Dr. Lilienthal, a German, was the first to try scientific wing-sailing. He became a regular air gymnast, running down the sides of an artificial mound until the wings lifted him up and enabled him to float a considerable distance before reaching earth again. His wings had an area of 160 square feet, or about a foot to every pound weight. He was killed by the wings collapsing in mid-air. A similar fate also overtook Mr. Percy Pilcher, who abandoned the initial run down a sloping surface in favour of being towed on a rope attached to a fast-moving vehicle. At present Mr. Octave Chanute, of Chicago, is the most distinguished member of the "gliding" school. He employs, instead of wings, a species of kite made up of a number of small aerocurves placed one on the top of another a small distance apart.

These box kites are said to give a great lifting force for their weight.

These and many other experimenters have had the same object in view--to learn the laws of equilibrium in the air. Until these are fully understood the construction of large flying-machines must be regarded as somewhat premature. Man must walk before he can run, and balance himself before he can fly.

There is no falling off in the number of aerial machines and schemes brought from time to time into public notice. We may a.s.sure ourselves that if patient work and experiment can do it the problem of "how to fly" is not very far from solution at the present moment.

As a sign of the times, the War Office, not usually very ready to take up a new idea, has interested itself in the airship, and commissioned Dr. F. A. Barton to construct a dirigible balloon which combines the two systems of aerostation. Propulsion is effected by six sets of triple propellers, three on each side. Ascent is brought about partly by a balloon 180 feet long, containing 156,000 cubic feet of hydrogen, partly by nine aeroplanes having a total superficial area of nearly 2000 square feet. The utilisation of these aeroplanes obviates the necessity to throw out ballast to rise, or to let out gas for a descent. The airship, being just heavier than air, is raised by the 135 horse-power motors pressing the aeroplanes against the air at the proper angle. In descent they act as parachutes.

The most original feature of this war balloon is the automatic water-balance. At each end of the "deck" is a tank holding forty gallons of water. Two pumps circulate water through these tanks, the amount sent into a tank being regulated by a heavy pendulum which turns on the c.o.c.k leading to the end which may be highest in proportion as it turns off that leading to the lower end. The idea is very ingenious, and should work successfully when the time of trial comes.

Valuable money prizes will be competed for by aeronauts at the coming World's Fair at St. Louis in 1903. Sir Hiram Maxim has expressed an intention of spending 20,000 in further experiments and prizes. In this country, too, certain journals have offered large rewards to any aeronaut who shall make prescribed journeys in a given time. It has also been suggested that aeronautical research should be endowed by the state, since England has nothing to fear more than the flying machine and the submarine boat, each of which tends to rob her of the advantages of being an island by exposing her to unexpected and unseen attacks.

Tennyson, in a fine pa.s.sage in "Locksley Hall," turns a poetical eye towards the future. This is what he sees--

"For I dipt into the future, far as human eye could see, Saw the vision of the world and all the wonder that would be, Saw the heavens fill with commerce, argosies of magic sail, Pilots of the purple twilight dropping down with costly bales, Heard the heavens fill with shouting, then there rained a ghostly dew, From the nations' airy navies, grappling in the central blue."

Expressed in more prosaic language, the flying-machine will primarily be used for military purposes. A country cannot spread a metal umbrella over itself to protect its towns from explosives dropped from the clouds.

Mail services will be revolutionised. The pleasure aerodrome will take the place of the yacht and motor-car, affording grand opportunities for the mountaineer and explorer (if the latter could find anything new to explore). Then there will also be a direct route to the North Pole over the top of those terrible icefields that have cost civilisation so many gallant lives. And possibly the ease of transit will bring the nations closer together, and produce good-fellowship and concord among them. It is pleasanter to regard the flying-machine of the future as a bringer of peace than as a novel means of spreading death and destruction.

TYPE-SETTING BY MACHINERY.

