. Bulletin. Science. -c^^J r*- '^ â â^r E 3 _,ââ ti;ii -3 ft 1 Fiq. -c^J Figure 78.âPatent drawings of Watson's polarized ringer. From patent 210886 (December 17, 1878). earlier claims to priority made by Bell and by Edi- son.^'' In 1903 the United States Supreme Court finally declared the Berliner patent valid but restrict- ed the claims of this patent to metal electrodes.^* In its 1903 ruling the Supreme Court decreed that Berliner's patent application disclosed invention but added nothing of practical value to the telephone. Because Berliner's patent was limited to the use of metal
. Bulletin. Science. -c^^J r*- '^ â â^r E 3 _,ââ ti;ii -3 ft 1 Fiq. -c^J Figure 78.âPatent drawings of Watson's polarized ringer. From patent 210886 (December 17, 1878). earlier claims to priority made by Bell and by Edi- son.^'' In 1903 the United States Supreme Court finally declared the Berliner patent valid but restrict- ed the claims of this patent to metal electrodes.^* In its 1903 ruling the Supreme Court decreed that Berliner's patent application disclosed invention but added nothing of practical value to the telephone. Because Berliner's patent was limited to the use of metal electrodes, it did not infringe on the use of carbon transmitters in telephones. Edison's claims to priority in the invention of the carbon trans- mitter were maintained throughout the lengthly litigation concerning telephone transmitter patents. However, by the end of the legal battle, the American patent rights on his transmitter were lost because his European patents had expired. When a European patent had expired, its American counterpart was also invalid. But long before the courts had reached these deci- sions, commercially successful carbon transmitters had been invented and placed in operation. The first of these (figs. 74, 75) was designed by Francis Blake ^' early in 1878. In Blake's transmitter a platinum bead was fastened to the back of the diaphragm, and the diaphragm pushed the bead against a carbon block. Blake offered his transmitter to the Bell Com- pany, and it was promptly purchased. At first this transmitter gave quite a bit of trouble until Berliner showed how a harder carbon block would improve it. This modification made it a more sensitive instrument than Edison's transmitter and capable of providing a more powerful signal than either the Bell or Edison device. After Blake's instrument was patented in England on January 20, 1879, and in the United States on November 29, 1881, it was used extensively for some years by the Bell Company as standard equ
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