Inventions in the Century Part 8

Inventions for the excavating of clay, piling and burning it in a crude state for ballast for railways, are important, especially for those railways which traverse areas where clay is plentiful, and stones and gravel are lacking.

Sinking shafts through quicksands by artificially freezing the sand, so as to form a firm frozen wall immediately around the area where the shaft is to be sunk, is a recent new idea.

Modern countries especially are waking up to the necessity of good roads, not only as a necessary means of transportation, but as a pre-requisite to decent civilisation in all respects. And, therefore, great activity has been had in the last third of a century in invention of machines for finis.h.i.+ng and repairing roads.

In the matter of sewer construction, regarded now so necessary in all civilised cities and thickly-settled communities as one of the means of proper sanitation, great improvements have been made in deep sewerage, in which the work is largely performed below the surface and with little obstruction to street traffic.

In connection with excavating and dredging machines, mention should be made of those great works in the construction of which they bore such important parts, as drainage and land reclamation, such as is seen in the modern extensions of land reclamation in Holland, in the Haarlem lake district in the North part of England, the swamps of Florida and the drainage of the London district; in modern tunnels such as the Hoosac in America and the three great ones through the Alps: the Mont Cenis, St. Gothard, and Arlberg, the work in which developed an entirely new system of engineering, by the application of newly-discovered explosives for blasting, new rock-drilling machinery, new air-compressing machines for driving the drill machines and ventilating the works, and new hydraulic and pumping machinery for sinking shafts and pumping out the water.

The great ca.n.a.ls, especially the Suez, developed a new system of ca.n.a.l engineering. Thus by modern inventions of devices for digging and blasting, dredging and draining and attendant operations, some of the greatest works of man on earth have been produced, and evinced the exercise of his highest inventive genius.

If one wishes an ocular demonstration of the wonders wrought in the 19th century in the several domains of engineering, let him take a Pullman train across the continent from New York to San Francisco. The distance is 3,000 miles and the time is four days and four nights. The car in which the pa.s.senger finds himself is a marvel of woodwork and upholstery--a description of the machinery and processes for producing which belongs to other arts. The railroad tracks upon which the vehicle moves are in themselves the results of many inventions. There is the width of the track, and it was only after a long and expensive contest that countries and corporations settled upon a uniform gauge. The common gauge of the leading countries and roads is now 4 feet 8 inches. A greater width is known as a broad gauge, a less width as a narrow gauge.

Then as to the rail: first the wooden, then the iron and now the steel, and all of many shapes and weights. The T-rail invented by Birkensaw in 1820, having two f.l.a.n.g.es at the top to form a wide berth for the wheels of the rolling stock, the vertical portion gripped by chairs which are spiked to the ties, is the best known. Then the frogs, a V-shaped device by which the wheels are guided from one line of rails to another, when they form angles with each other; the car wheel made with a f.l.a.n.g.e or f.l.a.n.g.es to fit the rail, and the railway gates, ingenious contrivances that guard railway crossings and are operated automatically by the pa.s.sing trains, but more commonly by watchmen. The car may be lighted with electricity, and as the train dashes along at the rate of 30 to 80 miles an hour, it may be stopped in less than a minute by the touch of the engineer on an air brake. Is it midwinter and are mountains of snow encountered? They disappear before the railway snow-plough more quickly than they came. It pa.s.ses over bridges, through tunnels, across viaducts, around the edges of mountain peaks, every mile revealing the wondrous work of man's inventive genius for encompa.s.sing the earth with speed, safety and comfort. Over one-half million miles of these railway tracks are on the earth's surface to-day!

Not only has the railway superseded horse power in the matter of transportation to a vast extent, but other modes of transportation are taking the place of that useful animal. The old-fas.h.i.+oned stage coach, and then the omnibus, were successively succeeded by the street car drawn by horses, and then about twenty years ago the horse began to be withdrawn from that work and the cable subst.i.tuted.

