. Practical physics. first introduced the principle upon which all successful flight byheavier-than-air machines now depends, namely, control of stability by the warp-ing of wings, or by ailerons (hinged attachments to wings), in connection with theuse of a rudder. The upper panel shows one of the original gliders (WilburWright inside) with which the AVrights first mastered the art of gliding (1000-1903) and made more than a thousand gliding flights, some of them GOO feet long,following in this work th(> priru-iples of gliding flight first demonstrated byLilieiithal and a little later, much
. Practical physics. first introduced the principle upon which all successful flight byheavier-than-air machines now depends, namely, control of stability by the warp-ing of wings, or by ailerons (hinged attachments to wings), in connection with theuse of a rudder. The upper panel shows one of the original gliders (WilburWright inside) with which the AVrights first mastered the art of gliding (1000-1903) and made more than a thousand gliding flights, some of them GOO feet long,following in this work th(> priru-iples of gliding flight first demonstrated byLilieiithal and a little later, much more com]>letely, by Chanute of Chicago (). The lower panel shows the first successful power flight in the history of theworld (Orville Wright in the machine, Wilbur running beside it as it rose fromthe track). Four such flights were made on the morning of December 17, 1003,the longest of which lasted 59 seconds and covered a distance of 852 feet agaiuat a 20-mile wind INDUCTION COIL AND TRANSFORMER 317. Fig. 338. The modem receiver A modern telephone receiver is shown in Fig. 338. Itconsists of a permanently magnetized U-shaped piece of steelin front of whosepoles is a soft-irondiaphragm whichalmost touches theends of the mag-net. Wound inopposite directionsupon the two polesare coils of fineinsulated wire mseries with each other and the line wire. G is the earpiece,E the diaphragm, A the U-shaped magnet, and B the coils,consistmg of many turns of fine wire and having soft-ironcores. When the rapidly alternating current from the secondarycoil s (Fig. 337) flows through the coils of the receiver,the polesof the permanent magnet are thereby alternately strengthenedand weakened in synchronism with the sound waves fallingupon the diaphragm of the transmitter. The variations inthe magnetic pull upon the diaphragmof the receiver cause it to send outsound waves exactly like those whichfell upon the diaphragm of the trans-mitter. Telephonic conversation can be car-ried o
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectphysics, bookyear1922
