha», perhaps, been taxed as tcverely at the curves as anywhere. Curves up to 15 deg. are managed by simply inclining the carrying wheels at a slight angle (Fig. 8), and using them in u series. Sharper curves up to a right angle are managed as in Fig. 0, where it will bo observed tte box leaves the rope on entering the curve, is thrown^ upon the wheels of the boxhead for support ; these wheels catch the little iron railway shown at the outer edge of the curve, which railway is entered at a, descending gradient by the momentum of the box cm entering It. It runs down the descending gradient by the force of gravity, and is then caught at its emergence from the curve railway by the rope, thence progressing in the usual way. The terminus (Fig. 7) la practically a repetition of the arrangements at tho driving station, so far as the rope and box arrangements go. The rope here necessarily descends to the terminal drum, and .the box is caught by the little Iron railway, as at the sharp curves and the starting point, is carried on the wheels of the boxhead, and Is stopped by the attendant to be tilted, when it is again manually run on by a slight push, so as again to catch the rope and commence its return journey. The terminal drum ia fixed on a short length of tramroad, and as the rope needs tightening, or the reverse, Le hauled up or Blackened by a chain run through a couple of pulleys aud anchored firmly some short distance beyond. The proper tension of the rope If, thus maintained by the most ready and simple means, Even in case of the breakage of the ropo it is found practically not more than a couple of spans of the ropo actually
down against tho bottom of the tub; and they may be rubbed when required by applying one hand to tho middle cross piece. This invention enables thcoperator to use suds hotter than the hand can bear, which dissolve the grease and dirt much more rapidly than suds at a lower temperature. J. в. T.
Sir,—As Improvement and progress seem to be the watchwords of our paper, would you allow me to make a suggestion with regard to the index, viz., that it should extend to the " Notes and Queries " column. 1 am sure n large number of brother subscribers would agree with me iu saying that it contains more valuable practical inlormatlon than all the rest of the journal. I am aware that it would entail a good deal of trouble and expense to get up an index, but would suggest that it shoald be got up as an extra, and paid for accordingly and. for my part, I should be perfectly willing to glvehalf-a-crown or more for it. If you think the above worthy ol publication, perhaps some other subscribers would give their opinions ou it.
J. Brown, Bedford-street, Belfast.
[Such an index would not cost halí-a-сго'лп, or more than twopence.]
feeder of bellows, about Hin. wide and 8in. deep; bel-
I am net able to say how the machine will answer
TUE WIRE TRAMWAY AT BRIGHTON.
(For illustration, see next paye.)
Sir,—The wire tramway system seeaistobe gaining
filant was designed. There are 112 posts in tho whole
MEAN DISTANCE OF THE SUN.
Sir,—By the application of Kepler s third law. Rs to Ihe square of the periodical times being proportional to the cube of the mean distance of the sun, and in deducing by that law the mean distance of Venus from the Sun at 07,301,800 miles, that of the Sun being 93,044,100 miles, and the distance of Venus from the centre of the earth being the difference between these two distances, or 25,742,300 miles, the mean horizontal parallax of Venue being 31"-6B854, which equals 31)50 Oft miles, divided by 25742300 miles.
Now, the mean distance of the Sun is to the mean distance of Venus from the earth, so is the mean horizontal parallax of Venus to the mean horizontal parallax of the Sun—viz., U3O44100 miles: 20742300 miles :: 31" 69854: 8" 77 very nearly.
By Logarithms-7 UG8Ce90: 7410C4860 : : 1 50103*34: 0-94291WO = 8"'7099е8. VERITAS.
SCALE ON STEAM BOILERS.
Sib,—Hating charge of я number of steam boiler«. I feel nnxious for some Information on the following important results ithe boilers used are single-flued Corntab boilers) :«—For a lengthened period of time we have used cold water feed. The result has been, In those parte of the boilers least accessible to hand labour beitijç for cleaning, a gradual formatiou and increase of thick, bard, stony scale on the boiler platee. In order to Increase the steamtng capacity of the boilers, the owners adopted ■* Barton's patent aelí-acting feed wiiter heater," changing the feed water to a temperature of 212«. I may hero mention that the feed water 1* heated by the exhaust steam. Since the change to hot water feed, the Scale has fallen away from the boiler plates, relieving itself in large flakes, leaving the boilers quite free from incrustation or scale of any kind. I am quite at a loss to understand how this occurs, and am very anxious for information as to cause and effect, as resulting under my own particular notice. I would deem it a great favour to have the opinion of any one ot your correa pon dent я on what Ï consider a very Important subject lu reference to future management of steam boilers. S. C., Birkenhead.
THE "ENGLISH" VELOCIPEDE.
Sir,—I perçoive there are ono or two of your correspondents that seem puzzled as to the way in which the " English" velocipede is guided, I believe this may in some measure be owing to the printer's mistake in my letter, where the fourth property of thiemachme is described. As it stands it reads, "the driving wheels not slipping.*' It should be, "the driving wheel not slipping.
In answer to "C. T. W," p. 142, No. 2583, the machine is not guided by the hind wheel, but it is driven by the hind wheel exclusively. The guiding wheels are the front ones, on each side of the driver.
In answer to "Garibaldi," p. 100, No. 3735, there is a connecting rod from the guiding wheel axle to the guidiug lever. It is jointed at each end. The fulcrum of the guiding levers muy be above or below the connecting rod. 1 have preferred it below. The cranks are set at the quarter circle. I would recommend four alterations:—Slake the crank lin. longer, place the lever bar lin. further from the seat, raise the scat 2in., and bend the hand lever about 3In. townrdx the seat.