To the a.s.syrian brickmakers who, thousands of years ago, used blocks wherewith to impress on their unbaked bricks hieroglyphics and symbolical characters, must be attributed the first hesitating step towards that most marvellous and revolutionary of human discoveries--the art of printing. Not, however, till the early part of the fifteenth century did Gutenberg and Coster conceive the brilliant but simple idea of printing from separate types, which could be set in different orders and combinations to represent different ideas. For Englishmen, 1474 deserves to rank with 1815, as in that year a very Waterloo was won on English soil against the forces of ignorance and oppression, though the effects of the victory were not at once evident. Considering the stir made at the time by the appearance of Caxton's first book at Westminster, it seems strange that an invention of such importance as the printing-press should have been frowned upon by those in power, and so discouraged that for nearly two centuries printing remained an ill-used and unprogressive art, a giant half strangled in his cradle. Yet as soon as prejudice gave it an open field, improved methods followed close on one another's heels. To-day we have in the place of Caxton's rude hand-made press great cylinder machines capable of absorbing paper by the mile, and grinding out 20,000 impressions an hour as easily as a child can unwind a reel of cotton.

Side by side with the problem how to produce the greatest possible number of copies in a given time from one machine, has arisen another:--how to set up type with a proportionate rapidity. A press without type is as useless as a chaff-cutter without hay or straw. The type once a.s.sembled, as many casts or stereotypes can be made from it as there are machines to be worked. But to arrange a large body of type in a short time brings the printer face to face with the need of employing the expensive services of a small army of compositors--unless he can attain his end by some equally efficient and less costly means. For the last century a struggle has been in progress between the machine compositor and the human compositor, mechanical ingenuity against eye and brains. In the last five years the battle has turned most decidedly in favour of the machine. To-day there are in existence two wonderful contrivances which enable a man to set up type six times as fast as he could by hand from a box of type, with an ease that reminds one of the mythical machine for the conversion of live pigs into strings of sausages by an uninterrupted series of movements.

These machines are called respectively the Linotype and Monotype.

Roughly described, they are to the compositor what a typewriter is to a clerk--forming words in obedience to the depression of keys on a keyboard. But whereas the typewriter merely imprints a single character on paper, the linotype and monotype cast, deliver, and set up type from which an indefinite number of impressions can be taken.

They meet the compositor more than half-way, and simplify his labour while hugely increasing his productiveness.

As far back as 1842 periodicals were mechanically composed by a machine which is now practically forgotten. Since that time hundreds of other inventions have been patented, and some scores of different machines tried, though with small success in most cases; as it was found that quality of composition was sacrificed to quant.i.ty, and that what at first appeared a short cut to the printing-press was after all the longest way round, when corrections had all been attended to. A really economical type-setter must be accurate as well as prolific.

Slipshod work will not pay in the long run.

Such a machine was perfected a few years ago by Ottmar Mergenthaler of Baltimore, who devised the plan of casting a whole _line of type_. The Linotype Composing Machine, to give it its full t.i.tle, produces type all ready for the presses in "slugs" or lines--hence the name, Lin' o'

type. It deserves at least a short description.

The Linotype occupies about six square feet of floor s.p.a.ce, weighs one ton, and is entirely operated by one man. Its most prominent features are a sloping magazine at the top to hold the bra.s.s matrices, or dies from which the type is cast, a keyboard controlling the machinery to drop and collect the dies, and a long lever which restores the dies to the magazine when done with.

[Ill.u.s.tration: _By kind permission of The Linotype Co._

_The Linotype Machine. By pressing keys on the key-board the operator causes lines of type to be set up, cast, and arranged on the "galley"

ready for the printers._]

The operator sits facing the keyboard, in which are ninety keys, variously coloured to distinguish the different kinds of letters. His hands twinkle over the keys, and the bra.s.s dies fly into place. When a key is depressed a die shoots from the magazine on to a travelling belt and is whirled off to the a.s.sembling-box. Each die is a flat, oblong bra.s.s plate, of a thickness varying with the letter, having a large V-shaped notch in the top, and the letter cut half-way down on one of the longer sides. A corresponding letter is stamped on the side nearest to the operator so that he may see what he is doing and make needful corrections.

As soon as a word is complete, he touches the "s.p.a.cing" lever at the side of the keyboard. The action causes a "s.p.a.ce" to be placed against the last die to separate it from the following word. The operations are repeated until the tinkle of a bell warns him that, though there may be room for one or two more letters, the line will not admit another whole syllable. The line must therefore be "justified," that is, the s.p.a.ces between the words increased till the vacant room is filled in. In hand composition this takes a considerable time, and is irksome; but at the linotype the operator merely twists a handle and the wedge-shaped "s.p.a.ces," placed thin end upwards, are driven up simultaneously, giving the lateral expansion required to make the line of the right measure.

