30 DEVELOPMENT OF ELECTRICITY IN MANUFACTURING PROCESSES. height, in most respects similar to the cast iron lamp-posts ordinarily employed for gaslighting, should be erected at each station; and around each pedestal, at the depth of a foot or eighteen inches beneath the surface of the earth, should be buried a voltaic battery, consisting of several thousand pairs of plates, arranged as in our last-mentioned experiment (21). 2. It would seem desirable that the plates constituting each battery series should be deposited vertically around each station, in the form of a narrow ellipsis, the respective ends terminating near to, and one on each side of, the hollow pedestal, within which, properly defended from contact, the conducting wires might ascend into a glass globe fitted for the reception of carbon points, from which the voltaic lights are to proceed. 3. Under all considerations, the best and most durable material for exhibiting voltaic light appears to be gas carbon. Small cylinders of this substance, three or four inches in length, and perhaps the tenth or twelfth of an inch in diameter, formed like the leads (plumbago) of the "ever-pointed pencil, might be advanced towards each other, and withdrawn at pleasure, through hollow metallic cases, opposed to one another, and passing through the sides of the glass globe, outside of which their distance within might be regulated by means of a very simple mechanical contrivance. The globe itself should be screwed on to the top of the pillar, from which it might be readily detached for the purpose of occasionally renewing the carbon points, &c. 4. In as far as experiments have yet determined, the use of copper as a negative metal ought not to be adopted; while it seems that iron may be substituted, as being not only more economical, but at least equal, if not superior, in effect; or, probably, M. Bunsen's prepared carbon plates might be found more advantageous than either copper or iron. One of the principal features of recommendation in a subterraneous battery is the uniformity of its action. To the duration of the positive metals there must necessarily, however, be a limit; but if they were at first deposited of considerable thickness, suppose five-tenths of an inch for instance, so slow and regular is the rate of their action, that a battery might reasonably be expected to continue in operation through many successive years. 5. It does not appear difficult to keep the glass globes, suggested to contain the voltaic lights, exhausted of air, as is said to have been the case in the late Parisian experiment, performed by the aid of two hundred carbon and zink elements, excited with nitric acid on one side, and sulphuric acid diluted on the other; but the advantages of exhaustion, if any, would be more than counterbalanced by extra expenses in apparatus and attention. 6. It were, perhaps, possible to furnish a vast number of voltaic lights within a district with an adequate current of electricity from a single battery upon an enormous scale, as gas-lights are supplied from a single reservoir; but in this way the passage of the current would be much more liable to derangement, without its being so easy to discover in what part of the conductors the injury or defect had taken place. A battery appropriated to the production of each light seems the more eligible plan; and, upon a rough estimate, it does not appear that the primary arrangements of the voltaic system would exceed, if indeed they would equal, the first outlay of a gas-manufactory, its main and branch pipes, &c., and when once complete, the expense of the voltaic lights would amount to a comparative fraction. 7. The foregoing observations, it may be presumed, will sufficiently illustrate the practical application of the few principles advocated in this paper, which I will conclude with an additional remark. Let subterraneous batteries, each composed of some eighty or a hundred thousand pairs of voltaic plates, be formed around our principal lighthouses, with conductors to convey the electric current to a suitable apparatus on the summit of the respective structures-its cost, in a national point of view, would be insignificant and then we might hope to produce a beacon worthy of being called "the light of all nations.' ON THE ELECTRICITY DEVELOPED IN THE MANUFACTURE OF MACHINE-MADE PAPER. BY DR. HANKEL. FROM POGGENDORFF'S ANNALES, AS TRANSLATED IN MR. WALKER'S "ELECTRICAL MAGAZINE," FOR JANUARY, 1845. That paper, when warmed, and afterwards rubbed on a table with a brush or with Indian-rubber, presents very marked electric indications, is an experiment which is undoubtedly very well known. However, I think that the following short notice of the appearance of very