_Cable transportation_ developed from the art of making iron wire and steel wire ropes or cables. And endless cables placed underground, conveyed over rollers and supported on suitable yokes, and driven from a great central power house, came into use, and to which the cars were connected by ingeniously contrived lever grips--operated by the driver on the car. These great cable constructions, expensive as they were, were found more economical than horse power. In fact, there is no modernly discovered practical motive power but what has been found less expensive both as to time and money than horse power. But the cable for this purpose is now in turn everywhere yielding to electricity, the great motor next to steam. The overhead cable system for the transportation of materials of various descriptions in carriers, also run by a central motor, is still very extensively used. The cable plan has also been tried with some success in the propelling of ca.n.a.l boats.

_Ca.n.a.ls_, themselves, although finding a most serious and in some localities an entirely destructive rival in the railroad, have grown in size and importance, and in appliances that have been subst.i.tuted for the old-style locks. The latest form of this device is what is known as the pneumatic balance lock system.

It has been said by Octave Chanute that "Progress in civilisation may fairly be said to be dependent upon the facilities for men to get about, upon their intercourse with other men and nations, not only in order to supply their mutual needs cheaply, but to learn from each other their wants, their discoveries and their inventions." Next to the power and means for moving people, come the immense and wonderful inventions for lifting and loading, such as cranes and derricks, means for coaling s.h.i.+ps and steamers, for handling and storing the great agricultural products, grain and hay, and that modern wonder, the _grain elevator_, that dots the coasts of rivers, lakes and seas, receives the vast stores of golden grain from thousands of steam cars that come to it laden from distant plains and discharges it swiftly in mountain loads into vessels and steamers to be carried to the mult.i.tudes across the seas, and to satisfy that ever-continuing cry, "Give us this day our daily bread."

CHAPTER IX.

ELECTRICITY.

In 1900 the real nature of electricity appears to be as unknown as it was in 1800.

Franklin in the eighteenth century defined electricity as consisting of particles of matter incomparably more subtle than air, and which pervaded all bodies. At the close of the nineteenth century electricity defined as "simply a form of energy which imparts to material substances a peculiar state or condition, and that all such substances partake more or less of this condition."

These theories and the late discovery of Hertz that electrical energy manifests itself in the form of waves, oscillations or vibrations, similar to light, but not so rapid as the vibrations of light, const.i.tute about all that is known about the nature of this force.

Franklin believed it was a single fluid, but others taught that there were two kinds of electricity, positive and negative, that the like kinds were repulsive and the unlike kinds attractive, and that when generated it flowed in currents.

Such terms are not now regarded as representing actual varieties of this force, but are retained as convenient modes of expression, for want of better ones, as expressing the conditions or states of electricity when produced.

Electricity produced by friction, that is, developed upon the surface of a body by rubbing it with a dissimilar body, and called frictional or static electricity, was the only kind produced artificially in the days of Franklin. What is known as galvanism, or animal electricity, also takes its date in the 18th century, to which further reference will be made. Since 1799 there have been discovered additional sources, among which are voltaic electricity, or electricity produced by chemical action, such as is manifested when two dissimilar metals are brought near each other or together, and electrical manifestations produced by a decomposing action, one upon the other through a suitable medium; inductive electricity, or electricity developed or induced in one body by its proximity to another body through which a current is flowing; magnetic electricity, the conversion of the power of a magnet into electric force, and the reverse of this, the production of magnetic force by a current of electricity; and thermal electricity, or that generated by heat. Electricity developed by these, or other means in contra-distinction to that produced by friction, has been called dynamic; but all electric force is now regarded as dynamic, in the sense that forces are always in motion and never at rest.

Many of the manifestations and experiments in later day fields which, by reason of their production by different means, have been given the names of discovery and invention, had become known to Franklin and others, by means of the old methods in frictional electricity. They are all, however, but different routes leading to the same goal. In the midst of the brilliant discoveries of modern times confronting us on every side we should not forget the honourable efforts of the fathers of the science.

We need not dwell on what the ancients produced in this line. It was a single fact only:--The Greeks discovered that amber, a resinous substance, when rubbed would attract lighter bodies to it.

