FRANCIS RT.AKE. 419 



FRANXIS BLAKE (1850-1018) 



Fellow in C'Inss I, Section 2. ISSl 



Francis Blake was the son of Francis antl Caroline (TnnnbuU) 

 Blake of Xeedham. 



June 25, 1873, he married Miss Elizabeth L. Hubbard, daughter of 

 Charles T. Hubbard of Weston, Avho survives him, together with one 

 son and a married daughter. 



]Mr. Blake completed his school training on graduating from the 

 Brookline High School in 186G. Shortly thereafter he entered upon 

 scientific work for wdiich he had a great predilection, in the United 

 States Coast Survey, remaining in this service for thirteen years. 

 During this time he took part in the remarkable work carried on by 

 the Survey in the telegraphic determination of longitude in the course 

 of which were determined the differences of longitude between the 

 foreign observatories at Greenwach and Paris and the American 

 observatories at Cambridge and AVashington, when for the first time 

 the transatlantic cable was employed to transmit the electric signal. 

 The accuracy of this work was such as to astonish the world. 



IVIr. Blake was exceedingly inventive and was strongly impressed 

 with the description which Professor Hughes published of his recently 

 iuAented microphone in the spring of 1878. At that time the new but 

 rapidly developing art of telephony called for a more powerful and 

 more sensitive form of transmitter than was available, one which 

 should be free from the various imperfections that were present in 

 existing instruments. The original Hughes microphone, while exqui- 

 sitely sensitive, was entirely unfitted for practical use. ]\Ir. Blake after 

 studying the problem with a most remarkable appreciation of the de- 

 tails of construction \Miich would be necessary to ensure satisfactory 

 results, devised the well-known Blake Transmitter. This was tliere- 

 upon put into service by the Bell Telephone Co. in November, 

 1878. Among the novel devices in the working parts of the instru- 

 ment, the use of platinum as the material of the hammer electrode 

 and carbon for the an^■il electrode, the one carried by a flexible spring, 

 the other by a somewhat stiff spring, the complete separation of both 

 electrodes from rigid connection with the diaphragm, the surrounding 

 of the carbon an\al electrode with a mass of spun brass, all went to 

 secure a delicacy of operation and precise reproduction of the spoken 