powerful negative electricity, during the manufacture of machine-paper, will be interesting. This phenomenon was mentioned to me by M. Keferstein, a papermaker at Krollwitz, near Halle; and I have myself had the opportunity of observing the same. When the paper has left the rockingtable, and the water has partly run through the wire-frame that passes, on an endless ROLLER ESCAPEMENTS. band, over a couple of rollers, and is then pressed out by a roller placed near the wireframe; the paper thus made still remains damp, although it possesses some degree of solidity; it thence passes over to the rollers, which are heated by steam, and is accompanied among the first three by a hair-cloth, but goes over the fourth without the aid of a hair-cloth; after it has gone between the last pressing rollers, the very wide paper sheet is cut into three narrow strips, of the width of an ordinary sheet of paper, by sharp circular cutters placed in a roller, and it is then rolled upon a cylinder. So long as the paper is accompanied by the haircloth, no signs of electricity are manifested; they appear when it leaves the last steamroller, or rather the last pressing-roller. It appears by experiment that the heat of the last steam-roller exercises great influence, inasmuch as the electrical phenomena are much stronger the more the heat of the last steam-roller is increased; they are frequently so strong that very loud sparks dart from the paper to the last smoothing-roller (a small guiding-roller of copper), and to the roller on which the cutters are fixed. the finger is brought near to the paper, a rapid succession of small sparks are perceived to pass from it to the paper. A Leyden jar can easily be charged. The electricity remains in the paper for a considerable time. If When only a few coils of paper are on the cylinder, the electricity is feeble; but it increases considerably with the number of folds. If the paper is cut away from the cylinder, and the long strips are thrown asunder, many strong and very brilliant sparks fly between them. This electricity is evidently produced merely by the heating of the paper, and its being pressed by means of the rollers. No friction can take place, because the velocity of the circumference of all the rollers is exactly the same. The evaporation of water is certainly no cause of the electricity appearing at the end of the machine; since, just in those parts where the evaporation is the strongest, no signs of electricity are manifested; and the damp paper, being a conductor, conveys all that is so produced to the metal rollers. Note.-Compare Gib. Ann., vol. lxxv. p. 197.-I take the liberty of observing, that the appearance of electricity in the fabrication of is no new phenomenon: probably paper there are few proprietors of such manufactories who have not noticed it, as it is even a hindrance in folding the paper. In the meanwhile, this phenomenon has not been mentioned in the Annalen; nor, so far as I can discover, has it been noticed in works on natural philosophy; on which account the circumstance may be unknown to many readers of this journal. 31 A similar production of electricity has for many years been noticed in Mr. Macintosh's manufactory at Glasgow, on tearing asunder the well-known water-proof cloth, which is stuck together by means of a solution of Indian-rubber in coal-tar.*-(Edin. Phil. Jour. vol. x., p. 185.) Lately, also, they have been seen by Mr. Marsh, at Woolwich, on grinding newly roasted coffee in an iron coffee-mill; they passed between the mill and a tin can placed one-tenth of an inch distant.(Ann. of Elect. vol. viii. p. 124.) Lastly, a very strong attraction has been noticed in a cotton-mill, in a broad endless band, that passes horizontally over two cylinders of almost 3 feet in diameter, which revolves seventy-two times in a minute.-Cottonwool was attracted from a distance of two or three feet; and, four feet beneath the band, the hair of the workmen stood on end.— (Ann of Elect, vol. v., p. 397.)—Editor of the Annalen. ROLLER ESCAPEMENTS. Sir,-Your correspondent, Mr. Arthur Trevelyan, will much oblige by stating where the paper by Sir John Robison on Whitelaw's escapement, of which he speaks, has been published. I should much like to see it, as I have never seen or heard of any other than Wynn's escapement, in which rollers have been applied. I have these last two or three years employed my leisure time in perfecting an escapement with rollers, and have at last brought it to that state of perfection which satisfies me that it will be brought into general use. I should, therefore, like to see the attempt of another. I am, Sir, your obedient servant, Chronometer Maker. 