DARK LINES IN SOLAR SPECTRUM.
Sir,—Permit me to assure Mr. Proctor of my firm belief in the earnestness and honesty of our physicists; it is not there they fail; but I believe very obvious considerations are being constantly overlooked, simply because of their familiarity. What is more commonly observed than the gradual fading of the light of the sky after sunset; but can Mr. Proctor affirm that the received explanation of its cause in supported by u tolltary observed fact? Yet Kirchhoff, patient, cautious, and clear-sighted though he was, seemed completely blind to the unsatisfactory character of the evidence sustaining it; for If he had only suspected this was somethiug more than simply reflected solar light, he would readily have understood how our atmosphere could contain such a widely diffused element as Iron In sufficient quautlty to ьсогс the solar spectrum with dark lines through the light generated by its chemical combination with oxygen. i ho same remark applies to calcium, magnesium, sodium, hydrogen, carbon, and other elements, whose chemical combinations with oxygen are known to evolve light, and which are also constituents of the surface matter of the globe. For I hold it to be a demonetrablo truth that the earth Is continually receiving matter from space, which, chemically combining under solar action, generates the diffused light of the sky. The geologist gires valuable testimony upon this point. With reference to the Editorial remarks on p. 1*3,1 have farther to observe that the ordinary employment of a photographer is nothing less than a series of very delicate investigations concerning the nature and properties of light. I enclose my card to satisfy our worthy Editor regarding the profession of his gueesing correspondent.
Sir,—In answer to "F.R.G.S.V Invitation, I will lay my case and wants before him. I rm a clerk in a cotton mill, 20 years of age, and receiving 12s. a week, and it I get 20s. a week by the time 1 am 23 years old I may think myself lucky. There is little prospect of getting a better situation, as there are far too many clerks already, and the profite of cotton manufacturers are so small. In consequence of the keen competition which exists at present, that they are unable to pay fair wages. Well, I think It folly to stay in Knghind at my present situation, any longer than I can possibly help, and so I have come to the conclusion that it is not only wise, but necessary, to emigrate, though doing so will be about as painful as cutting off a limb, for 1 am a Sunday-school teacher, and a memberof a Christian church, and have kind parents and good friends. After some consideration, 1 have decided to turn farmer when I emigrate, as that trade appears to be the best and most lasting; and during the next three years, while saving up enough to enable me to emigrate, I shall do my best to acquire some knowledge of farming. What I wish "F.R.G.S." to do, is this, to inform mc in what part of Cauada or Australia, are lands to he had free, or at least for a nominal price, what eort of lands they are, and how to reach them.
I must say that I have n decided preference for Canada at present, though quite open to conviction, should "F.R.G.S." think otherwise. I hope that "F.R.G.S." will also mention which is the most suitable climate, nor should I wish him to confine his information to Canada or Australia, but hope that he will give ue the benefit of his wide, accurate knowledge, of other parts of the world, and the means of reaching them, where any working man might, lu a few years, by pluck, energy, and solf-deuial,have a comfortable farm, or other occupation, and be able to
briDg up a family comfortably. I will conclude by stating that I believe my case is but one of thousands; indeed, several of my personal friends are'ln the same position, which I can assure you we should be glad to mend. Cotton Cleiik.
RENOVATING OLD FILES.
Sir,—I notice an article in your last publication on renovating old files bv the use of the battery. I here« with give you a simpler and cheaper method, which I have used for a long time, and found to be a great saving in the mechanics' shop. Clean the files with a hand brush and a concentrated solution of soda or caustic lye, placing them m a dish or water-tight wooden box containing water, adding to the latter one-eighth part concentrated nitric acid, and mixing well by agitation, then leaving them at rest for flvennd-twenty minutes; next, withdrawing them, and washing them with water and a brush, replacing them In the dilute acid, to which is added a second eighth of nitric acid, and letting them lie for fifty minutes, then again washing and brushing, and roplaci ng in the bath, to v. hich ¡is added cone-sixteenth of sulphuric acid, finally, washing in pure water and milk of lime, to remove all traces of acid, and drying. A smart boy could renovate two dozen of. large files in two and a half hours!
In my communication about making fishing rods, I made an error in stating the weight of the salmon rod, It should have been 27oz. Vivía Sî'erahdum.
subject, but must confess my inability to understand why such Is the fact. With all due deference to his opinion, it Is stated that some of our most successful spinners in the country work them; und if it be not asking too much, will Mr. Slater kindly give us hie reasons for condemning them, as it Is a point which 1 am sure tho spinners of the district would be glad to have explained.
Scutcher Drauylt/.—My experience goes to prove that a down draught Is as good as an up one, aud an up one equally so to a down one. I prefer a down draught, as the quantity of dust tius required at ■ large couceru not only make a room look ugly, but arc often in the way. Mutual Improvement,
Sir.—Draughts.—In my last letter to the lads, to whom this is also addressed, I endeavoured to show them why tho draught should not be called "simply the difference between two surface speeds." And now
Sin,—" Harmonious Cotton Spiuncr" has not penetrated тету deeply into the mysteries of cotton spinning if he has not yet discovered a draught between the ieed roller and lap roller of a carding engine. He says there is not, nor ought there to be a draught here, and nsks " of what use a draught would be?"
