Blake Transmitter Page 3

Berliner and Blake

In 1877, after reading about Bell's liquid variable resistance transmitter, Emile Berliner (German migrant to the USA) tried to make the idea practical. A tireless after hours experimenter, he succeeded and filed a caveat (warning of intent to patent) on a simple microphone. Bell declined an offer to purchase, but later their patent attorneys found him again, and Thomas Watson brought Berliner on board in 1878, partly to control rights to the instrument ahead of Western Union, and to get Berliner's (good) step-up transformer patent. Aitken (1939) and others expose a twisted web of patent litigation lasting up to 1893 around this transmitter - (produced in small numbers in the U.S. and in Europe). The actual patent was not granted until 1892 after controversial patent office wrangling, and it seemed to have been rewritten several times by Bell experts. The aim was competitive - not to protect the long-superseded Berliner transmitters - but to prolong Bell's (US) patent monopoly on the principle of the microphone far beyond the normal patent life. (As with the Blake and Berliner, transmitters were separately licenced overseas).



Francis Blake came from an established, though less well-off, American family. He was however very clever, and a meticulous worker, though his insecurities and faults of temper made him "exacting, precise, proud and inflexible" (Hall 2003) - and reactive to any perceived criticism. After starting work at age 15 with the United States Coast Survey, his precise, hard work led him to very responsible tasks - such as working on the French end of a project to accurately calculate transatlantic longitudes, via the underseas telegraph cable. Later he "married into money" - ironically to a girl surnamed Hubbard, the same as Mabel Bell's maiden name but no relation. This enabled him to ease out of regular, paid Coastal Survey work, and to concentrate on inventing. Blake was famous for pioneering work in high speed photography, and he invented in other fields as well as in telephony.

Blake's Coastal Survey supervisor, Julius Hilgard, had been one of the judges who awarded Bell a medal at the 1876 Centennial Exhibition, and from him Blake first learned of the Telephone. "The telegraphic work Blake had done … at the Coast Survey… had provided him with a highly sophisticated knowledge of electricity", and by January 1878 he worked hard at improving Bell's feeble receiver-transmitter. "He read the latest professional literature on microphones" (Hall, 2003) and after considerable experimentation produced a working model. "On October 18, 1878, Blake took (it) to the Bell Company offices in Boston, where it underwent thorough testing by Thomas Watson … the results left little doubt, (it) was better than anything else available." That is what assured Blake's transmitter its place in history. Thomas Watson had struggled desperately to find something better than Edison's model - and when "Frank Blake came along with his transmitter, we bought it". At last Bell had a transmitter that was "as good or better than Edison's" and so was confident to sue Western Union (via the manager of their "American Speaking Telephone Company") for patent infringement- a battle they (improbably) won, when Western Union settled out of court and surrendered all its patents and all telephone business to its tiny rival (Harlow, 1936)
Success was not instant, however. Berliner had been on the Bell payroll trying to perfect his transmitter, and though some were made and used they were never a great success. He was, however, around the Charles Williams workshops when Blake's invention was purchased, and its problems engaged his attention. Blake had nearly exhausted himself getting his device as far as it was, and it seemed he could not get it any further. Early models constantly went out of adjustment and users had to be trained to get coherent speech: "such an instrument was entirely unfit to be placed in commission" (Wiles, 1926). Blake finally retreated to his country workshop - the nervous strain was too much.

One problem was a tendency of the diaphragm to resonate harmonically, generating strong overtones causing speech over early models to sound so distinctly strange that it was nicknamed "telephone talk". Edmond Wilson, a Bell employee working with Blake, suggested (and patented) the rubber ring around the diaphragm edge (present on all Blakes we see, although often hardened and broken away with time). Berliner set to , and eventually made two significant improvements. He straightened and strengthened the contact leaf springs (previously curved) and altered the two damping springs to the configuration we know today. He also changed the soft carbon button for "a hard, dense carbon (as) formed in city gas retorts" at very high temperature, because the platinum point of the other contact was eating the button out and ruining the adjustment. Berliner went to great lengths to produce these glass hard carbon buttons, and personally supervised their manufacture, to his specifications, in the Boston Gas Works. " (His) process remained the standard method of treating the carbon buttons as long as Blake transmitters were manufactured" (Wile, 1926).

Berliner wrote "After … the Blake transmitter had been perfected, orders were given that 200 a day should be made for us. These were tested by myself and Mr Richards, and once adjusted, they remained in first-class working order. I personally tested the first 20,000 transmitters…" (Wile, 1926). Francis Blake was also a skilled negotiator, and he made a lucrative, ongoing deal with Bell to secure royalties, including the rights to manufacture outside USA - which netted him a lot of money, despite complications in Britain where the United, then the National, Telephone Company eventually ended up owning the rights. However the Bell Co. diplomatically acknowledged the work of other people on the device - hence the names Berliner, Bell and Edison (after the Western Union settlement) were stamped on the wood of early models, with a list of relevant patents on the side panel - along with the words "Blake Transmitter" (Hall, 2003)

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