_Indenting machines_:--The welt is known as that strip of leather around the shoe between the upper and the sole, and machines were invented for cutting and placing this, indenting it for the purpose of rendering it flexible and separating the st.i.tches, all a work until recently entirely done by hand. Machines for twining the seams in the uppers, and forming the scallops; machines especially adapted to the making of the heel, as heel tr.i.m.m.i.n.g and compressing, rounding and polishing, and for nailing the finished heel to the boot or shoe; machines for treating the sole in every way, rolling it, in place of the good old way of pounding it on a lap stone; tr.i.m.m.i.n.g, rounding, smoothing, and polishing it; machines for cutting out gores; machines for marking the uppers so that at one operation every shoe will be stamped by its size, number, name of manufacture, number of case, and any other convenient symbols; machines for setting the b.u.t.tons and eyelets; all these are simply members in the long line of inventions in this art.

The old style of boot has given way to the modern shoe and gaiter, but for the benefit of those who still wear them, special machines for shaping the leg, called boot trees, have been contrived.

So far had the art advanced that twenty years ago one workingman with much of this improved machinery combined in one machine called the "bootmaker," could make three hundred pairs of boots or shoes a day.

Upward of three thousand such machines were then at work throughout the world; and one hundred and fifty million pairs of boots were then being made annually thereon. Now the number of machines and pairs of boots and shoes has been quadrupled.

And the world is having its feet clothed far more extensively, better and at less cost than was ever possible by the hand system. The number of workers in the art, both men and women, has vastly increased instead of being diminished, while their wages have greatly advanced over the old rates.

As an ill.u.s.tration of how rapidly modern enterprise and invention proceeds in Yankeeland, it has been related that some years ago in Ma.s.sachusetts, after many of these shoe-making machines had got into use, a factory which was turning out 2400 pairs of shoes every day was completely destroyed by fire on a Wednesday night. On Thursday the manufacturer hired a neighbouring building and set carpenters at work fitting it up. On Friday he ordered a new and complete outfit of machinery from Boston; on Sat.u.r.day the machinery arrived and the men set it up; on Monday work was started, and on Tuesday the manufacturer was filling his orders to the full number of 2400 pairs a day.

There are very many people in the world who still prefer the hand-made shoe, and there is nothing to prevent the world generally from going back to that system if they choose; but St. Crispin's gentle art has blossomed into a vaster field of blessings for mankind under the fruitful impetus of invention than if left to vegetate under the simple processes of primitive man.

Horses, no less than man, have shared in the improvement in leather manufacture. The harnesses of the farmer's and labouring man's horses a century ago, when they were fortunate enough to own horses, were of the crudest description. Ropes, cords, coa.r.s.e bands of leather were the common provisions. Now the strength and cheapness of harnesses enable the poor man to equip his horse with a working suit impossible to have been produced a hundred years ago.

To the beautiful effects produced by the use of modern embossing machines on paper and wood have been added many charming patterns in _embossed_ leather. Books and leather cases, saddlery and household ornamentation of various descriptions have been either moulded into forms of beauty, or stamped or rolled by cameo and intaglio designs cut into the surface of fast-moving cylinders.

The leather manufactures have become so vastly important and valuable in some countries, especially in the United States--second, almost to agricultural products--that it would be very interesting to extend the description to many processes and machines, and to facts displaying the enormous traffic in leather, now necessarily omitted for want of s.p.a.ce.

CHAPTER XXIV.

MINERALS--WELLS.

Dost thou hear the hammer of Thor, Wielded in his gloves of iron?

As with leather, so with stone, the hand tools and hard labour have not changed in principle since the ancient days. The hammer for breaking, the lever for lifting, the saw for cutting, rubbing-stones and irons for smoothing and polishing, sand and water for the same purpose, the mallet and chisel, and other implements for ornamenting, the square, the level, and the plumb for their respective purposes, all are as old as the art of building.