That there is a draught the letter of E. Slater, Burnley, ou the same page as his own, 183, will perhaps convluee him ; as to its use, I may tell him that it is to keep the lap stretched between tho two rollers to prevent its bagging, which It otherwise would do, causing irregularity In the feed. Ills other assertion about there being nodraught, buta "contraction" between dofferand delivery roller, is rather Inconsistent with n statement made by him to "Factory Lad " on draughts in the same letter, in which he »peaks of a draught of Мб and 2 in the draw-box of engine, which, of course, is between doffer and delivery rollers.
E. Halmshaw, Gomersal, is wrong in stating fp. 183) that I said " It is immaterial whether the babbln leads the flyer, or the flyer leads the bobbin" in the roving frame. I offered no opinion on the two methods, as there was none called for. I merely attempted to describe tho working of the cone, sun and planet wheels, and reversing motion, which was all that was ;'■■!.' i for by the correspondent who requested an explanation of these parts, and I said It was immaterial to tho description which of tho two methods was taken to illustrate the matter, as the mechanism was alike In both cases, the ouly difference being in the arrangement of the gearing; so that when the bobbin led the flyer, the wheel I) (p. lili) would revolve In the fame direction as the wheel b, and in a contrary direction when the flyer led the bobbin (for "wheel a," in the sentence *' which in this ease revolves in the same direction as the wheel a," road " wheel ft").
I am not «ware that there is any superiority in the make of the thread when the bobbin leads tho flyer. The roving is more compressed, consequently a greater length and weight can be laid on tho bobbin, There is • waste made, as the roving is воt thrown off from the bobbin when the end is broken, as Is sometimes the case when the flyer leads the bobbin; but these advantages яге more than counterbalanced by the extra power required to drive, and the extra wear and tear of machinery. 1Î. W. K.
Sin,—Draught of Carding Engine,—Our new correspondent, "Harmonious Cotton Spinner," seems to understand his business. He is perfectly right hi stating that there is not, or ought not to be, any draught between the lap and feed rollers; it would not only be of no u«e, but would cause irregular feeding in proportion to the draught or pulling out of the lap.
Tho callender or delivery rollers should be so arranged as to take up from the doffer without being slack or very tight. II slack, the sliver probably enters the funnel lumpy; and if very tight, it would be Btretched unevenly. Let the rollers take up properly, and there will not be any material draught between the doffer and rollers. Tide decides the question of draught to be between feed rollers and callender rollers (not doffer).
Draught of Drawing Frame.—There are four replies to this question, Including- one from myself, page 162. The one from " IÏ. W. R." I think is rather too keen in the preparing draughts. With regard to Mr. Slater, of Burnley, there must bo some mistake, judging from his two lengthy communications. I must give him credit for knowing better than equalising the three draughts. Surely he is not in earnest lu advising people less Informed than himself to set rollers Uh he is represented to have stated.
1 cannot now drop on tho question of E. Haberghain respecting weights, but tho following may prove serviceable to many readers: —
Avoirdupois.—27 11-32 grains = 1 drachm; 10 drachms = loz., or 4:i7¿gr.; Ь'юг. = Hb., or rOOOgr.
Troy.—24grains = ldwt; 20dwt = loz.,or480gr.; 12oz. = llb.,or5760gr.
For cotton-spinning purposes a combination of these two tables Is used: thus, 24rr. = ldwt.i lS'&idwt (say 18dwt. QSgr.) = loz., or 4Ü7tgr.; ltkjz. = lib., orTOOOgr.
I notice Mr, Slater's remark respecting drawbox rol lei* to a card being '* penny wise and pound foolish," and have given seme thought to the
as I cannot bear to see a rule put into a lad's head without the reason of it, I will try to make them understand the rules that are given in books "for finding speeds and draughts." if a lad Icrows a rule I admit he can work by rule, but if he knows the reason of it as well he can make the rule work also; and circumstances often occur that render such knowledge necessary. A principle thoroughly understood is easily applied. To the subject, then. I told you in my last that the expression "a given time," which occurs so often in subjects of this kind, means nothing more than the length of time you fix upon during which a thing may act, so that you may know what it will do In a long lime from what It does in a short one. I remember the expression, simple as it may seem to me now, bothered me a grea»: deal when I was a lad. I dare say, from the example I gave you In my last, you would Infer that the travelling speed of any point or mark you might make upon the diameter of a wheel would depend upon Us distance from tho centre of tho wheel or the point around which It revolves. If so, you were right ; the travelling speed increases in proportion to the distance from the centre, and it is to i in/ advantage that is taken of this plain truth that we owe all the various speeds of revolution that we have in the cotton mi 11, from that which gives to the "fans" and " scutchiug beaters" their terrific roar, and to the " mule " or " throstle " spindles their whirling buzz, to that of the slowly creeping "worm wheel." You will observe, too, that the terms "driving wheel," "driving strap," Ac., are very suggestive. A thing that is driven must be occupying Bome space or position coutiuually that auothcr Is as continually taking from It by pushing it forward out of Its way, во that from this circumstance you may properly infer that both "drivingstraps"aud "driving wheels" communicate their motion upon the samo principle. I do not mean that you must call power the principle, but that the power in the two cases operates, not upon two distinct and separate principles, but upon an identical one only in a modified manner. If you will, I call the hindmost pushing the foremost the principle. It may also have occurred to you that the diameter of a wheel and the number of its teeth correspond to each other. So they do; not that every wheel of rtiu. diameter will be found to have the вате number of teeth, because there are different " pitches" of teeth, but in all calculations of speeds or draughts you may either take the diameters of wheels or the , numbers of teeth and they will answer as one. As an instance—a pulley Gin. diameter drives by means of a strap another one 2ft 6In. diameter ; how much of tener in a given time will the driver revolve than the driven? You know Oin. = ¿ft, and 2ft Oin. = 5 halves, so that it must be 5 timos oftener. but if the two were wheels, tho driver having 12 teeth and the driven GO, then we could divide 00 by the 12, and the
00 quotient would be the same as — = 5. Or if, instead
12 of calling the driven pulley 2ft. r»ln„ we had called it 30in., we might have divided the 30 by 5 with the same
30 result, as — =. 5. This little example, if you think
в for yourselves, will enable you to see that you may measure Wheals or pulleys by any standard you find
most convenient, as feet, inches, Un., ¿In., —in., just
10 as you cau deal with £ s. d. You can reduce £1 to 20 Bhllllnge, or 240 pence, or 480 halfpennies, etc., so you
92 may reduce lft. to 12in., M eighths, or —in. Another
16 б Instance. You have two rollers, one—In. diameter, the
other ljin., thou you would call the first 0 and the last
t> 14, because —iu. bear tho same proportion to ljin.