In 1600 appeared the father of modern electricity--Dr. Gilbert of Colchester, physician to Queen Elizabeth. He revived the one experiment of antiquity, and added to it the further fact that many substances besides amber, when rubbed, would manifest the same electric condition, such as sulphur, sapphire, wax, gla.s.s and other bodies. And thus he opened the field of electrodes. He was the first to use the terms, electricity, electric and electrode, which he derived from the word _elektron_, the Greek name for amber. He observed the actions of magnets, and conjectured the fundamental ident.i.ty of magnetism and electricity. He arranged an electrometer, consisting of an iron needle poised on a pivot, by which to note the action of the magnet. This was about the time that Otto von Guericke of Magdeburg, Germany, was born.

He became a "natural" philosopher, and for thirty-five years was burgomaster of his native town. He invented the air-pump, and he it was who ill.u.s.trated the force of atmospheric pressure by fitting together two hollow bra.s.s hemispheres which, after the air within them had been exhausted, could not be pulled apart. He also invented a barometer, and as an astronomer suggested that the return of comets might be calculated. He invented and constructed the first machine for generating electricity. It consisted of a ball of sulphur rotated on an axis, and which was electrified by friction of the hand, the ball receiving negative electricity while the positive flowed through the person to the earth. With this machine "he heard the first sound and saw the first light in artificially excited electricity." The machine was improved by Sir Isaac Newton and others, and before the close of that century was put into substantially its present form of a round gla.s.s plate rotated between insulated leather cus.h.i.+ons coated with an amalgam of tin and zinc, the positive or vitreous electricity thus developed being acc.u.mulated on two large hollow bra.s.s cylinders with globular ends, supported on gla.s.s pillars. Gray in 1729 discovered the conductive power of certain substances, and that the electrical influence could be conveyed to a distance by means of an insulated wire. This was the first step towards the electric telegraph.

Dufay, the French philosopher and author, who in 1733-1737 wrote the _Memoirs of the French Academy_, was, it seems, the first to observe electrical attractions and repulsions; that electrified resinous substances repelled like substances while they attracted bodies electrified by contact with gla.s.s; and he, therefore, to the latter applied the term _vitreous_ electricity and to the former the term _resinous_ electricity. In 1745 Prof. Muschenbroeck of Leyden University developed the celebrated Leyden jar. This is a gla.s.s jar coated both inside and outside with tinfoil for about four-fifths of its height. Its mouth is closed with a cork through which is pa.s.sed a metallic rod, terminating above in a k.n.o.b and connected below with the inner coating by a chain or a piece of tinfoil. If the inner coating be connected with an electrical machine and the outer coating with the earth, a current of electricity is established, and the inner coating receives what is called a positive and the outer coating a negative charge. On connecting the two surfaces by means of a metallic discharger having a non-conducting handle a spark is obtained. Thus the Leyden jar is both a collector and a condenser of electricity. On arranging a series of such jars and joining their outer and inner surfaces, and connecting the series with an electrical machine, a battery is obtained of greater or less power according to the number of jars employed and the extent of supply from the machine.

The principle of the Leyden jar was discovered by accident. Cuneus, a pupil of Muschenbroeck, was one day trying to charge some water in a gla.s.s bottle with electricity by connecting it with a chain to the sparking k.n.o.b of an electrical machine. Holding the bottle in one hand he arranged the chain with the other, and received a violent shock. His teacher then tried the experiment himself, with a still livelier and more convincing result, whereupon he declared that he would not repeat the trial for the whole Kingdom of France.

When the science of static electricity was thus far developed, with a machine for generating it and a collector to receive it, many experiments followed. Charles Morrison in 1753, in the _Scots Magazine_, proposed a telegraph system of insulated wires with a corresponding number of characters to be signalled between two stations. Other schemes were proposed at different times down to the close of the century.