And as for buildings and sculpture of stone and marble made by hand tools, we have yet to excel the pyramids, the Parthenon of Athens, which "Earth proudly wears as the best gem upon her zone," the palaces, coliseums, and aqueducts of Rome, the grand and polished tombs of India, the exquisite halls of the Alhambra, and the Gothic cathedrals.

But the time came when human blood and toil became too dear to be the possession solely of the rulers and the wealthy, and to be used alone to perpetuate and commemorate riches, power and glory.

Close on the expansion of men's minds came the expansion of steam and the development of modern inventions. The first application of the steam engine in fields of human labour was the drawing of water from the coal mines of England; then in drawing the coal itself.

It was only a step for the steam engine into a new field of labour when General Bentham introduced his system of wood-sawing machinery in 1800; and from sawing wood to sawing stone was only one more step. We find that taken in 1803 in Pennsylvania, when Oliver Evans of Philadelphia drove with a high-pressure steam engine, "twelve saws in heavy frames, sawing at the rate of one hundred feet of marble in twelve hours." How long would it have taken hand sawyers of marble at ancient Paros and Naxos to have done the same?

_Stone-cutting_ machines of other forms than sawing then followed.

It was desired to divide large blocks generally at the quarries to facilitate transportation. Machines for this purpose are called stone-channelling machines. They consist of a gang of chisels bound together and set on a framework which travels on a track adjacent to the stone to be cut, and so arranged that the cutters may be set to the stone at desired angles, moved automatically forward and back in the grooves they are cutting, be fed in or out, raised or lowered, detached, and otherwise manipulated in the operation.

Other stone-cutting machines had for their objects the cutting and moulding the edges of tables, mantels and slabs; and the cutting of circular and other curved work. In the later style of machine the cutter fixed on the end of a spindle is guided in the desired directions on the surface of the stone by a pointer, which, attached to the cutter spindle, moves in the grooves of a pattern also connected to the rotating support carrying the cutter.

Other forms of most ingenious stone-dressing and carving machines have been devised for cutting mouldings, and ornamental figures and devices, in accordance with a model or pattern fixed to the under side of the table which carries the stone or marble to be dressed; and in which, by means of a guide moving in the pattern, the diamond cutter or cutters, carried in a circular frame above the work and adjusted to its surface, are moved in the varying directions determined by the pattern. A stream of water is directed on the stone to clear it of the dust during the operations. The carving of stone by machinery is now a sister branch of wood carving. Monuments, ornamentation, and intricate forms of figures and characters are wrought with great accuracy by cutting and dressing tools guided by the patterns, or directed by the hand of the operator.

For the dressing of the faces of grindstones, special forms of cutting machines have been devised.

It was a slow and tedious task to drill holes through stone by hand tools; and it was indeed a revolution in this branch of the art when steam engines were employed to rotate a rod armed at its end with diamond or other cutters against the hardest stone. This mode of drilling also effected a revolution in the art of blasting. Then, neither height, nor depth, nor thickness of the stone could prevent the progress of the drill rod. Tunnels through mountain walls, and wells through solid quartz are cut to the depth of thousands of feet.

One instance is related of the wonderful efficiency on a smaller scale of such a machine: The immense columns of the State Capitol at Columbus, Ohio, were considered too heavy for the foundation on which they rested.

The American Diamond Rock Boring Company of Providence, Rhode Island, bored out a twenty-four inch core from each of the great pillars, and thus relieved the danger.

In the most economical and successful stone drills _compressed air_ is employed as the motive power to drive the drills, which may be used singly or in gangs, and which may be adjusted against the rock or quarry in any direction. When in position and ready for work a few moments will suffice to bore the holes, apply the explosive and blast the ledge. The cleaning away of submarine ledges in harbours, such as the great work at h.e.l.l Gate in the harbour of New York, has thus been effected.

_Crushing_:--Among the most useful inventions relating to stone working are machines for crushing stones and ores, and a.s.sorting them. The old way of hammering by hand was first succeeded by powerful stamp hammers worked by steam. Both methods of course are still followed, but they demand too great an expenditure of force and time.