14 that 6 does to 14, or — = l|iu. There is another
8 tiling that I am sure must have occurred to you: it is this, that in a ect of rollers it is often the oase that both the diameters of tho rollers themselves, as well as the diameters of the wheels by which they are geared together, are taken advantage of to produce tho draught. If you have thought upou tho subject oven but so far as to sec this fact, you may easily master It entirely; so with a few more examples I will leave the subject with yeu; I know you will fight It best in your own way. Look at the sketch Fig. 1 :—There aro
ibivc driver« and three driven. Tbe first driver is 181n. <*isxiNot«ir, the tiret driven is loin, diameter. Now, ♦opposing the first driver to make 50 revolutions per minute—you will perhaps know that " per "is a prefix, &ad »ignifies'lbrougb. by, or in—tlicn how many revolotloob will the first driven make in that time? You
is x 50
can put it this war, 10 : 18: :50, and =
10 •Xi» You see it lain proportion to their diameter,because &o besirs the name proportion to 90 that 10 doce to 18,
18 90 ' 90 140
шл '— *re oí the same value as — — — = — or
10 50 60 50
4, IB В 4
1— and — = 1-, or 1—. If now you were asked to
5 i' 10 5
Ctvvp a "rule" by which the speed of the driven could be found from that of the driver, you would say,
■m^ift^Jtt ike speed of ttu' driver hy its diameter, and divide the prùiwct by the diameter of the' Arisen. But just think for a raomcut how silly the rule sounds—multiply the rpeetl by tbe diameter! It would be just as easy to multiply я pound of cheese by a cartload of turnips. I hiivQ no doubt but that you have sense enough to sec that numbers alone are ail we can multiply, or'multiply by. 1 have not forgot being bothered with this eUly" tiling myself, and the worst of it was I bad no >1fciiasic Ю help me. However, when we say the diameter Is 18in. and the speed ft* revolutions, the.IS Is tbe value of the diameter and tbe 50 the value of the speed, so that we convert both Into the numbers which represent to us their vnlue, and then we can either multiply or divide them. Now to the next pair, driver and driven. We find that the 2nd driver roast make DO revolutions, being fixed to shaft of the l-i driven, then it feeing SOin. diameter, and the one it drive« 8in. diameter, how many revolutions must the latter make? Here, again, 8 : 30 : : 90. And 90 x SO 225 20 225 20
= 2S5, and — = —, as — = 2J, and —
8 90 8 90 8
= 2$. So the 2nd driven makes 225 revolutions. Now, then, to find the speed of the last. We have 225 revolutions and lCiu. diameter driving 6in. diameter, and
235 x 18
a^ain, 6: 16: : 225 Is to the sum required, and =
6 600 ID Л0О 16
600, = -,or— = 2», and — = Ц. We have
225 6 225 0
now found the speed of the last drives pulley to bo 600 révolutions to SO of the first driver, 12 to 1, what then would be tho draught between them? The 1st driver is 18in. diameter = 5Л 52io. circumference, and this x 50, the number of revolutions = 282 6in., the distance it would travel. The last driven is Oin. diameter = l*84io. circumference, and this sum x 600 — HS04in. Now К we divide the two sums, we must, as we already know, obtain the draught there
11304 s between tbe two speeds of travelling, aad
= 4. With 12 times the speed of revolution only 4 of a draught? 'How is this? Look at the sketch again and you will remember that the diameter of the let driver is 18in., or 3 times greater than that of the last driven, so that if you multiply tho draught 4 by я it becomes 12, or in proportion to tho two speeds. You
will see this more distinctly if you observe that tho surface speed of both 1st driver and 1st driven is the same, both being connected by tbe strap. The same is the fact also with the 2nd and 3rd pairs. But observe that tbe 2nd strap must move twice as quickly as the let one, because it receives its motion from a diameter twice as great as the let is driving. The same differсйсе likewise exists between tbe 2nd and 3rd straps, to thai from the motions of these alone you have obviously tbe draught. The 2nd moving twice as fast nth« Ht causee a draught of 2, aud the 3rd moving twice as fast as the 2nd, causea a further draught of 2, No that we have 2 let draught x 2 the 2nd draught, Md2 «2 = 4. From what has been already said I think you will readily apprehend that if we had converted tbe value* of all the drivera into one term by multiplying them together, and called the product the value ol the drivers, and done in the same way with all the value« of the driven, we should have made the whole process much shorter. As, value of all the drivers IK x 20 x Ы = 5760, and value ot all the driven б x 8 x 10 = 480, and
Therefore 48) bears
proportion to 5760 that 50 bears to 0 Ю. Hut If we apply tbe principle to getting at the draughts of differeot Une* of rollers In и "set," the former course Ы the beet. Look now at sketch, Fig. 2. Here you see two drivers, the first called the "frout roller wheel,4 its value is 16, the second called "change wheel," its value is 20; also two driven wheels, the "carrier," value 40, and "back roller wheel," value CO. The diameter of " back roller" is ito., its value then is 7, the diameter of "front
