CUSTOMS CONSIDERED SUPERSTITIOUS ARE NOT ALWAYS SUCH. 203 PÄTTERN-DRAWING CATERPILLARS. A gentleman at Munich, named Hebenstreit, is said to have invented a process by which he makes a species of caterpillar spin a kind of wadding, which is of a fine white colour, and waterproof. He made a balloon of this stuff, and raised it, by means of a chafing dish with spirits of wine, in the large warehouse where he keeps his caterpillars at work. He makes them trace ciphers and figures in the wadding. He accomplishes this by moistening outlines of figures or letters with spirits of wine. The caterpillars avoid these tracings, and spin their web around them: thus any fine figure which has been drawn is represented in the stuff. A piece of wadding, seven feet square, perfectly pure, and as brilliant as taffeta, was made by about fifty caterpillars between the 5th and 26th of June. WIDTH OF THE NEW LONDON SIR,-It may be thought presumptuous in an humble individual to make any remark on the judgment of the gentlemen managing the affairs of the New London Bridge; but if there is any thing wrong, or that can be improved, and there be yet time to make it right, it surely matters not from whom the suggestion proceeds. Since this bridge has been so much spoken of, I have oftentimes ironically said, "Well, I hope we shall have a better passway than the present, otherwise we shall have the bridge down again." Now, from what I can make out from the plans which I have seen of this bridge, the footway will be but seven feet wide or thereabouts. I would ask if this is at all adequate to the increasing population that is likely to pass over it? In all probability, before this bridge is opened for passengers, there will be five or ten thousand additional persons who will have to pass over it daily. Look at the buildings now going on on the Your obedient servant, CUSTOMS CONSIDERED SUPERSTITIOUS ARE NOT ALWAYS SUCH. SIR, AS nothing whatever can take place in the system but what is natural, the minutest and most familiar transaction is an object of scientific inquiry. It may likewise be asserted, that not only many of the customs of antiquity, which we are pleased to call superstitious, have rationality connected with their origin; but, even in the sciences, more correct ideas may have hitherto been maintained than the present modes of philosophizing among the illuminati permit us to appreciate. Under this impression I always feel happy to light upon the most ancient opinions to be met with on philosophical subjects, and, as respects modern discoveries, I find no ideas so correct as those formed at the time of discovery. Second editions leave many valuable circumstances omitted; and opinion formed on opinion (not upon the minutia attendant on experiment, which are parts of the fact, and wherein the truth is best discoverable) is substituted, until, at length, established opinion, in too many instances, has no better foundation than that of being the hypothesis of some professional dictator. In no instance are these senti ments more manifestly true than the modern practice, in all introductory treatises, of taunting the ancients with their little knowledge in experimental philosophy, and their idle speculations after first principles. The fact however is, that notwithstanding the high value set on experimental proof, without some better knowledge of the acting power of nature than what modern philosophy hypothetically maintains, we may go on for ages experimenting, without forming any thing like a system to correspond with nature. It is general principles only, and not insulated cases, that can be said to agree with the system, wherein a few species of elementary matter, and unity of means of action, alone exist. But to the point-It is considered nothing less than the result of low, vulgar superstition, the custom of applying the hand of a mau, recently hung, to a wen. Whence the practice originated, or how it was performed, even tradition does not say; but that it might have been, in some degree, efficacious, and would be still, if scientifically pursued, I think is nothing unreasonable to conceive. A wen does not consist of such morbid matter as not to depend for its existence and growth on organization and on ciroulation, and when we reflect on the very great ingress or egress of the ethe real fluids of a human body, suddenly deprived of life, and the possibility of a wen, brought in contact with the body, being acted similarly on, so as to promote circulation or destroy organization, there appears evidently more reason than superstition in the practice; at the same time, any other animal, under similar circumstances in all respects, would answer equally well. Failure of effect may, probably, arise from want of opportunity to make the application the instant vitality is subverted, and also from want of knowing that the parts brought in contact should have been previously made humid, or have a piece of linen between, moistened with