the year 1847 marked a period of great territorial acquisition by the american people, with incalculable additions to their actual and potential wealth. by the rational compromise with england in the dispute over the oregon region, president polk had secured during 1846, for undisturbed settlement, three hundred thousand square miles of forest, fertile land, and fisheries, including the whole fair columbia valley. our active "policy of the pacific" dated from that hour. with swift and clinching succession came the melodramatic mexican war, and february, 1848, saw another vast territory south of oregon and west of the rocky mountains added by treaty to the united states. thus in about eighteen months there had been pieced into the national domain for quick development and exploitation a region as large as the entire union of thirteen states at the close of the war of independence. moreover, within its boundaries was embraced all the great american gold-field, just on the eve of discovery, for marshall had detected the shining particles in the mill-race at the foot of the sierra nevada nine days before mexico signed away her rights in california and in all the vague, remote hinterland facing cathayward.

equally momentous were the times in europe, where the attempt to secure opportunities of expansion as well as larger liberty for the individual took quite different form. the old absolutist system of government was fast breaking up, and ancient thrones were tottering. the red lava of deep revolutionary fires oozed up through many glowing cracks in the political crust, and all the social strata were shaken. that the wild outbursts of insurrection midway in the fifth decade failed and died away was not surprising, for the superincumbent deposits of tradition and convention were thick. but the retrospect indicates that many reforms and political changes were accomplished, although the process involved the exile of not a few ardent spirits to america, to become leading statesmen, inventors, journalists, and financiers. in 1847, too, russia began her tremendous march eastward into central asia, just as france was solidifying her first gains on the littoral of northern africa. in england the fierce fervor of the chartist movement, with its violent rhetoric as to the rights of man, was sobering down and passing pervasively into numerous practical schemes for social and political amelioration, constituting in their entirety a most profound change throughout every part of the national life.

into such times thomas alva edison was born, and his relations to them and to the events of the past sixty years are the subject of this narrative. aside from the personal interest that attaches to the picturesque career, so typically american, there is a broader aspect in which the work of the "franklin of the nineteenth century" touches the welfare and progress of the race. it is difficult at any time to determine the effect of any single invention, and the investigation becomes more difficult where inventions of the first class have been crowded upon each other in rapid and bewildering succession. but it will be admitted that in edison one deals with a central figure of the great age that saw the invention and introduction in practical form of the telegraph, the submarine cable, the telephone, the electric light, the electric railway, the electric trolley-car, the storage battery, the electric motor, the phonograph, the wireless telegraph; and that the influence of these on the world's affairs has not been excelled at any time by that of any other corresponding advances in the arts and sciences. these pages deal with edison's share in the great work of the last half century in abridging distance, communicating intelligence, lessening toil, improving illumination, recording forever the human voice; and on behalf of inventive genius it may be urged that its beneficent results and gifts to mankind compare with any to be credited to statesman, warrior, or creative writer of the same period.

viewed from the standpoint of inventive progress, the first half of the nineteenth century had passed very profitably when edison appeared—every year marked by some notable achievement in the arts and sciences, with promise of its early and abundant fruition in commerce and industry. there had been exactly four decades of steam navigation on american waters. railways were growing at the rate of nearly one thousand miles annually. gas had become familiar as a means of illumination in large cities. looms and tools and printing-presses were everywhere being liberated from the slow toil of man-power. the first photographs had been taken. chloroform, nitrous oxide gas, and ether had been placed at the service of the physician in saving life, and the revolver, guncotton, and nitroglycerine added to the agencies for slaughter. new metals, chemicals, and elements had become available in large numbers, gases had been liquefied and solidified, and the range of useful heat and cold indefinitely extended. the safety-lamp had been given to the miner, the caisson to the bridge-builder, the anti-friction metal to the mechanic for bearings. it was already known how to vulcanize rubber, and how to galvanize iron. the application of machinery in the harvest-field had begun with the embryonic reaper, while both the bicycle and the automobile were heralded in primitive prototypes. the gigantic expansion of the iron and steel industry was foreshadowed in the change from wood to coal in the smelting furnaces. the sewing-machine had brought with it, like the friction match, one of the most profound influences in modifying domestic life, and making it different from that of all preceding time.