A word about the "s.p.a.ces," or s.p.a.ce-bands. Were each a single wedge the pressure would be on the bottom only of the dies, and their tops, being able to move slightly, would admit lead between them. To obviate this a small second wedge, thin end _downwards_, is arranged to slide on the larger wedge, so that in all positions parallelism is secured.

This smaller wedge is of the same shape as the dies and remains stationary in line with them, the larger one only moving.

The line of dies being now complete, it is automatically borne off and pressed into contact with the casting wheel. This wheel, revolving on its centre, has a slit in it corresponding in length and width to the size of line required. At first the slit is horizontal, and the dies fit against it so that the row of sunk letters on the faces are in the exact position to receive the molten lead, which is squirted through the slit from behind by an automatic pump, supplied from a metal-pot.

The pot is kept at a proper heat of 550 Fahrenheit by the flames of a Bunsen burner.

The lead solidifies in an instant, and the "slug" of type is ready for removal, after its back has been carefully trimmed by a knife. The wheel revolves for a quarter-turn, bringing the slit into a vertical position; a punch drives out the "slug," which is slid into the galley to join its predecessors. The wheel then resumes its former horizontal position in readiness for another cast.

The a.s.sembled dies have for the time done their work and must be returned to the magazine. The mechanism used to effect this is peculiarly ingenious.

An arm carrying a ribbed bar descends. The dies are pushed up, leaving the "s.p.a.ces" behind to be restored to their proper compartment, till on a level with the ribbed bar, on to which they are slid by a lateral movement, the notches of the V-shaped opening in the top side of each die engaging with the ribs on the bar. The bar then ascends till it is in line with a longer bar of like section pa.s.sing over the open top of the entire magazine. A set of horizontal screw-bars, rotating at high speed, transfer the dies from the short to the long bar, along which they move till, as a die comes above its proper division of the magazine, the arrangement of the teeth allows it to drop. While all this has been going on, the operator has composed another line of moulds, which will in turn be transferred to the casting wheel, and then back to the magazine. So that the three operations of composing, casting, and sorting moulds are in progress simultaneously in different parts of the machine; with the result that as many as 20,000 letters can be formed by an expert in the s.p.a.ce of an hour, against the 1500 letters of a skilled hand compositor.

How about corrections? Even a comma too few or too many needs the whole line cast over again. It is a convincing proof of the difference in speed between the two methods that a column of type can be corrected much faster by the machine, handicapped as it is by its solid "slugs," than by hand. No wonder then that more than 1000 linotypes are to be found in the printing offices of Great Britain.

The Monotype, like the Linotype, aims at speed in composition, but in its mechanism it differs essentially from the linotype. In the first place, the apparatus is constructed in two quite separate parts. There is a keyboard, which may be on the third floor of the printing offices, and the casting machine, which ceaselessly casts and sets type in the bas.e.m.e.nt. Yet they are but one whole. The connecting link is the long strip of paper punched by the keyboard mechanism, and then transferred to the casting machine to bring about the formation of type. The keyboard is the servant of man; the casting machine is the slave of the keyboard.

Secondly, the Monotype casts type, not in blocks or a whole line, but in separate letters. It is thus a complete type-foundry. Order it to cast G's and it will turn them out by the thousand till another letter is required.

Thirdly, by means of the punched paper roll, the same type can be set up time after time without a second recourse to the keyboard, just as a tune is ground repeatedly out of a barrel organ.

The keyboard has a formidable appearance. It contains 225 keys, providing as many characters; also thirty keys to regulate the s.p.a.cing of the words. At the back of the machine a roll of paper runs over rollers and above a row of thirty little punches worked by the keys.

