the age of invention-第33章
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machinery established research departments and employed inventors。 The times had indeed changed since the day when Morse； as a student at Yale College； chose art instead of electricity as his calling； because electricity afforded him no means of livelihood。
From Edison's plant in 1903 came a new type of the storage battery； which he afterwards improved。 The storage battery； as every one knows； is used in the propulsion of electric vehicles and boats； in the operation of block…signals； in the lighting of trains； and in the ignition and starting of gasoline engines。 As an adjunct of the gas…driven automobile； it renders the starting of the engine independent of muscle and so makes possible the general use of the automobile by women as well as men。
The dynamo brought into service not only light and power but heat； and the electric furnace in turn gave rise to several great metallurgical and chemical industries。 Elihu Thomson's process of welding by means of the arc furnace found wide and varied applications。 The commercial production of aluminum is due to the electric furnace and dates from 1886。 It was in that year that H。 Y。 Castner of New York and C。 M。 Hall of Pittsburgh both invented the methods of manufacture which gave to the world the new metal； malleable and ductile； exceedingly light； and capable of a thousand uses。 Carborundum is another product of the electric furnace。 It was the invention of Edward B。 Acheson； a graduate of the Edison laboratories。 Acheson； in 1891； was trying to make artificial diamonds and produced instead the more useful carborundum； as well as the Acheson graphite； which at once found its place in industry。 Another valuable product of the electric furnace was the calcium carbide first produced in 1892 by Thomas L。 Wilson of Spray； North Carolina。 This calcium carbide is the basis of acetylene gas； a powerful illuminant； and it is widely used in metallurgy； for welding and other purposes。
At the same time with these developments the value of the alternating current came to be recognized。 The transformer； an instrument developed on foundations laid by Henry and Faraday； made it possible to transmit electrical energy over great distances with little loss of power。 Alternating currents were transformed by means of this instrument at the source； and were again converted at the point of use to a lower and convenient potential for local distribution and consumption。 The first extensive use of the alternating current was in arc lighting； where the higher potentials could be employed on series lamps。 Perhaps the chief American inventor in the domain of the alternating current is Elihu Thomson； who began his useful career as Professor of Chemistry and Mechanics in the Central High School of Philadelphia。 Another great protagonist of the alternating current was George Westinghouse； who was quite as much an improver and inventor as a manufacturer of machinery。 Two other inventors； at least； should not be forgotten in this connection： Nicola Tesla and Charles S。 Bradley。 Both of them had worked for Edison。
The turbine （from the Latin turbo； meaning a whirlwind） is the name of the motor which drives the great dynamos for the generation of electric energy。 It may be either a steam turbine or a water turbine。 The steam turbine of Curtis or Parsons is today the prevailing engine。 But the development of hydro…electric power has already gone far。 It is estimated that the electric energy produced in the United States by the utilization of water powers every year equals the power product of forty million tons of coal； or about one…tenth of the coal which is consumed in the production of steam。 Yet hydro…electricity is said to be only in its beginnings； for not more than a tenth of the readily available water power of the country is actually in use。
The first commercial hydro…station for the transmission of power in America was established in 1891 at Telluride； Colorado。 It was practically duplicated in the following year at Brodie； Colorado。 The motors and generators for these stations came from the Westinghouse plant in Pittsburgh； and Westinghouse also supplied the turbo…generators which inaugurated； in 1895； the delivery of power from Niagara Falls。
CHAPTER X。 THE CONQUEST OF THE AIR
The most popular man in Europe in the year 1783 was still the United States Minister to France。 The figure of plain Benjamin Franklin； his broad head； with the calm； shrewd eyes peering through the bifocals of his own invention； invested with a halo of great learning and fame； entirely captivated the people's imagination。
As one of the American Commissioners busy with the extraordinary problems of the Peace； Franklin might have been supposed too occupied for excursions into the paths of science and philosophy。 But the spaciousness and orderly furnishing of his mind provided that no pursuit of knowledge should be a digression for him。 So we find him； naturally； leaving his desk on several days of that summer and autumn and posting off to watch the trials of a new invention； nothing less indeed than a ship to ride the air。 He found time also to describe the new invention in letters to his friends in different parts of the world。
On the 21st of November Franklin set out for the gardens of the King's hunting lodge in the Bois de Boulogne； on the outskirts of Paris； with a quickened interest； a thrill of excitement； which made him yearn to be young again with another long life to live that he might see what should be after him on the earth。 What bold things men would attempt！ Today two daring Frenchmen； Pilatre de Rozier of the Royal Academy and his friend the Marquis d'Arlandes； would ascend in a balloon freed from the earththe first men in history to adventure thus upon the wind。 The crowds gathered to witness the event opened a lane for Franklin to pass through。
At six minutes to two the aeronauts entered the car of their balloon； and； at a height of two hundred and seventy feet； doffed their hats and saluted the applauding spectators。 Then the wind carried them away toward Paris。 Over Passy； about half a mile from the starting point； the balloon began to descend； and the River Seine seemed rising to engulf them； but when they fed the fire under their sack of hot air with chopped straw they rose to the elevation of five hundred feet。 Safe across the river they dampened the fire with a sponge and made a gentle descent beyond the old ramparts of Paris。
At five o'clock that afternoon； at the King's Chateau in the Bois de Boulogne； the members of the Royal Academy signed a memorial of the event。 One of the spectators accosted Franklin。
〃What does Dr。 Franklin conceive to be the use of this new invention？〃
〃What is the use of a new…born child？〃 was the retort。
A new…born child； a new…born republic； a new invention： alike dim beginnings of development which none could foretell。 The year that saw the world acknowledge a new nation； freed of its ancient political bonds； saw also the first successful attempt to break the supposed bonds that held men down to the ground。 Though the invention of the balloon was only five months old； there were already two types on exhibition： the original Montgolfier； or fireballoon； inflated with hot air； and a modification by Charles； inflated with hydrogen gas。 The mass of the French people did not regard these balloons with Franklin's serenity。 Some weeks earlier the danger of attack had necessitated a balloon's removal from the place of its first moorings to the Champ de Mars at dead of night。 Preceded by flaming torches； with soldiers marching on either side and guards in front and rear； the great ball was borne through the darkened streets。 The midnight cabby along the route stopped his nag； or tumbled from sleep on his box； to kneel on the pavement and cross himself against the evil that might be in that strange monster。 The fear of the people was so great that the Government saw fit to issue a proclamation； explaining the invention。 Any one seeing such a globe； like the moon in an eclipse； so read the proclamation； should be aware that it is only a bag made of taffeta or light canvas covered with paper and 〃cannot possibly cause any harm and which will some day prove s