even in 1847 few of these things had lost their novelty, most of them were in the earlier stages of development. but it is when we turn to electricity that the rich virgin condition of an illimitable new kingdom of discovery is seen. perhaps the word "utilization" or "application" is better than discovery, for then, as now, an endless wealth of phenomena noted by experimenters from gilbert to franklin and faraday awaited the invention that could alone render them useful to mankind. the eighteenth century, keenly curious and ceaselessly active in this fascinating field of investigation, had not, after all, left much of a legacy in either principles or appliances. the lodestone and the compass; the frictional machine; the leyden jar; the nature of conductors and insulators; the identity of electricity and the thunder-storm flash; the use of lightning-rods; the physiological effects of an electrical shock—these constituted the bulk of the bequest to which philosophers were the only heirs. pregnant with possibilities were many of the observations that had been recorded. but these few appliances made up the meagre kit of tools with which the nineteenth century entered upon its task of acquiring the arts and conveniences now such an intimate part of "human nature's daily food" that the average american to-day pays more for his electrical service than he does for bread.

with the first year of the new century came volta's invention of the chemical battery as a means of producing electricity. a well-known italian picture represents volta exhibiting his apparatus before the young conqueror napoleon, then ravishing from the peninsula its treasure of ancient art and founding an ephemeral empire. at such a moment this gift of despoiled italy to the world was a noble revenge, setting in motion incalculable beneficent forces and agencies. for the first time man had command of a steady supply of electricity without toil or effort. the useful results obtainable previously from the current of a frictional machine were not much greater than those to be derived from the flight of a rocket. while the frictional appliance is still employed in medicine, it ranks with the flint axe and the tinder-box in industrial obsolescence. no art or trade could be founded on it; no diminution of daily work or increase of daily comfort could be secured with it. but the little battery with its metal plates in a weak solution proved a perennial reservoir of electrical energy, safe and controllable, from which supplies could be drawn at will. that which was wild had become domesticated; regular crops took the place of haphazard gleanings from brake or prairie; the possibility of electrical starvation was forever left behind.

immediately new processes of inestimable value revealed themselves; new methods were suggested. almost all the electrical arts now employed made their beginnings in the next twenty-five years, and while the more extensive of them depend to-day on the dynamo for electrical energy, some of the most important still remain in loyal allegiance to the older source. the battery itself soon underwent modifications, and new types were evolved—the storage, the double-fluid, and the dry. various analogies next pointed to the use of heat, and the thermoelectric cell emerged, embodying the application of flame to the junction of two different metals. davy, of the safety-lamp, threw a volume of current across the gap between two sticks of charcoal, and the voltaic arc, forerunner of electric lighting, shed its bright beams upon a dazzled world. the decomposition of water by electrolytic action was recognized and made the basis of communicating at a distance even before the days of the electromagnet. the ties that bind electricity and magnetism in twinship of relation and interaction were detected, and faraday's work in induction gave the world at once the dynamo and the motor. "hitch your wagon to a star," said emerson. to all the coal-fields and all the waterfalls faraday had directly hitched the wheels of industry. not only was it now possible to convert mechanical energy into electricity cheaply and in illimitable quantities, but electricity at once showed its ubiquitous availability as a motive power. boats were propelled by it, cars were hauled, and even papers printed. electroplating became an art, and telegraphy sprang into active being on both sides of the atlantic.

at the time edison was born, in 1847, telegraphy, upon which he was to leave so indelible an imprint, had barely struggled into acceptance by the public. in england, wheatstone and cooke had introduced a ponderous magnetic needle telegraph. in america, in 1840, morse had taken out his first patent on an electromagnetic telegraph, the principle of which is dominating in the art to this day. four years later the memorable message "what hath god wrought!" was sent by young miss ellsworth over his circuits, and incredulous washington was advised by wire of the action of the democratic convention in baltimore in nominating polk. by 1847 circuits had been strung between washington and new york, under private enterprise, the government having declined to buy the morse system for $100,000. everything was crude and primitive. the poles were two hundred feet apart and could barely hold up a wash-line. the slim, bare, copper wire snapped on the least provocation, and the circuit was "down" for thirty-six days in the first six months. the little glass-knob insulators made seductive targets for ignorant sportsmen. attempts to insulate the line wire were limited to coating it with tar or smearing it with wax for the benefit of all the bees in the neighborhood. the farthest western reach of the telegraph lines in 1847 was pittsburg, with three-ply iron wire mounted on square glass insulators with a little wooden pentroof for protection. in that office, where andrew carnegie was a messenger boy, the magnets in use to receive the signals sent with the aid of powerful nitric-acid batteries weighed as much as seventy-five pounds apiece. but the business was fortunately small at the outset, until the new device, patronized chiefly by lottery-men, had proved its utility. then came the great outburst of activity. within a score of years telegraph wires covered the whole occupied country with a network, and the first great electrical industry was a pronounced success, yielding to its pioneers the first great harvest of electrical fortunes. it had been a sharp struggle for bare existence, during which such a man as the founder of cornell university had been glad to get breakfast in new york with a quarter-dollar picked up on broadway.