some fluid, similar to that which promotes galvanic circulation. Having been oftentimes edified by the "Mechanics' Magazine," I submit the above pro bono publico. T JOINTING STEAM-PIPES. SIR, Permit me, through the medium of the Mechanics' Magazine." to return my thanks to Mr. Way, and your Correspondent at Bow, for their answers to my inquiry respecting the best method of making the joints of steam-pipes, at the same time to make a few remarks on the plans proposed. With respect to Mr. Way's method of using Parker's cement for making the joints of waterpipes, it may answer the purpose very well; but that gentleman can have little idea of the power and effect of steam, if he thinks it would answer the same purpose for steampipes. I have no hesitation in saying, although I have not tried the experiment, that the joints would not stand good five minutes after the steam was turned into the pipes; for, as soon as the pipes become warm, they would expand, which would loosen the cement, and, of course, spoil the joint. The method adopted with the pipes I made the inquiry about, was the one proposed by your Bow Correspondent; for, previous to receiving his information, the iron cement was made as he has directed, with the addition of a little dried clay, pounded and sifted, and mixed with the other ingredients, which is considered to bind them together better. Between the ends of the pipes was put an iron ring, about 3-8ths of an inch thick, and of the same diameter as the pipes; the two ends were then screwed firmly together, and the space between the flanches caused by the ring was filled up with iron cement, and well rammed with a caulking IDEA OF A SELF-ACTING CARRIAGE. chisel and a hammer, as recommended by your Correspondent, This part of the process requires to be well done, otherwise the joint will not be sound. The ring serves the twofold purpose of preventing the cement running into the pipes, and keeping a sufficient space between the flanches to put the cement in. Upon trial they were all found to be good joints, and have continued so, and I think it will be found the best method of making the joints where permanency is required. Mr. Way, in a subsequent letter, says, "he should doubt your Bow Correspondent being a practical 205 man, if he were to judge by his Your obedient servant, Henley-on-Thames, 66. When the wheels of the carriage go round, these knobs are pressed upon the ground by the weight of the carriage, till they come level with the ring, 6, and thereby press the air from the bellows to the tubes, 888, which have a valve opening inwards, and into the air-box, A; whence the air forcing up the piston, B, drives round the wheel, D, by the crank, E. The wheel, D, is joined to a concentric wheel, F, by a chain, GG; and the wheels, D and F, may have small notches of iron to go into the links of the chain as it goes round. Piston B, in the act of flying up, will shut the 206 ANSWER TO THE SHIPOWNER. stop-cock communicating with the air box, and open it in going down; or ra ther, there should be two pistons and cranks acting alternately. *་་ * By filling the air-box with compressed air, by the force-pump, to give it the first impulse, the action of the bellows will keep good the supply. If steam were applied as a power to a carriage upon this principle, it would supersede the use of a cogged railway. I have seen a velocipede upon this plan, with but one large hind-wheel, and the small power-wheel, D, driven by the hands. There were two handles, one on each side; the one lying up, and the other down.. I am, Sir, yours, &c. Coldstream. J- M ANSWER TO THE SHIPOWNER. SIR,In reply to your letter of last Saturday, from "A Shipowner," allow me to offer him a word of Latin, quoted from an intelligent and most acute observer: "Mor reficit rates Quassas, indocilis-pati." HOR. Ode 1. "The impatient man mocks us about the repairs of his broken ships." to require "extensive repairs?” The time, at least, is well chosen; this proposal may pass on Midsummer-day; but I want to know at whose risk he will send his crazy hulls into the Baltic from September to May? Let him ask Captain Lyon, or any of that brave crew, at whose risk ill-appointed vessels may be sent into northern latitudes? "Never, perhaps, was witnessed a finer scene than on the deck of my little ship, when all hope of life had left us. Noble as the character of the British sailor is always al lowed to be in cases of danger, I did not believe it to be possible, that, amongst forty-one persons, not one repining word should have been uttered."—Lyon's Narrative. 