Franklin records among several other experiments with frictional electricity acc.u.mulated by the Leyden jar battery the following results, produced chiefly by himself: The existence of an attractive and a repulsive action of electricity; the restoration of the equilibrium of electrical force between electrified and non-electrified bodies, or between bodies differently supplied with the force; the electroscope, a body charged with electricity and used to indicate the presence and condition of electricity in another body; the production of work, as the turning of wheels, by which it was proposed a spit for roasting meat might be formed, and the ringing of chimes by a wheel, which was done; the firing of gunpowder, the firing of wood, resin and spirits; the drawing off a charge from electrified bodies at a near distance by pointed rods; the heating and melting of metals; the production of light; the magnetising of needles and of bars of iron, giving rise to the a.n.a.logy of magnetism and electricity.

Franklin, who had gone thus far, and who also had drawn the lightning from the clouds, identified it as electricity, and taught the mode of its subjection, felt chagrined that more had not been done with this subtle agent in the service of man. He believed, however, that the day-spring of science was opening, and he seemed to have caught some reflection of its coming light. Observing the return to life and activity of some flies long imprisoned in a bottle of Madeira wine and which he restored by exposure to the sun and air, he wrote that he should like to be immersed at death with a few friends in a cask of Madeira, to be recalled to life a hundred years thence to observe the state of his country. It would not have been necessary for him to have been embalmed that length of time to have witnessed some great developments of his favorite science. He died in 1790, and it has been said that there was more real progress in this science in the first decade of the nineteenth century than in all previous centuries put together.

Before opening the door of the 19th century, let us glance at one more experiment in the 18th:

While the aged Franklin was dying, Dr Luigi Galvani of Bologna, an Italian physician, medical lecturer, and learned author, was preparing for publication his celebrated work, _De viribus Electricitatis in Motu Musculari Commentarius_, in which he described his discovery made a few years before of the action of the electric current on the legs and spinal column of a frog hung on a copper nail. This discovery at once excited the attention of scientists, but in the absence of any immediate practical results the mult.i.tude dubbed him the "frog philosopher." He proceeded with his experiments on animals and animal matter, and developed the doctrine and theories of what is known as animal or galvanic electricity. His fellow countryman and contemporary, Prof.

Volta of Pavia, took decided issue with Galvani and maintained that the pretended animal electricity was nothing but electricity developed by the contact of two different metals. Subsequent investigations and discoveries have established the fact that both theories have truth for their basis, and that electricity is developed both by muscular and nervous energy as well as by chemical action. In 1799 Volta invented his celebrated pile, consisting of alternate disks of copper and zinc separated by a cloth moistened with a dilute acid; and soon after an arrangement of cups--each containing a dilute acid and a copper and a zinc plate placed a little distance apart, and thus dispensing with the cloth. In both instances he connected the end plate of one kind with the opposite end plate of the other kind by a wire, and in both arrangements produced a current of electricity. To the discoveries, experiments, and disputes of Galvani and Volta and to those of their respective adherents, the way was opened to the splendid electrical inventions of the century, and the discovery of a new world of light, heat, speech and power. The discoveries of Galvani and Volta at once set leading scientists at work. Fabroni of Florence, and Sir Humphry Davy and Wollaston of England, commenced interesting experiments, showing that rapid oxidation and chemical decomposition of the metals took place in the voltaic pile.

By the discoveries of Galvani the physicians and physiologists were greatly excited, and believed that by this new vital power the nature of all kinds of nervous diseases could be explored and the remedy applied.

Volta's discovery excited the chemists. If two dissimilar metals could be decomposed and power at the same time produced they contended that practical work might be done with the force. In 1800 Nicholson and Carlisle decomposed water by pa.s.sing the electric current through the same; Ritter decomposed copper sulphate, and Davy decomposed the alkalies, potash and soda. Thus the art of electrolysis--the decomposition of substances by the galvanic current, was established.

Later Faraday laid down its laws. Naturally inventions sprung up in new forms of batteries. The pile and cup battery of Volta had been succeeded by the trough battery--a long box filled with separated plates set in dilute acid. The trough battery was used by Sir Humphry Davy in his series of great experiments--1806-1808--in which he isolated the metallic bases, calcium, sodium, pota.s.sium, etc. It consisted of 2000 double plates of copper and zinc, each having a surface of 32 square inches. With this same trough battery Davy in 1812 produced the first electric carbon light, the bright herald of later glories.

