moving upwards to push back the crank, A. It cannot do so, however, till the crank has fallen a little (as, to the dotted lines, C). Now, look at the other wheel and you will see the crank, D, is just in such a position, that the rod, E, can pull it towards the cylinder with all its might, and the piston is at the top of the cylinder, B Fig. 8. ready to go down again and pull the spoke of the wheel towards it; in doing so it will also turn the other wheel until it has got it into position for its comrade piston to push it back. Then the other wheel pulls the upper spoke of its wheel, while its companion pushes back the lower spoke of the corresponding one. You will now be able to understand the working of an engine, and if you look on each side of a locomotive the next time you go to a railway station, you will see these two cylinders, which I have been describing.-Rev. J. Ridgway. MACHINERY AT THE INTERNATIONAL MACHINERY used in connexion with cotton and cotton fabrics, with paper, stationery, and printing, is arranged in the rooms on the ground floor of the West Galleries, in the "East Machinery Annexe," and in rooms at the south-east corner of the Exhibition. The visitor at all familiar with the manufactures, the processes of which are thus represented, will, except in the printing depart ment, not find very much that is new to him, but those who have never been in the way of such knowledge will follow with interest the folding of an envelope, the printing of an engraving, or the winding and weaving of cotton yarn. Beginning with the cotton machinery in Room I. of the West Galleries, we take the opportunity of turning aside to the cotton-growing house in the West Grounds, in which Major Trevor Clarke exhibits varieties of American, Asian, and African cotton. The tall, graceful plants are just coming into flower, and seem to thrive well in their pots and in a hot-house air at 95 deg. Persons inclined to take a lesson in commercial botany in such a class-room may study the similarities and differences between the several growths of Borneo, China, Assam, and India, and those of the most favoured American soils. Returning to the West Gallery, Room I. begins with 25 varieties of dried cotton in glass cases, also exhibited by Major Clarke, and with a case illustrating every stage in cotton manufactures, from the plant to the woven calico. Near at hand are samples of cotton from those South Sea Islands, which must one day be the Indies of Australia; cotton cleaned by patients in the Palermo Lunatic Asylum; cotton pods from Algeria, Egypt, Aleppo, Peru, the Bahamas, Italy, Ceylon, Trinidad, Abyssinia, Queensland, and every other soil, (whether North, South, East, or West), which nourishes the plant that not only clothes mankind, but is ready to feed the lower animals; witness "cotton-seed cake for cattle food." Turning to the machinery, we may contrast the cotton-cleaning "churkas" from India, lent by the Secretary of State, with the new machine for the same purpose exhibited by Platt Brothers. Into Room II. we pass from cotton to paper, and the general visitor may here watch, with some gleams of intelligence, the different processes of fine art and letterpress printing, and may catch a glimpse in advance of the Good Words' engravings. Turning to the other side, we have the not less ingenious, if more commonplace, ruling of account books practised by Letts and Co. The blue ink runs from a saturated flannel down fluted pens set in a row, and the paper takes its lines as it is drawn quickly under these. Entering Room III., we find almost the whole of the left side occupied by John Dickinson and Co.'s envelope machinery, shewing us the complete process of envelope making, beginning at the "web," or endless roll of paper, and ending with the finished envelopes in packets. First of all, here is the paper, as it arrives from the mill in rolls, which can be made of one continuous sheet several miles long, but which, for convenience sake, are limited to a weight of 4 cwt. and a length of three-quarters of a mile. This sheet is fixed to the "cutting machine." The cutters can be altered to any size, and nothing can exceed the celerity and convenience of their action. The paper leaves them in a state too rough for writing purposes, and has next to be "glazed." This gives it the required surface, and we next see it being punched into "blanks" (the shape of an envelope open at all sides) at a small press; then comes the "gumming on the nose," which is done by girls at the rate of 40,000 an hour, or about one a second; then the stamping in relief or cameo, the blackbordering (for mourning stationery), and, finally, the folding, done at two machines which work on different principles. Man's ingenuity seems to have exhausted itself in devising machines to fold envelopes, and in this room several patents may be seen doing the same work in different modes. By the account of the makers, each is in some way the very best machine of all, and by our own observation each appears to do its work marvellously well. Messrs. Dickinson shew us also the banding of the envelopes in packets, the making of boxes for those which are black-bordered, and tell us that their machines in this room will turn out 300,000 and more finished envelopes in one day. Messrs. Goodall fold and finish envelopes, with extreme neatness and fascinating precision, in a machine which stamps the blanks" into shape in the successive apertures of a revolving dial. Messrs. Willis chop countless playing cards into their exact width from long strips of cardboard; and Messrs. Fenner turn out from their machine sixty complete envelopes a minute. We do not know that we can give our readers a better idea how manifold and complex mechanism is made to do the work of human fingers, than by quoting the account of the working of this rapid little engine: "A pile of envelope blanks is placed upon a plate on the left-hand side of the machine, which may be done either when at rest or when in motion. A hollow brass tube, with the end of a peculiar shape, descends upon the envelope blanks at the side nearest to the foldingbox; to the other end of the tube is attached an indiarubber pipe communicating with an air-pump, which, coming into action at this instant, causes the blank which is upon the top of the pile to attach itself to the brass tube, which, rising, carries the envelope blank with it; a pair of grippers then run forward, and, seizing the blank, carry it into its proper position over the folding-box; it is then stamped, and the gum applied in the proper places upon the two side flaps. A plunger then descends and carries the blank into the foldingbox; upon the plunger rising, slides, working in the thickness of the folding-box, run in and enclose the flaps in their proper order; the bottom of the box now rises and completes the operation by pressing the envelopes against the slides; the bottom of the box then falls and allows the envelope to drop in an upright position into a trough running under the machine, when it is met by a simple contrivance, which secures the envelope with its flaps in their proper position in the trough, and as each successive envelope is placed in front of it, it gradually works along the trough, until removed by the attendant and banded." Here also the Graphotyping Company exhibit their exceedingly ingenious method of engraving. In graphotype the artist draws with chymical ink upon a surface of prepared chalk, which has been sifted upon a zinc plate and compressed by hydraulic power so as to give a smooth surface. The ink is prepared so as to harden the chalk wherever it touches it; when the sketch is completed, the spaces between the lines are removed by a soft brush; the drawing, thus left in relief, is washed in a chymical solution which renders it as hard as stone; a mould is then taken, and from that again an electrotype ready for printing. "THE WALTER" PRINTING PRESS. THE Composing and distributing machines, exhibited by Mr. Walter, call for special notice, since they are both effective and new, and likely to come into use. The distributing machine is the more remarkable, as being exceedingly simple, and yet the first instance in which such a machine has been brought to do good work. Composing machines of more or less clever construction have been from time to time patented, but the bar to their use has always been that either the type had to be distributed by hand, which necessitated the retention of a staff of compositors, or that, if distributed by a machine, the type was required to be of some special construction. The new machines work with the ordinary type, and when we say that they are now in use in The Times Office, and that the composing machine is worked by two boys, who can compose as fast as three highly-skilled compositors, and that the distributing machine, worked by one lad, can distribute rather faster than a highlyskilled compositor, the value and importance of this patent will be at once seen. A new invention cannot well be described without illustrations, but it will give our readers some idea of these machines if we say that in the composing machine the different letters, &c., are arranged vertically in a series of cases just of a size to hold them, and in connection with pianoforte-like keys. Before these a lad sits, and as he reads his copy so he strikes a key with his finger, upon which the letter wanted drops into its place in a groove. In this groove |