148, Leadenhall-street, Jan. 8, 1845. THE ARTS OF DESIGN IN ENGLAND AND FRANCE. The Committee of Management of the Government School of Design, Somerset House, caused purchases to be made, at the late Paris Exposition of Arts and Manufactures, of whatever articles seemed most deserving of imitation at home for their elegance or ingenuity; and two weeks ago they sent down to Manchester several large cases filled with such articles, in order to their being exposed to public view at an exhibition of manufactures which has been recently got up by the Me * We may mention that the two cloths are passed between two steam-rollers highly heated; and that the adhesive solution is between the cloths as they enter the rollers.-Ed. Elec. Mag. 32 THE ARTS OF DESIGN IN ENGLAND AND FRANCE. chanics' Institution of that place. The local papers state that, after they have been on view at Manchester for a fortnight, they are to be successively exhibited at Glasgow, Edinburgh, Birmingham, and other large towns where Schools of Design have been established. The managers of our Government School are in this acting very judiciously and usefully. The Manchester Guardian makes some remarks on these specimens of foreign skill which are deserving of universal attention : "These specimens strikingly illustrate, not only the application of taste to manufactures, but the extraordinary and rapid progress the French are making in various important branches of trade. In bronze casting, porcelain, and silk, they have long excelled; but amongst these specimens, their progress is also apparent and surprising in carpet weaving of the commoner sorts, in damask weaving, and in the fabric of plate. In earthenware there is also much that we might learn from the specimens sent. Amongst the metal vases, we may notice one of bronze, with allegorical groups representing "Justice and Peace embracing," "Patience," "Hope," &c., these figures being modelled by the sculptor of the doors of the Madeline, at Paris-a significant fact, showing that in France the first artists do not disdain to employ their talents upon even small works of decorative art. A small silver vase is another beautiful specimen. It is formed of a metal called by the French argent platiné (consisting of four parts silver and one platina), and is a charming specimen of elegant design and workmanship. The chasing is exquisitely executed, and the workmen in this art, we are told, are educated in the schools of design, and receive, in Paris, high wages; in some cases from ten to fifteen francs a day (8s. to 12s.). The facility with which the French sculptor may get his works cast in bronze, and the moderate cost of the operation, are striking advantages over us. A statue, about three feet high, may be cast in Paris for about 301. sterling. A cast of the " Mercury" of John Bologna, in bronze, of the size of the original, may be had in Paris for 407.; a colossal statue, nine feet high, may be cast in iron for about 2407., and in bronze for about twice that sum; and a colossal bronze equestrian statue may be cast for about 50,000 francs, or 2,000l. Amongst other subjects for ornamental design and embellishment are various locks and hinges. The French do not sink their locks in the door, like our mortice locks, but put them outside and projecting, and so lavish much ornament and fitting embellishment upon them. Some are got up in gilded metalrelieved by japanning; others in bronze, and one in iron is an excellent specimen, not only of clever design, but of excellent casting. There is a blue vase from Sevres, called the Adelaide Vase. This beautiful vase is painted in imitation of the celebrated old enamels of Limoges. We understand that there is nothing in the actual manufacture, colour, or gilding of this vase that could not be as perfectly done in this country; but the taste of the design, and the artist-like skill of the painting, are superior to those of our productions. * * One of the most beautiful specimens we have ever seen of the manner in which French designers execute drawings for the manufacturers, is shown in the drawing for a rug. It is a richly floral design; and it is astonishing how exquisitely graceful and pleasing an effect the designer has conveyed in a pattern which is very full, not to say crowded, with every variety of flowers in bouquets, wreaths, &c. The colours, too, notwithstanding their variety, are in delightful harmony. Let any one examine carefully this drawing, and then connect it with the fact that the French manufacturer often pays as much as 401. for a design for a carpet, and he will no * * longer wonder at the success of the French in de Earliest Print Known.