130 SCHOOL SCIENCE AND MATHEMATICS

SHORT STORIES OF GREAT INVENTIONS.1

BY A. L. JORDAN,Polytechnic Hig\k School, San Francisco, Cak

(Continued from January.)6. THE STEAM TURBINE is coming to be the modern colossus

of power, and for large units, especially in direct connection to

dynamos, is replacing the reciprocating engines. We now read ofthe construction of turbines of 40,000 horsepower! .

The reaction turbine of Hero has been mentioned, as has theimpulse or steam-jet type of Branca, but it was not "until 1883that the Swedish engineer De Laval brought out his remarkableimpulse turbine with its curved buckets and high speed, givinggreat power in small space. Parsons, in England, was close onhis heels (1884) with a multiple nozzle turbine of similar type.This was improved in various ways, and finally found a worthyrival in the combined impulse and reaction type of Curtis, inAmerica, in 1896. The last two were brought out in this countryby the Westinghouse and the General Electric Companies, re-spectively.

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7. WATER WHEELS. A paddle wheel, turned by a jet of water,has been known since the times of antiquity; "overshot" wheelshave been familiar to the Chinese for centuries;-and" "currentwheels55 ("undershot,75 sometimes on an anchored raft) probablyrevolved on streams in prehistoric times. A very early type isthe "breast wheel," a compromise between the overshot and under-shot.The use of curved buckets was first proposed by Euler, the

great Swiss mathematician, in 1754. Various forms of curvedbucket turbines were developed, especially in France, in the nextseventy years.’ One marked type, the "inflow turbine," was putforth by Poncelet in 1826 and developed in 1849 in this countryby J. H. Francis. Another, the "outflow turbine," by Fourney-ron in 1827, was brought out here. by Morris in 1843., A stilllater type, where the- flow is in, down, and out, has been namedthe "American." -These were intended for low head.

Going back to the flat paddle wheel, we find that the earlyCalifornia miners, having numerous water jets at hand, usedtheir crude "hurdy-gurdys" for sawing lumber,; etc. .The firstsuggestion for an impulse water wheel came from ProfessorHesse of the University of California in 1867, and he had asmall wheel built and tested then, but did not patent it. The

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first patent was that of Pelton in 1880. An improvement in theshape of the bucket (ellipsoidal, with a recess in the lower part)was patented by Doble, the patents being recently acquired by thePelton Company. The Pelton and Doble wheels, developed onthe Pacific Coast, are in use in most o’f the high head water powerplants of the world.

O’ne other kind, the reaction wheel (original form being Hero’sengine) was adapted to water power by Barker (Am.) in 1740.This wheel is rarely used now, but finds an application in the com-mon lawn sprinkler.

8. THE HYDRAULIC RAM was invented by pTohn Whitehurst(Eng.) in 1772. In his crude appliance, the valves were closedby hand. Joseph Montgolfier (one of .the brothers who sent upthe first hot-air balloon) made a practical machine of it by addingthe automatic feature in 1796.A more recent device which has been added is a small valve for

sucking in the air necessary for operation. After the momentumof the moving column of water is checked, if there were no recoil.the pressure would (in many cases)’ not be reduced sufficientlyto allow the main valve to open.Another interesting application of the ram is its use with a large

flow’ of impure water to pump a small amount of pure water toa considerable height.

9. WIRELESS. TELEGRAPHY had its beginning when the body ofa frog was seen to twitch when a frictional machine was workednear it about 1750.The existence of a ^universal ether^ was suggested by Huygens

in 1678; Faraday showed some experiments proving its existencein 1845; and the great English physicist Maxwell in 1864 statedthe possibility of waves in this ether. Felix Savary in 1827 hadobserved the variations in polarity of a steel needle magnetizedby the discharge from a Leyden Jar. Joseph Henry (Am.) in1842 repeated this experiment, and proved that the spark dis-charge is oscillatory; and Hertz (Ger.) in 1888 showed-the trans-mission and reception of the waves set up by that discharge.(Hertz used a spark-gap detector, but the same device had beenused by the Thomson and Houston in 1875 and by Edison aboutthe same time.)

S. P. Thompson came very near to Hertz’s discovery in 1876,when he noticed sparks between two door keys fastened closetogether on a block of wood.

Professor Branly, in France, invented an important form of

132 SCHOOL SCIENCE AND MATHEMATICS

coherer in 1890; but, one year earlier, coherer action betweenpieces of metal had been noticed by the Englishman Lodge, whoalso discovered the important principle of syntonizing.These were not the first recorded observations on coherers.

