On the Telephone. 77 



resistance simply renders the sound of the voice of the distant 

 speaker fainter, as if he had gone further off, but in no way 

 alters the quality of the sounds heard. Professor Bell has even 

 spoken through a resistance of 60,000 ohms (the resistance of 

 the Atlantic cable is equal to 7,000 ohms). 



Various practical applications of the telephone at once suggest 

 themselves. It is already largely in use in the United States for 

 commercial purposes. It has been successfully tried in diving 

 and mining operations in this country. In physical research it 

 promises to be the starting point of new investigations, and as a 

 delicate phonoscope, or sound test, it will doubtless be most 

 useful both in the lecture-room and physical laboratory. The 

 telephone also reveals the existence of very feeble electric currents 

 by the audible vibration of its iron disc. So prompt and sensitive 

 is it to the slightest fluctuation in the strength of the current 

 traversing its coil that it is not unlikely it may be of use in searching 

 out rapid and feeble variations in a current that may escape 

 detection by a galvanometer, owing to the inertia of even a light 

 magnetic needle. Information as to the duration and character 

 of rapidly intermittent currents is needed in medical science and 

 not improbably the telephone may be able to furnish this infor- 

 mation, when associated with a chronograph. 



The first attempt to transmit sounds by electricity is due to 

 Philip Reis, teacher of natural history in a grammar school at 

 Freidrichsdorf near Homburg. A brief reference to what Reis 

 accomplished may here be of interest. I am indebted to Dr. 

 Messel, a name well-known to chemists, who was a former pupil 

 of Reis and eye-witness of his early experiments, for the following 

 interesting letter on this subject: — 



" Reis' first experiments date as far back as about 1852. But at that 

 time ended in failure, and were not resumed as far as I know till 1860. 

 The first publication about Reis' telephone appeared in a daily paper of 

 Frankfort^on-Main, which however I have not succeeded in procuring. 

 Reis gave his first public lecture on October 26th, 1861, when he showed 

 his telephone before the Physikalische Yerein (Physical Society) of 

 Frankfort-on-Main, and I send you herewith a copy of his paper. 



" The original telephone was of a most primitive nature. The trans- 

 mitting instrument was a bung of a beer barrel hollowed out, and a cone 

 formed in this way was closed with the skin of a German sausage which 

 did service as a membrane. To this was fixed with a drop of sealing 