Among the most noted new batteries were Daniell's, Grove's and Bunsen's.

They are called the "two fluid batteries," because in place of a single acidulated bath in which the dissimilar metals were before placed, two different liquid solutions were employed.

John Frederick Daniell of London, noted for his great work, _Meteorological Essays_, and other scientific publications, and as Professor of Chemistry in King's College, in 1836, described how a powerful and constant current of electricity may be continued for an unlimited period by a battery composed of zinc standing in an acid solution and a sheet of copper in a solution of sulphate of copper.

Sir William Robert Grove, first an English physician, then an eminent lawyer, and then a professor of natural philosophy, and the first to announce the great theory of the Correlation of Physical Forces, in 1839 produced his battery, much more powerful than any previous one, and still in general use. In it zinc and platinum are the metals used--the zinc bent into cylindrical form and placed in a gla.s.s jar containing a weak solution of sulphuric acid, while the platinum stands in a porous jar holding strong nitric acid and surrounded by the zinc. Among the electrical discoveries of Grove were the decomposition by electricity of water into free oxygen and hydrogen, the electricity of the flame of the blow-pipe, electrical action produced by proximity, without contact, of dissimilar metals, molecular movements induced in metals by the electric current, and the conversion of electricity into mechanical force.

Robert Wilhelm Bunsen, a German chemist and philosopher and scientific writer, who invented some of the most important aids to scientific research of the century, who constructed the best working chemical laboratory on the continent and founded the most celebrated schools of chemistry in Europe, invented a battery, sometimes called the carbon battery, in which the expensive pole of platinum in the Grove battery is replaced by one of carbon. It was found that this combination gave a greater current than that of zinc and platinum.

A great variety of useful voltaic batteries have since been devised by others, too numerous to be mentioned here. There is another form of battery having for its object the storing of energy by electrolysis, and liberating it when desired, in the form of an electric current, and known as an acc.u.mulator, or secondary, polarization, or storage battery.

Prof. Ritter had noticed that the two plates of metal which furnished the electric current, when placed in the acid liquid and united, could in themselves furnish a current, and the inventing of _storage_ batteries was thus produced. The princ.i.p.al ones of this cla.s.s are Gustave Plante's of 1860 and M. Camille Faure's of 1880. These have still further been improved. Still another form are the _thermo-electric batteries_, in which the electro-motive force is produced by the joining of two different metals, connecting them by a wire and heating their junctions. Thus, an electric current is obtained directly from heat, without going through the intermediate processes of boiling water to produce steam, using this steam to drive an engine, and using this engine to turn a dynamo machine to produce power.

But let us retrace our steps:--As previously stated, Franklin had experimented with frictional electricity on needles, and had magnetised and polarised them and noticed their deflection; and Lesage had established an experimental telegraph at Geneva by the same kind of electricity more than a hundred years ago. But frictional electricity could not be transmitted with power over long distances, and was for practical purposes uncontrollable by reason of its great diffusion over surfaces, while voltaic electricity was found to be more intense and could be developed with great power along a wire for any distance. Fine wires had been heated and even melted by Franklin by frictional electricity, and now Ritter, Pfaff and others observed the same effect produced on the conducting wires by a voltaic current; and Curtet, on closing the pa.s.sage with a piece of charcoal, produced a brilliant light, which was followed by Davy's light already mentioned.