object of tills example is to show you that it is not necessary that we should know the speed of revolution in order to find tlio draught that any arrangement of wheels nnd diameters would cause, because we are certain of finding the draught if wc divide tho value of the driven by that of the driver, the ratio between thcin being the same whatever be their speed of revolution. What is the draught, then, that such an arrangement as this sketch illustrate» would cause? Let us see first what is tho ratio between driver and driven ; then, lfi x 20 = :t20, value of driver, and CO x 40 = 2400, vnlue of driven ; then, 320 : 2400 : : l to 24"0
the number wo seek, and = 7*5, or 7£. You
320 must observe that this is only the ratio between the values of the wheels, drivers and driven, no account having been taken of the diameters of the rollere "back" and "front." The diameters have been left out so far in the calculation that you might see clearly to which terra or sum their respective values belong, And I think you will be ablo to discern that the surfact*of*the frout roller must be looked upon as a driven surface, and that of the back as a driving one. If their diameters had been equal, then, of course they could have been left Oul altogether, but the "front"
8 diameter haying a value of 8, or —, and the back of 7,
8 or Ï, obviously we must bring them in, and asthey affect the amount of the draught in the same proportion as they affect tbe values of driver and driven, we can either multiply the sum of the draught by the value of the "trout,* or driven roller, and divide the product by that of "back *' one. or driver, as draught from value of wheels 7 5 x 8 value of front roller -j- 7 value of
4 back roller = 8—, or we can bring them in alto*
gethcr as the value of driver and driven. Thus, the value of driver is Iti x 20 x 7 = 2240, aud value of
driven is 40 x CO x 8 = 19200, and = 8 ,
4 or 8—. I hopo now that you will fight your way
through tho subject. Never mind how the wheels are made -to twist and turn, nor how many of them there may be, tbe principle that holds good with 5 holds good with 50, und you may understand it if vou will. My object in writing is. to ret you thinking. Vou will see at the end of my last letter I told "Factory Lad" to divide a total draught of 7, obtained from 4 linos of rollers, by 3, and make his draughts equal, aa 2¿ + 2i + 2¿ = 7. 1 purposely in this caso left my meaning obscure, because no person ought to act upon a short isolated answer from any correspondent, especially when, as in this case, the subject is a very important one; if he does, he has no right to complain, when, too late, he finds it out that both he and his fellowcorrespondont have misunderstood each other. My meaning was (from front to back) between frout and 2nd roller, 2 5; between 2nd and 2rd, 100; between 3rd and 4th, 1 67; от, reversing their order, 167 x 169 x 2'5 = 7,0557в, or something aw near this order as he should find convenient. I was ence rarely puzzled by a similar auswer given to me bv a very intelligent old man; however, I learnt something from it, and if you think, yoj. will do the same. E. S., Burnley.
P. S.—If no one else answers " Oldham," 2861, I will do so, though I do not like to recommend books, &a I would rather sec information given through the pages of our Mechanic ; besides, books seldom answer tho particular question a person may wish to ask. You will generally uudauything in them but just the ono thing you are fast with, aud that which is worth putting in a (¡cod book is worth the нрасс it will take up in our Mechanic, for the sake of those who cannot come at the good book.
Sir,—I am greatly obliged for the numerous answers to my question respectiug the proper method of arranging the draughts in a drawing frame. I find that "Mutual Improvement" comes the nearest to what I have practically found to be the best arrangement, as I have my draughts at present 341 x 1*75 x 117 = 700 working "fair Dhollera.4 I am rather surprised at the figures given by E. Slater, for if 1 put 2£ draught between each line, the total draught would be 12*64, because 2-33 x 233 x 2-33 = 1264; the error appears to ha70 been made, by adding instead of multiplying together the separate draughts. With respect to" B. W\ It.'s"remark on scutchers, 1 prefer the down draught machines, as they do their work better, and are not so clumsy in appearance. I have both sorts working, but am decidedly in favour of tbe down draught machines. Factory Lad.
SEWING MACH1XES.-REPLY TO "STUDY."
Sir,—I am thankful for the good Intention of "Study " to point out one or two slight errors in my letter at page 15S, but tho errors, such as they are, only ainouut to a difference of opinion. I must acknow
7 ledge myself wrong if a —in. shuttle trilù mois m qood
16 a stitch on boot-work at « stnaller ом. Finding the majority of workers on boot-work do not approve a 7
—in. shuttle in a No. 2 Thomas, a smaller size was 16
taken fairly for comparison. If "Study" has compared things uulike, his conclusion may be wrong, and my 6 tat emeu t that Singer's shuttle holds most, Howe's next, and Thomas's least, is not a slight error.