About a third of a century ago, Eli Whitney Blake of New Haven, Connecticut, was a pioneer inventor of a new and most successful type of stone breaking machine, which ever since has been known as the "Blake Crusher." This crusher consists of two ponderous upright jaws, one fixed and the other movable, between which the stones or ores to be crushed are fed. Each of the jaws is lined with the hardest kind of chilled steel. The movable jaw is inclined from its lower end from the fixed jaw and at its upper end is pivoted to swing on a heavy round iron bar. The movable jaw is forced toward the fixed jaw by two opposite toggle levers set, in one form of the crusher, at their inner ends in steel bearings of a vertical vibrating, rocking lever, one of the toggles bearing at its outer end against the movable jaw and the outer toggle against a solid frame-work. The rocking lever is operated through a crank by a steam engine, and as it is vibrated, the toggle joint forces the lever end of the movable jaw towards the fixed jaw with immense force, breaking the hardest stone like an eggsh.e.l.l.

The setting of the movable jaw at an incline enables the large stone to be first cracked, the movable jaw then opens, and as the stone falls lower between the more contracted jaws, it is broken finer, until it is finally crushed or pulverized and falls through at the bottom. The movable jaw is adjustable and can be set to crush stones to a certain size.

As the rock drill made a revolution in blasting and tunnelling, so the Blake crusher revolutionised the art of road making. "Road metal," as the supply of broken stones for roads is now called, is the fruit of the crusher. Hundreds of tons of stone per day can be crushed to just the size desired, and the machine may be moved from place to place where most convenient to use.

Other crushers have been invented, formed on the principle of abrasion.

The stones, or ore, fall between two great revolving disks, having corrugated steel faces, which are set the desired distance apart, and between which the stones are crushed by the rubbing action. In this style of machine the principle of a gradual breaking from a coa.r.s.e to a finer grade, is maintained by setting the disks farther apart at the centre where the stone enters, and nearer together at their peripheries where the broken stone is discharged. Large smooth or corrugated rollers, conical disks, concentric rollers armed with teeth of varying sizes, and yet so arranged as to preserve the feature of the narrowing throat at the bottom or place of discharge, have also been devised and extensively used.

A long line of inventions has appeared especially adapted to break up and separate coal into different sizes. To view the various monstrous heaps of a.s.sorted coals at the mouth of a coal mine creates an impression that some great witch had imposed on a poor victim the gigantic and seemingly impossible task of breaking and a.s.sorting a vast heap of coal into these separate piles within a certain time--a task which also seems to have been miraculously and successfully performed within such an exceedingly short time as to either satisfy or confuse the presiding evil genius.

Modern civilisation has been developed mostly from steam and coal, and they have been to each other as strong brothers, growing more and more mutually dependent to meet the demands made upon them.

The mining of coal, and its subsequent treatment for burning, before the invention of the steam engine, were long, painful, and laborious tasks, and the steam engine could never have had its modern wants supplied if its power had not been used to supplement, with a hundredfold increased effect, the labour of human hands.

It being impracticable to carry steam or the steam engine to the bottom of the mine for work there, compressed air is there employed, which is compressed by a steam engine up at the mouth. By this compressed air operated in a cylinder to drive a piston, and a connecting rod and a pick, a ma.s.sive steel pick attached to the rod may be driven in any direction against the wall of coal at the rate of from ninety to one hundred and twenty blows per minute; and at the same time the discharged compressed, cold, pure, fresh air flows into and through the mine, affording ventilation when and where most needed.

In addition to these great drills, more recent inventors have brought out small machines for single operators, worked by the electric motor.

