PROCEEDINGS 



OF THE 



AMERICAN ACADEMY 



OF 



ARTS AND SCIENCES. 



VOL. XXV. 

 PAPERS READ BEFORE THE ACADEMY. 



I. 



CONTRIBUTIONS FROM THE PHYSICAL LABORATORY OF THE 

 MASSACHUSETTS INSTITUTE OF TECHNOLOGY. 



XXXIV. — TELEPHONIC SPECIFIC INDUCTIVE 

 CAPACITY. 



By F. H. Safford and G. U. G. Holman. 



Presented by W. W. Jacques, December 11, 1889. 



In a paper on the Construction of Telephone Circuits, read before this 

 Academy on the loth of June, 1887, by the Electrician of the Ameri- 

 can Bell Telephone Company, Dr. Jacques, it was pointed out " that 

 the readiness with which telephonic conversation may be carried on 

 over any circuit, whether made up of cables or pole lines, or both, 

 depends, — 



" 1. On the total electrical resistance of the circuit joining together 

 the two stations. 



" 2. On the total electrostatic capacity of this circuit." 



And the general rule was laid down : — 



" No matter what may be the distance between two points, good 

 business conversation may be carried on between them, provided they 

 be connected by a pole line or cable, or both, the product of whose 

 total resistance by its total capacity is less than 2,000, if transmitters 

 of the Blake type be used, and less than 4,500, if transmitters of the 

 Runnings type be used." 



VOL. XXV. (N. S. XVII.) 1 