I quite agree with ** Study " that Thomas's cam is defective. By the way, if through the English Mechanic the makers aud blind imitators could have bceu convinced of tins years ago, boot makers, tailors, Ac, would have experienced much less trouble in their work. The question of tbe pause, and other matters, will be considered in due cause. Having laid down a plaufor the treatment of the subject, iucluding descriptions of a variety of machines, and comparing them fairly, so as to be in te resting to the genei al reader, I
wish to adhere to it. When the subject is sufficiently advanced, such remarks as " Study *' has kindly offered, will be better appreciated, and will then bo thankfully received and replied to by the permission of the Editor of the English Меспамс by
A Practical Ma».
(Continued from page 114.)
Sir,—It ie difficult to conceive oí any method of making a lock stitch not already tried. The shuttle to pass ihrongh the needle loop, the hook to carry the uetdlo thread around the lower thread contained in a spool, tho form and working of euch hooks, spools, and spool holders, and their influence in determining the character of tho stitch, deserve here special attention. Hereafter it will be expedient to give a description of some of the machines Invented since 1846. Ol theso some display great ingenuity, true mechanical principles, and simplicity of construction;others, the simplicity of tho inventors. Many of the unsuccessful have boenruined in mind,bJdy,and estate. While theso
may receive our sympathy and the successful our praise, all should consider how insignificant ie the work of the beet compared with the accumulated labour of all. Fiom the weavers' shuttle in the time of Job, to the English lace machine, with Its many shuttles and eye-pointed needles (from which Howe may, or may not, have got his idea) and to the latest or best production, we trace a gradual improvement —a Darwinian development. The best examples will be selected, aud predominate from their fitness and beauty ; the inferior will die out. It is well known to tho trade that some varieties have already died out, while others have advanced. In no particular did the Exhibitionsof 1851 aud 1862 display agreatercontrast than in the matter of the sewing machine. In 1851 it was scarcely known, and the one In the Exhibition appeared a mere novelty. In a few years they were in general use, and were among the most interesting displays In the Exhibition of 1862. Machines making tbe lock stitch, tbe two-threaded chain stitch, and the siugle thread chain stitch, were all at work. Anxious inventors vied with each other to please the public, whose judgment was decidedly In favour of twothreaded machines, especially the lock stitch. Since . then, untiring effort* have been put forward to advance the ealc of single thread chain stitch machines; It has been named the best stitch with unwarrantable boldness; with surprising impudence its superiority has been asserted over lock-stitch machines. A proof to the contrary is shown by an official return of the American sewing machine makers. The actual business done in the year ending June, 1867, was, for the chain stitch, by Willcox and Gibbs, 14,152; for the lock stitch, by five makers, 106.КУ8. Thus seven and a half times more lock stitch than chain stitch machines were sold according to the American official return, and if proper returns were made for Great Britain there can be no doubt that for every single chain-stitch machine sold there would be twenty lock stitch sold. The chain stitch is easy to learn, and has such merit as to entitle it to notice, but twenty reasons to one claim for the lock stiteh the preference.
In the development of the lock stitch sowing machine, one of the earliest attempts to improve it wae to substitute a carrying fora eliding motion of the shuttle. The shuttle was placed ou a horizontal working disc and revolved with it, tho rounded part being supported on the disc, the lace of tho shuttle being curved to correspond to the perpendicular face of the frame against which it worked. In another machine tho disc revolved vertically, the shuttle face being flat, and worked against, a perpendicular ring surface. This circular motion of the shuttle had two serious defects—first, it must either twist or untwist the shuttle thread; and, secondly, it nearly doubled the travel of the shuttle, whereby a grinding tendency was produced, so that the shuttle would oftener waut repairing or renewing. This arrangement was a step made towards a machine displaying the very highest class of design and practical ability, known as the Wheeler and Wilson machine. This revolving shuttle arrangement has been followed by other modifications. The shuttle has been made to travel in a nearly circular form. In a recently invented machine, but with an important improvement to prevent tbe twisting or untwisting of the thread, by causing the shuttle to be carried around without somersaulting, by placing it on a shuttle frame worked from a supporting cuido by a crank motion. The rounded part of tho shuttle is supported on this shuttle frame, the shuttle face being thus keptagalust the perpendicular face of the machine. Instead of the shuttle reciprocttng. with tbe least waste of movement, this plan makes it travel over a largely extended surface, which is a mechanical defect iu itself, and has no advantage in working the needle thrend. If a motion could be contrived for passing the lower thread through the needle thread loop without touching it, it would be perfection. Tho Howe system is the nearest to it, and the plan last described the most remote from It. An ascendiug and descending motion of the shuttle serves no useful purpose, it wears the shuttle faster, strains the needle thread, and thu* limits the speed of the machine.
Other machines of recent production resemble an older patent which provides for the carry! ug the shuttlu ou the top end of a vibrating lever. This arrangement imparts a curved motion to the ehuttle vertically ; it rises and fall« less than in the case last noticed, and is consequently to be preferred, the defects being so much reduced. An example of this class may be seen in the Little Wanzer band sewing machine. All the machines under the class here referred to have failed to come into manufacturing or trade nee—it would not pay for rich or poor to use them in trade.