A key being depressed, an opened valve admits air into two cylinders, each driving a punch. The punches fly up and cut two neat little holes in the paper. The roll then moves forward for the next letter. At the end of the word a special lever is used to register a s.p.a.ce, and so on to the end of the line. The operator then consults an automatic indicator which tells him exactly how much s.p.a.ce is left, and how much too long or too short the line would be if the s.p.a.ces were of the normal size. Supposing, for instance, that there are ten s.p.a.ces, and that there is one-tenth of an inch to spare. It is obvious that by extending each s.p.a.ce one-hundredth of an inch the vacant room will be exactly filled. Similarly, if the ten normal s.p.a.ces would make the line one-tenth of an inch too _long_, by _decreasing_ the s.p.a.ces each one-hundredth inch the line will also be "justified."

[Ill.u.s.tration: _By kind permission of_] [_The Monotype Co._

_The Monotype Casting Machine. A punched paper roll fed through the top of the machine automatically casts and sets up type in separate letters._]

But the operator need not trouble his head about calculations of this kind. His indicator, a vertical cylinder covered with tiny squares, in each of which are printed two figures, tell him exactly what he has to do. On pressing a certain key the cylinder revolves and comes to rest with the tip of a pointer over a square. The operator at once presses down the keys bearing the numbers printed on that square, confident that the line will be of the proper length.

As soon as the roll is finished, it is detached from the keyboard and introduced to the casting machine. Hitherto pa.s.sive, it now becomes active. Having been placed in position on the rollers it is slowly unwound by the machinery. The paper pa.s.ses over a hollow bar in which there are as many holes as there were punches in the keyboard, and in precisely the same position. When a hole in the paper comes over a hole in the hollow bar air rushes in, and pa.s.sing through a tube actuates the type-setting machinery in a certain manner, so as to bring the desired die into contact with molten lead. The dies are, in the monotype, all carried in a magazine about three inches square, which moves backwards or forwards, to right or left, in obedience to orders from the perforated roll. The dies are arranged in exactly the same way as the keys on the keyboard. So that, supposing A to have been stamped on the roll, one of the perforations causes the magazine to slide one way, while the other shoves it another, until the combined motions bring the matrix engraved with the A underneath the small hole through which molten lead is forced. The letter is ejected and moves sideways through a narrow channel, pushing preceding letters before it, and the magazine is free for other movements.

At the end of each word a "s.p.a.ce" or blank lead is cast, its size exactly determined by the "justifying" hole belonging to that line.

Word follows word till the line is complete; then a knife-like lever rises, and the type is propelled into the "galley." Though a slave the casting machine will not tolerate injustice. Should the compositor have made a mistake, so that the line is too long or too short, automatic machinery at once comes into play, and slips the driving belt from the fixed to the loose pulley, thus stopping the machine till some one can attend to it. But if the punching has been correctly done, the machine will work away unattended till, a whole column of type having been set up, it comes to a standstill.

The advantages of the Monotype are easily seen. In order to save money a man need not possess the complete apparatus. If he has the keyboard only he becomes to a certain extent his own compositor, able to set up the type, as it were by proxy, at any convenient time. He can give his undivided attention to the keyboard, stop work whenever he likes without keeping a casting-machine idle, and as soon as his roll is complete forward it to a central establishment where type is set.

There a single man can superintend the completion of half-a-dozen men's labours at the keyboard. That means a great reduction of expense.

In due time he receives back his copy in the shape of set-up type, all ready to be corrected and transferred to the printing machines. The type done with, he can melt it down without fear of future regret, for he knows that the paper roll locked up in his cupboard will do its work a second time as well as it did the first. Should he need the same matter re-setting, he has only to send the roll through the post to the central establishment.

Thanks to Mr. Lanston's invention we may hope for the day when every parish will be able to do its own printing, or at least set up its own magazine. The only thing needful will be a monotype keyboard supplied by an enlightened Parish Council--as soon as the expense appears justifiable--and kept in the Post Office or Village Inst.i.tute. The payment of a small fee will ent.i.tle the Squire to punch out his speech on behalf of the Conservative Candidate, the Schoolmaster to compose special information for his pupils, the Rector to reduce to print pamphlets and appeals to charity. And if those of humbler degree think they can strike eloquence from the keys, they too will of course be allowed to turn out their ideas literally by the yard.

PHOTOGRAPHY IN COLOURS.

While photography was still in its infancy many people believed that, a means having been found of impressing the representation of an object on a sensitised surface, a short time only would have to elapse before the discovery of some method of registering the colours as well as the forms of nature.