-The earliest engraving hitherto known, which represents St. Christopher bearing the Infant Jesus on his shoulders, is marked with the year 1423; but an accident has carried this date five years backward. A few weeks ago some person at Malines, who was about to burn an old chest which contained a quantity of mouldy papers, perceived, pasted on the inside of the lid, a print which was become very obscure from dirt and age. A person, however, was present, who had a knowledge of prints, and who carefully took off the fragments; and, having united them again, found clearly marked the date of 1418. This rare specimen, which belongs to the Flemish School, has been purchased for the Royal Library at Brussels, at the price of 500fr. INTENDING PATENTEES may be supplied gratis with Instructions, by application (post paid) to Messrs. Robertson and Co., 166, Fleet-street, by whom is kept the only COMPLETE REGISTRY OF PATENTS. LONDON: Printed and Published by James Bounsall, at the Mechanics' Magazine Office, WARD, COLBOURNE AND GILLET'S IMPROVED CHAFF-CUTTING MACHINE. Fig. 2. Fig. 1. VOL. XLII. Mechanics' Magazine, MUSEUM, REGISTER, JOURNAL, AND GAZETTE. No. 1119.] SATURDAY, JANUARY 18, 1845. [Price 3d. A MESSRS. WARD, COLBOURNE AND GILLET'S IMPROVED CHAFF-CUTTING MACHINE. [Registered under the Act for the Protection of Articles of Utility. James Ward and William Colbourne, of Stratford on Avon, and John Gillet, of Brails, Warwickshire, Proprietors.] THIS is a very skilfully contrived machine, and will be found to possess several important advantages over others of the same class. Fig. 1 is an end elevation and fig. 2 a side elevation of it. A is a wooden frame, and B B a frame of iron bolted to the top of the former. Cis an axis, which turns in bearings in the iron standards D D. EE are the wheels which carry the knives, K K, fixed on the axis C. F is a fly-wheel attached to the outer end of the axis C, and G a double cogged cam, which is fixed on the opposite end. H is the feed-box, and J its mouth-piece. L L are the rollers. M1 and N1 a pair of toothed wheels fixed on the inner end of the axis of the lower roller; and M2 N2 another pair of toothed wheels fixed on the inner end of the axis of the upper roller. P is a wheel with concave teeth fixed on the axis of the lower roller, or inside of the pair of wheels, M1 N1, into which wheel, P, works the cam G, the plain parts of the periphery of this cam fitting the concave surfaces of the teeth of the wheel P, and its two cogs taking into the space between the teeth. On the machine being set to work, each revolution of the fly-wheel F, The The principal advantages gained by these arrangements are, that the material to be cut gets a firmer bearing, the material standing still while the knives are cutting; that the knives have a much greater drawing cut, and may be adjusted to cut the material either long or short, as required. The parts peculiar to this machine are the cam G, the concave toothed wheel P, knives, K K, and the wheels, M1 M2 and N1 N2. CENTROBARIC MENSURATION. It has long appeared to us a remarkable circumstance, that amongst the numerous writers on the principles of Mensuration, not one of them has viewed it in connection with the properties of the centre of gravity. It would be altogether inconsistent with the plan of an elementary work to consider the subject in this way, as it presupposes a knowledge of the first principles of mechanical science; but in the more profound and extensive treatises which have from time to time appeared, the theory might have been discussed, and the applications pointed out to their full extent, without the risk of falling into any inconsistency, or of violating the maxims of rigorous system in the smallest degree. It, however, appears, that none of those who might in every respect be considered as competent to the task, have thought it worth the while to draw up a treatise on the subject; and accordingly, in so far as the English language is concerned, we look in vain for an independent work, bearing the title of CENTROBARIC MENSURATION. The utility of such a performance cannot be questioned, for the facility with which the rules of calculation are deduced is very surprising; and the inverse case of the problem is of the greatest importance in numerous departments of mechanical inquiry, affording, as it does, a ready and expeditious method of determining the position of that point, into which the constituent matter of every body possessing weight or gravity is conceived to be collected. Emerson, in his customary quaint style of expression, has faintly shadowed out the principle in a corollary to the 55th proposition of his Mechanics; he, however, leaves the development and application to the sagacity of his readers. The enunciation runs thus: "If a line, right or curve, or any |