It may be taken as a rule that n shuttle should trfivel horizontally, and no more than the actual distance required for the funnation of the stitch; travelling beyond it wears out the shuttle faster, as may be observed in the Singer class of machines driving the shuttle by a crank motion or its equivalent, instead of a cam. The cam movement has a special advantage over any other known plan for driving the shuttle, although In many cam machines it is not made available. "When the shuttle has passed the needle loop, the shuttle carrier should recede a distance sufficient for the needle thread to pass between the shuttle and carrier without touching the carrier. Many cam machines work on this plan, and it is a decided improvement Other minute defects or improvements will come under notice when a machinéis illustrated completely. The present plan of collection, classification, and comparison of instruments for the formation of the stitch is chosen as the best method to convey the information desired.
A more correct motion for working the shuttle than the class of circular moving shuttles, will now be considered. The shuttle slides with a movement reciprocating, as in the Howe machine, horizontally, but in a curved instead of a straight direction. The advantage here gained is reduction of the wearing joints and parts for driving the shuttle. The вате system has been successfully applied to work a shuttle in the end of an arm machine; the arm being specially arranged for stitching side springe into old boots, or any work that can only be stitched on the extreme end of the arm. The arm is so narrow as to admit the boot over it, with freedom to turn ¡the work in all directions. A circular recess is formed in the end of the arm, and in it works the shuttle horizontally; on the axis of the shuttle driver is fixed a pinion, which is actuated by a rack working lengthways In the arm from a cam on the main shaft, similar to Thomas's machine. Fig. 1 represents a plan view of the end of the arm containing the shuttle. The shuttle A is shown ready to enier the loop of the Deedle thread. U is the slot in which the needle rests while the shuttle is passing through the loop. To complete the stitch the shuttle travels as far as represented by the dotted lines, and then back again for the next stitch. For the purpose intended abetter arrangement cannot be conceived, but lor general work it Is defective as regards wear, owing to the circular surface С being so small. The part aronud which the shuttle travels soon wears, and then the curved face of the shuttle is not kept to frame, whereby the shuttle falls backward from the needle, and , slips or misses stltcn. It also requires too long a needle thread loop to pass around its bedy, the defect of which has been already explained.
It may be interesting now to notice how few of thosei/n^roi-<•./(/,) shuttlesand drivers have come Into use; yet they afford a rich store of experieuee for experimentors. Passing from the circular movement shuttle toabettercentrivance, ye! still workingon thesameidea of a direct circular movement, a wonderful success lias been achieved by the production of a machine substituting for the shuttle a metallic bobbin or spool to contain the lower thread, and carrying the needle thread around it by a rotating hook, as ia the Wheeler and Wilson Machine, or by an elliptic moving hook, forming the stitch in a somewhat similar manner i Ig. 2 represents a front view, and 3 a section of the metallic bobbin or spool. It is formed of two thin metallic discs a h fixed on a brass axis c, with a hole through it which fits qn the shaft of the machine to receive a rotary motion for winding on the thread, anil In the space between the double convex spool! It holds Щ yards in the Wheeler and Wilson, and in the,ElHptic spool HJ yards, of No. 24 cotton. Unlike the shuttle, there are neither holes norsprings to regulate the tension of the lower thread. The formation of the stitch in its pulling and straining on the needle thread is less perfect tlmu a shuttle stitch. The needle thread is sunk well in the upper surface of the fabric and pulled below too much, where it forms a ridge The two sides are not alike, but, while inferior to a good shuttle stitch, it la immensely superior to u chain stitch, either single or double thread, in appearance, strength, and economy of thread.
The spool is held to its work and rests between a spool-ring or holder aud the revolving hook which carries the needle thread around the spool. In due course the machine will be Illustrated, and no doubt will amply repay a careful study of its working.
A Practical Man.
NEEDHAMS PATENT " STARTER" FOR SEWING MACHINES. Sir,—A description of an American invention ■patented by Mr. O. H. Necdham, of New York which bas for its object the removal of a difficulty well known to workers of sewing machines, may be of interest. Although It is claimed by some machine operators that they know by the pitch or inclination of the treadle whether its movement should be up or down in setting the machine in motion, the difficulty of so doing is evident on reflection that there are tour positions of the crank near the upper nud lower dead centres, in which tho pitch of the treadle ¡e the same, but requires different motions of the foot to produce the movement of the shaft In the requisite direction Consequently, after stopping, the operator, not seeing the crank, cannot be positive that it will turn the right way in start lug without using the hand, or In its stead some automatic device like that under consideration. Fig. 1 shows a sewing nmchine fitted with the appliance, and Figs. 2 and 3 exhibit, on an enlarged scale, the appliance itself, in different positions detached from the machine. A collar A Is secured upon the rock-shaft carrying the treadles, aud is furnished at one eud with an enlargement or disc. Upon the face of this last, next to the treadles, is
fitted a slotted slide B, capable of moving transversely to the rock-shaft, which, of course, passes through its slot. This slide B, furthermore, is furnished with a lateral arm «, which extends over the adjaceut one of the treadles, as will be seen by reference to Fig. 1, In such manner that the application of the foot upon such treadle will depress the slide ß, the purpose of which will presently appear. The upper
end of slide В Is connected by a rod С with a rockino disc or sleeve D, placed upon the crank-shaft above? and having pivoted to it a pawl b, arranged in appropriate relation with a ratchet-wheel F, securely attached to the crank-shaft. The sleeve D, just mentioned, Is formed with an upwardly projecting leverarm e, the upper extremity of which is connected with a spring/. The action of this spring is to draw the
lever-arm, and consequently the sleeve and pawl, backward with reference to the direction of the teeth on lhe ratchet-wheel F.