66 And is it men of this class that our Shipowner" will make the instruments of a sordid resentment? The shipwrights, however, are "stubborn, misguided, and shortsighted," if they desire to partake, in some small degree, of that national prosperity now generally diffused, and to which their own labours have been greatly subser Let him ask Dr. Birkbeck if this vient. But some of these ingeni is not a fair translation? I wish Horace had gone on with this subject, for it is really painful to express the sentiments that rise out of a letter which appears so strongly tainted with malignity. The question does not touch my interest-I am a stationer. Does this man really rejoice, that it is in his power to revenge upon thousands of his poor labouring fellow-countrymen some imagined insolence?-by himself much, and more by his influence, to deprive many families of comfort and of sustenance?-to impede the current of national prosperity ?—to nourish with British capital the roots of maritime power in some rival state?—and, at his own risk," who remains snugly at home, to expose many British crews to the hazards of the sea in unsound bottoms-in ships which he knows ous and most laborious artisans "are known" to get from 70l. to 90l. a-year. It is known. The atrocious fact is laid before the blushing sun. O, unexampled rapacity of gain! O, insatiate vultures on the public purse! Is it known, also, how many thousands were unavoidably and properly dismissed from the public service at the blessed peace? and under what the trade has lain patiently for a cloud of privation and distress years, until, lately, the revival of their labours, and enabled the shipcommerce has opened a field for owner to render them a fair remuneration? The art of building having declined here, under the policy of such men, will their grandsons be ready, when Heaven shall afflict us with war, to send to these same continental ports for seventy-fours IMPROVED STEAM-ENGINE BUCKET, ETC. and stout frigates to recruit the navy? I now retire, for the sake of fair play, not because my heart is And remain, empty, SIR,-Some years back, I was much inconvenienced in the work ing of a steam-engine of about thirty-five horse power, by not being able to get sufficient cold water to condense. My pump seemed to be too small, and the situation of the well, and other local circumstances, made it impracticable to have a larger pump, or to lengthen the stroke, without great expense and alteration. I consequently constructed a new sort of clack and bucket, whereby I thought more water could be brought up, well knowing that much water is lost through the ordinary clacks, and afterwards through the buckets, in bringing it up from the working part of the barrel or pump-tree. The result answered my most sanguine expectation. The vacuum I formed was stronger; the quantity of water I brought up was very considerably more than before, and for four years (since which I first adopted the plan) I have had plenty of water. I have shown the bucket to several scientific people, who all spoke very well of it. Continuing to find great benefit from it, I thought it, at last, a pity that it should not be made better known. I therefore made not only a communication of it to the Society of Arts, but mounted a six-inch bucket complete, which I sent to that learned body. The result was, that after it passed the examination of their Committee, no merit 207 was found in the contrivance, and I got my bucket back. This did not surprise me, because I am well convinced that man generally overrates his own talents; but what did surprise me, was, that the silver Isis medal was at the same time presented by the Society of Arts to a gentleman, for the invention of a Painter's Rest, to be used as a substitute for the common maul-stick. This said rest is upon the principle of a fire-screen, which vertically slides up and down.Now you must know, Mr. Editor, that in my younger days I was an amateur painter in the Netherlands; Mr. La Croix, of Bruges, was my instructor; and I was intimate with Solvyns, of Antwerp, and several other eminent painters of that day, and I venture to assert boldly, that the said painter's rest is totally unfit for its intended purpose, if the painting is to be of any size above a few inches. Sir Joshua Reynolds and Hickel (the latter I was personally acquainted with) would have laughed at this painter's rest; because the maulstick serves not only as a rest, but also as a lever of the second order. The fulcrum is at that end which, muffled, rests on the canvas or pannel; the rest of the arm is the weight, and by the power of the hand at the other end the rest is conveyed in all the necessary directions, which cannot be done with the aforementioned newly-invented rest, without constantly shifting the machine, and painting at the same time! The maul-stick performs another duty-it is a hold and rest for the hand that carries the pallet. I beg you to excuse this digression. To return to my bucket, I have only further to say, that its good qualities chiefly consist in this, that nothing can obstruct the entrance of the fluid, as in other large buckets. The entrance is clear and free; the clacks or doors, which are of brass, are so fitted as to make a perfect joint which holds water; and the longer it works, the closer these doors bed themselves. The gudgeons do not |