As early as 1802 an Italian savant, Gian D. Romagnosi of Trent, learning of Volta's discovery, observed and announced in a public print the deflection of the magnetic needle when placed near a parallel conductor of the galvanic current. In the years 1819 and 1820 so many brilliant discoveries and inventions were made by eminent men, independently and together, and at such near and distant places, that it is hard telling who and which was first. It was in 1819 that the celebrated Danish physicist, Oersted of Copenhagen, rediscovered the phenomena that the voltaic current would deflect a magnetic needle, and that the needle would turn at right angles to the wire. In 1820 Prof. S. C. Schweigger of Halle discovered that this deflecting force was increased when the wire was wound several times round the needle, and thus he invented the magnetising helix. He also then invented a galvano-magnetic indicator (a single-wire circuit) by giving the insulated wire a number of turns around an elongated frame longitudinally enclosing the compa.s.s needle, thus multiplying the effect of the current upon the sensitive needle, and converting it into a practical _measuring_ instrument--known as the galvanometer, and used to observe the strength of currents. In the same year Arago found that iron filings were attracted by a voltaic charged wire; and Arago and Davy that a piece of soft iron surrounded spirally by a wire through which such a current was pa.s.sed would become magnetic, attract to it other metals while in that condition, immediately drop them the instant the current ceased, and that such current would permanently magnetise a steel bar. The elements of the _electro-magnet_ had thus been produced. It was in that year that Ampere discovered that magnetism is the circulation of currents of electricity at right angles to the axis of the needle or bar joining the two poles of the magnet. He then laid down the laws of interaction between magnets and electrical currents, and in this same year he proposed an electric-magneto telegraph consisting of the combination of a voltaic battery, conducting wires, and magnetic needles, one needle for each letter of the alphabet.

The discoveries of Ampere as to the laws of electricity have been likened to the discovery of Newton of the law of gravitation.

Still no practical result, that is, no useful machine, had been produced by the electro-magnet.

In 1825 Sturgeon of England bent a piece of wire into the shape of a horse-shoe, insulated it with a coating of sealing wax, wound a fine copper wire around it, thus making a helix, pa.s.sed a galvanic current through the helix, and thus invented the first practical electro-magnet.

But Sturgeon's magnet was weak, and could not transmit power for more than fifty feet. Already, however, it had been urged that Sturgeon's magnet could be used for telegraphic purposes, and a futile trial was made. In the field during this decade also labored the German professors Gauss and Weber, and Baron Schilling of Russia. In 1829 Prof. Barlow of England published an article in which he summarised what had been done, and scientifically demonstrated to his own satisfaction that an electro-magnetic telegraph was impracticable, and his conclusion was accepted by the scientific world as a fact. This was, however, not the first nor the last time that scientific men had predicted impracticabilities with electricity which afterwards blossomed into full success. But even before Prof. Barlow was thus arriving at his discouraging conclusion, Prof. Joseph Henry at the Albany Inst.i.tute in the State of New York had commenced experiments which resulted in the complete and successful demonstration of the power of electro-magnetism for not only telegraph purposes but for almost every advancement that has since been had in this branch of physics. In March 1829 he exhibited at his Inst.i.tute the magnetic "spool" or "bobbin," that form of coil composed of tightly-wound, silk-covered wire which he had constructed, and which since has been universally employed for nearly every application of electro-magnetism, of induction, or of magneto-electrics.

And in the same year and in 1830 he produced those powerful magnets through which the energy of a galvanic battery was used to lift hundreds of tons of weight.

In view of all the facts now historically established, there can be no doubt that previous to Henry's experiments the means for developing magnetism in soft iron were imperfectly understood, and that, as found by Prof. Barlow, the electro-magnet which then existed was inapplicable and impracticable for the transmission of power to a distance. Prof.

Henry was the first to prove that a galvanic battery of "intensity" must be employed to project the current through a long conductor, and that a magnet of one long wire must be used to receive this current; the first to magnetise a piece of soft iron at a distance and call attention to its applicability to the telegraph; the first to actually sound a bell at a distance by means of the electro-magnet; and the first to show that the principles he developed were applicable and necessary to the practical operation of an effective telegraph system.

Sturgeon, the parent of the electro-magnet, on learning of Henry's discoveries and inventions, wrote: "Professor Henry has been enabled to produce a magnetic force which totally eclipses every other in the whole annals of magnetism; and no parallel is to be found since the miraculous suspension of the celebrated oriental impostor in his iron coffin."

(_Philosophical Magazine and Annals_, 1832.)

The third decade was now prepared for the development of the telegraph.