OF ARTS AND SCIENCES. 263 



Lowell Free Courses given that year at tlie Institute of Technology. 

 It is probable that this experiment was prepared for and shown in 

 the lecture of this course which was delivered on January 5, 1870, 

 and related to sympathetic vibrations. 



On August 23, 1870, at the meeting of the American Association 

 at Troy, Professor R. H. Van der Weyde, of New York, presented 

 paper No. 141 to Section A, in the hall of the Troy Female Seminary, 

 Professor John M. Ordway acting as chairman. This paper w^as enti- 

 tled, " Further Improvements in the Method of transmitting, audibly, 

 Musical Melodies by the Electric Telegraph Wire." In the discussion 

 which followed the presentation of this paper, I described my experi- 

 ment, and pointed out that my difficulty was mainly with the trans- 

 mitter. Professor Van der Weyde's with the receiver; also that, if he 

 could combine his transmitter with my receiver, I thought he might 

 obtain valuable results. I have since been informed that he adopted 

 this suggestion, and ascribes to it the use of the metallic diaphragm 

 wliich he afterwards employed. The "Troy Press" of the following 

 morning, August 24, 1870, contained the following report of my re- 

 marks. On account of its importance, I may be pardoned for giving 

 it verbatim. 



" Professor Pickering described a simple means he had employed 

 for rendering these vibrations audible. It consisted of a simple elec- 

 tro-magnet placed close to the bottom of a large tin box, whose reso- 

 nance rendered the sound very intense. His remarks were greeted 

 with marked approbation. Another member said Professor Picker- 

 ing's method was beautiful in the extreme, because it did away with 

 the armature." 



Professor Charles R. Cross, then Assistant Professor of Physics 

 in the Institute of Technology, was invited to give a lecture on Sound 

 to the pupils of the New England Conservatory of Music, in February, 

 1872. He desired to show the experiment of telegraphing sound. 

 Accordingly, Professor Cross, Mr. Waldo O. Ross (who was present 

 at the experiment in 1870 also), and I spent an evening at the Insti- 

 tute, and repeated the experiment of 1870 under more favorable 

 conditions. The great difficulty in the early experiment was witli the 

 transmitter. A tuning-fork was accordingly substituted for tlie sonom- 

 eter, which enabled the circuit to be broken with greater certainty and 

 regularity. It was, however, open to the objection, that sounds of one 

 pitch only could be transmitted. The details of this experiment are 

 known with much greater certainty than those of the first experiment. 

 The battery consisted of six small Grove cells. An " Albert Biscuit " 



