266 PROCEEDINGS OF THE AMERICAN ACADEMY 



The following extract from a letter to Professor Bell may also be 

 of interest, as showing that I advised him to increase the sound of his 

 telephone by an instrument resembling the Blake transmitter, in 1877, 

 or two years before the invention of that instrument. This letter was 

 written during the night following Professor Bell's commuuication on 

 the telephone to the American Academy, on May 4, 1877. The tele- 

 phone then exhibited gave a very feeble sound, and, according to 

 my letter-book, I wrote on " the problem of introducing more kinetic 

 energy into your telephonic circuit, — in other words, on making a 

 telephonic relay. An idea occurred to me which I hope may give the 

 desired result, and I shall be very glad if you have the means of giving 

 it a trial. The problem is to utilize a local current, so that in a given 

 circuit it shall be proportional to the current induced by the magnets. 

 Now this may be done by attaching to the plate of the receiving tele- 

 phone A, a fine wire, dipping in water, and nearly touching a wire 

 connected with a second telephone and battery. The resistance of this 

 circuit will be mainly that of the water between B and C. Now, as A 

 vibrates, the interval B C will alter, and with it the total resistance, 

 and consequently the current. Moreover, a feeble exciting current 

 may regulate a powerful local battery." A sketch of the apparatus 

 showed that the current from the battery passed through the vibrating 

 diaphragm of a receiving telephone, to which was attached a wire B, 

 dipping in water, and nearly in contact with a second wire C. The 

 variations of the current thus magnified were then passed through a 

 second telephone. A modification of the apparatus was also described, 

 by which the current could be reversed, like the primary current. Had 

 this instrument been tried, a loud-sounding telephone might have been 

 obtained earlier. A carbon button should have been substituted for 

 the liquid resistance, as the varying resistance of carbon was then well 

 known. 



No secret was ever made of these experiments, which were described 

 and exhibited publicly and privately whenever this was desired. A 

 patent for the apparatus was not taken out, from a belief that a scien- 

 tific man should place no restrictions upon his work which would tend 

 to prevent the repetition of an experiment of scientific interest. A 

 full description should have been published. This was at first delayed 

 from the pressure of other work and lack of appreciation of the im- 

 portance of the results. Afterwards I was unwilling to enter into a 

 controversy, or to obstruct my friends, who were struggling to obtain 

 proper recognition of the great results they had obtained in the same 

 field. Now that some of thera, at least, have been amply rewarded, a 