After the coal is lifted out, broken and a.s.sorted, it needs to be washed free of the adhering dust and dirt; and for this purpose machines are provided, as well as for screening, loading and weighing. The operations of breaking, a.s.sorting and washing are often combined in one machine, while an intermediate hand process for separating the pieces of slate from the coal may be employed; but additional automatic means for separating the coal and slate are provided, consisting in forcing with great power water through the coal as it falls into a chamber, which carries the lighter slate to the top of the chamber, where it is at once drawn off.

The chief of machines with _ores_ is the _ore mill_, which not only breaks up the ore but grinds or pulverises it.

Some chemical and other processes for reducing ores have been referred to in the Chapter on Metallurgy.

Other mechanical processes consist of _separators_ of various descriptions--a prominent one of which acts on the princ.i.p.al of centrifugal force. The crushed material from a spout being led to the centre of a rapidly rotating disk is thrown off by centrifugal force; and as the lighter portions are thrown farther from the disk, and the heavier portions nearer to the same, the material is automatically a.s.sorted as to size and weight. As the disk revolves these a.s.sorted portions fall through properly graded apertures into separate channels of a circular trough, from whence they are swept out by brushes secured to a support revolving with the disk.

Many forms of ore washing machines have been invented to treat the ore after it has been reduced to powder. These are known by various names, as jiggers, rifflers, concentrators, washing frames, etc. A stream of water is directed on, into, and through the ma.s.s of pulverised ore and dirt, the dirt and kindred materials, lighter than the ore, are raised and floated towards the top of the receptacle and carried away, while the ore settles.

This operation is frequently carried on in connection with amalgamated surfaces over which the metal is pa.s.sed to still further attract and concentrate the ore. An endless ap.r.o.n travelling over cylinders is sometimes employed, composed of slats the surface of each of which is coated with an amalgam, and on this belt the powdered ore is spread thinly and carried forward. The vibrations of the belt tend to shake and distribute the ore particles, the amalgam attracts them, the refuse is thrown off as the belt pa.s.ses down over the cylinder, while the ore particles are retained and brushed off into a proper receptacle.

_Amalgamators_ themselves form a large cla.s.s of inventions. They are known as electric, lead, mercury, plate, vacuum, vapour, etc.

By the help of these and a vast number of other kindred inventions, the business of mining in all its branches has been revolutionised and transformed, even within the last half century. With the vast increase in the output of coal, and of ores, and the incalculable saving of hand labour, the number of operators has been increased in the same proportion, their wages increased, their hours of labour shortened, and their comforts multiplied in variety and quant.i.ty, with a diminished cost. The whole business of mining has been raised from ceaseless darkness and drudgery to light and dignity. Opportunity has been created for miners to become men of standing in the community in which they live; and means provided for educating their children and for obtaining comfortable homes adorned with the refinements of civilisation.

_Well boring_ is an ancient art--known to the Egyptians and the Chinese.

Wells were coeval with Abraham when his servant had the celebrated interview with Rebecca. "Jacob's well at Sychar--the ancient Shechim--has been visited by travellers in all ages and has been minutely described. It is nine feet in diameter and one hundred and five feet deep, made entirely through rock. When visited by Maundrel it contained fifteen feet of water."--_Knight._ Some kind of a drill must have been used to have cut so great a depth through rock. The Chinese method of boring wells from time immemorial has been by the use of a sharp chisel-like piece of hard iron on the end of a heavy iron and wood frame weighing four or five hundred pounds, lifted by a lever and turned by a rattan cord operated by hand, and by which wells from fifteen hundred to eighteen hundred feet in depth and five or six inches in diameter have been bored.

This method has lately been improved by attaching the chisel part, which is made very heavy, to a rope of peculiar manufacture, which gives the chisel a turn as it strikes, combined with an air pump to suck up from the hole the acc.u.mulating dirt and water.

Artesian wells appear to have first been known in Europe in the province of Artois, France, in the thirteenth century. Hence their name. The previous state of the art in Egypt, China and elsewhere was not then known.

Other modern inventions in well-making machinery have consisted in innumerable devices to supplant manual labour and to meet new conditions.