48 TRANSACTIONS OF THE [nov. 12, 
difference-tones from two notes which are both inaudible by 
reason of their very high pitch. Earlier attempts were with 
rectangular bars, which, when struck on the corner, vibrate at one 
rate in one transverse direction and at another in the transverse 
direction perpendicular to the first. These difference-tones 
only last a very short time, and for this reason the method was 
abandoned. On taking up the subject again he was able, with 
specially constructed whistles, to hear the difference-tone pro- 
duced by two whistles, the notes of both being too high to be 
heard when sounded alone. Konig, of Paris, has now made a 
set of forks, which individually are inaudible, and yet their 
difference-tones are audible. 
The paper was discussed by Professors Pupin, Rees and 
Hallock. 
The Section then adjourned. Wm. Hatiock 
Recording Secretary of Section. 
StTateD MEETING. 
November 12th, 1894. 
Thirty-five persons present, President J. K. RExEsin the chair. 
The following new members were elected: 
Prof. Dr. BonustAv Brauner, Corresponding Member. 
Joun JAcoB Astor, Resident Member. 
J. C. PristerR, Resident Member. 
A motion was carried granting to the council power to make 
the needful arrangements for the second annual reception. In 
support of this measure, Prof. H. F. Osborn spoke, calling 
attention to the success of the last reception and urging the 
importance of an annual meeting which should serve the func- 
tion of the conversazione of the Royal Society. 
The Biological Section then organized with Prof. Britton in 
the chair. 