When the foot is applied to the treadle In starting ilic motion of the machine, it acts upon the arm a of the slide B, and depresses the latter, whereupon the rod С nctuntea the sleeve D, and moving the pawl * forward, the latter acts upon the ratchet-wheel secured
to the crankshnft as previously explained, and of course starts the rotation of the latter belore any movement has been communicated to the treadles or through them and the pitman to the crank. As swi as the crank-shaft has thus received an Initia] Impulse the treadles are worked to continue the motion in the ordinary way. The movement of the slide, moreover is sufficient not only to thus impart motion to thé crank-shaft, but also to bring the pawl b Into such position that by its own weight It will drop out of gear with the ratchet-wheel, to permit, without Interference, the rotation of the crank-shaft. When the machine is stopped and the foot raised from the readle the spring /draws back thearm of tbeVvl „J, ,bn,g ,the pswI ln «"'table relation with the ratchet-wheel to repeat its action thereon when the machine Is again started, the movement of the lever arm operating of course through the connecting parts lifting the elide B, to its original position.
COLOUR-BLINDNESS. Sir -Ав I perceive that the subject of colour blindness is one to which you have devoted considérai, e space, I wish to ask permission to describe mv own case which I think involves a peculiar form of ti? evil that has not been dwelt upob by "Omicron "In his interesting, and probably exhaustive, memoir Ihe peculiarity to which 1 allude ie a tendency in n V eye to see: re./ as black, not as any intermediale shade between black and white, but as a decided Ыаск! t is not a little singular that, notwithstanding the great difference there is usually admitted to be between black and red. It was not till 1 was more than twenty years of age that I discovered that I had never seen red as a distiuct impression, and considering the remarks that "Omicron" has made on congenital colour-blindness, I believe I never have, and never shall see it. Ihe way in which I discovered my defect was singular enough, and as it evidences my complete disability to distinguish red from black, I make bold to tell the little circumstance." though it may not be thought te he of sufficient value for the pages of vour magazine that are devoted to correspondents' letter« On one occasion I splashed some white material I believe white paiut, over a nearly new black vest, and as the effect was rather a disfigurement, I thought I would remedy it by covering the spots with black Ink I did so, and produced, to my eye a result that 1 thought infinitely superior to the speckled aspect it had before presented; but I noticed that my friends did not at all appreciate the improvement that I flattered myself I had effected, and one more Intimate than the rest explained to me that, in point of fact to end quickly an unimportant matter, I had employed red iuk-iiragine my disappointment. Since that time, 1 have made many unfortuuate and ridiculous mistakes, and my own impression Is, whatever ingenious theory may account for It, that the defect is Incurable, aud I have not much faith in the use of coloured glasses, or other ingenious apparatus, to cure, or at least to mitigate, the inconveniences of colourblindness. I may mention that I recognize other colours as a normal eye. I express my thanks to 'Omicron " for his entertaining memoir,
STEAM LIFE BOAT.
Sir,—Concerning the steam life ¡boat to which you refer, my sentiments on the subject are embodied lu the enclosed copy of a letter I had the pleasure to address to Mr. Luff on the 14th ult. I feel assured that nothing like a steam life boat has so far been invented ; most of the plans merely aim at putting an engine in one ol our life-boats, which is absolutely impracticable. Riciiahd Lewis, Royal National Lifeboat Institution, 14, John-street, Adelpbi.
Dear Sir,—I havo your note of the 12th Inst. It is most kind of you to take such a warm interest in the life-boat cause. I trust, however, that the English Mechanic «111 not, on any account, solicit contributions for a life-boat to be propelled by a screw. After mature consideration, I assure you we are of opinion that such a boat is impracticable in the present state of things, aud perhaps you will also be of the same opinion if you will kindly give your attention to (he following reasons, which, in my opinion, militate against the adoption of steam life-boats. 1st. That owing to tho large quantity of water which must break over life-boats in heavy surfs, amounting often to three or four tons, it would be very difficult to keep the fires from being put out, aud at the same timr provide sufficient ventilation. 2nd. That the motioD of boats, under such circumstances, is so great and violent they sometimes staudiug almost perpendicular, with either the bow or stern uppermost, that the propeller would work at great disadvantage, and the machinery be perhaps liable to disarrangement. .'Ird. That since the space occupied by the engine, ¿c, would make it impossible to use oars if the former should become disabled whilst afloat, the boat would be at the mercy of the sea, and her own destruction, nud tliut of the crew, might follow. 4th. That wherever such boats were placed, this institution would require to have a qualified engineer to keep the machinery In order and work it when afloat, with a salary sufficient to maintain him, since the fishermen1 aud other local boatmen who now, as coxswains, for a small salary devote only a trifling portion of their spare time to keep the boats in order and ready for service, would neither have tho time at disposal nor the skill to keep machinery in order and to work it when afloat. 5th. That some time would be lost in lighting the fires and getting up steam. 6th. That it would be difficult to apply tho self-righting property to such boats, and if they were to remain more than momentarily keel up. the Arcs would be put out, or they might Bet the boat on fire. 7th. That the cases of failure of the present life-boats are so rare that the committee of the institution have not felt called on to expend largo sume of money on experiments, which might not afterwards be atteuded with any beneficial results. 8th. That w-herever steam tugs are available, 1 think It probable that steam power can be moro