Munk (1835) noted increased conductivity in tin filings, loosecarbon, etc., after a Leyden jar discharge; S. A. Varley (1852)found the same thing after an atmospheric discharge; Hughes re-discovered Munk’s experiment in 1878; and Calzecchi-Onesti madea similar observation in 1884.,Tesla, the Austro-American inventor, patented his high-fre-

quency coil in 1891. Marconi, in 1899, using the Tesia coil, theoscillatory discharge, and the coherer, and adding two importantfeatures (ah elevated aerial and powerful discharges), astoundedthe world by signaling across the Atlantic Ocean. Other experi-menters in "wireless signals" were Preece, Henry, Edison, andTrowbridge, as well as Tesla.

Mention should be made of detectors other than coherers. Onewas the hysteresis magnetic detector (Rutherford and Marconi),another the vacuum valve detector (Fleming in 1904, De Forestlater). The latter invention, however^ was antedated by thework of Edison, who used a vacuum bulb as a "rectifier" in 1884.The first important type of "crystal" detector, now in such com-mon use, was the carborundum detector of General Dunwoody(U. S. Army) in 1906. Discovery of the electrolytic detector-isclaimed for Fessenden (1903), Ferrie, Nernst, Vreeland, andSchlomilch, but Pupin is credited with the original use of a similardevice for rectifying alternating currents in 1898.

10. THE TELEPHONE is, like the other inventions, the culmina-tion of a series of ideas. Charles Bourseui in 1854 suggested a

flexible disc "to make and break the current from a battery."In Germany, in 1860, Reis produced a singing or "musical" tele-phone. He died unknown and neglected, but his apparatus,though imperfect, embodied the great principle.The next development shows one of the most extraordinary

coincidences in the history of invention. Alexander Bell ofBoston and Elisha Gray of Chicago, within two hours of eachother, February 14, 1876, applied for caveats for a telephoneinstrument at the patent office. This instrument was the onenow used as the receiver. Over this there was an enormousamount of litigation, Bell winning the suit, partly because of prior-ity, partly because his specifications showed better knowledgeof the subject.

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The microphone transmitter was invented by Berliner in 1877;Edison followed, three months later, with a carbon transmitter ofplumbago; and Hughes, Blake, and Hunning introduced otherimprovements. Berliner^s patent was contested by Edison, Gray,Richmond, Dolbear, Holcombe, Bell, and others, but after four-teen years of litigation it was awarded to Berliner, and was laterbought by the Bell Company.The thoughtful mind is filled with wonder at being able to

catch even the inflections of a friend^s voice, and now the tele-phone engineer amazes us with his conquest of distance. Youcan talk from New York to San Francisco’!

11. THE ELECTRIC TELEGRAPH. The beginning of telegraphywith wires was in 1673 when Otto von Guericke, working withhis newly invented frictional machine, noted the distinction be-tween conductors and insulators. Using wires to conduct electriccharges was rediscovered by Stephen Gray in 1729 in England.The French physicist Ampere suggested the possibility of electro-magnetic signals at the .distant end of a wire in 1821, but thefirst actual apparatus was that of our own Joseph Henry in 1830.Pie used a permanent magnet and a bell, running the wires aroundhis lecture room. The first working telegraph in Europe wasthat of Gauss and Weber in 1833, and in England Wheatstoneand Cooke had a successful system in 1837. In the UnitedStates the idea (using the electromagnet) was patented by Morse,and the first telegraph message was sent by him in 1844.

Steinheil (Ger.) in 1837 discovered the great saving of wireby the use of the "earth return," but it is interesting to notethat this was used by Franklin many years before when he senta discharge of static electricity under the Schuylkill River.

Submarine telegraphy needed a far more sensitive instrumentthan the telegraph relay or sounder, and this demand was met byLord Kelvin who,brought out his mirror galvanometer about1857. This was followed by his siphon recorder (moving coil)in 1865. The next great improvement was the "duplex" and thenthe "quadruplex" (the latter now used mostly for land lines)by Edison in 1872-73. Meanwhile, in England,. Wheatstone com-pleted his automatic telegraph (1868). This now allows a speedof five hundred words per minute. Later schemes of rapid ormachine telegraphy, printing telegraphs, etc., have been numer-ous, but in spite of the telephone and even of wireless telegraphythe old "Morse" is still clicking out the great news service of theworld. (To be continued.)