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check to the whole vibration of the violoncello, producing not 
merely beats, but a baying sound, destitute of the freedom of 
vibration which characterizes other notes. 
But a great objection to the above explanation is this ex- 
vyeriment. On an Italian instrument, the upper D on the 4th 
or lowest string is the imperfect note. But when the same 
note is elicited from the 3rd string, the note is perfectly reson- 
ant. This peculiar effect seems then to depend upon the point 
of the finger-board which is pressed. It is also well known that 
the “wolf” can be modified by an alteration of the position of 
the sound-post. As an explanation, we may conceive that the 
whole framework of the violoncello vibrates like a stretched 
string, producing its fundamental, with a series of overtones, 
and that a nodal line passes through the point of the finger- 
board, pressure upon which produces the “wolf,” and that thus 
all vibrations being destroyed except those which have a node 
at the point of pressure, this peculiar tone is elicited. 
Mr TROTTER said that if Mr Kingsley’s explanation of the 
cause of the “wolf” was the true one, it was to be expected 
that it should be produced when a certain note was sounded 
upon one string and not upon another. The fingering would 
be different in the two cases, and the note to which the finger- 
board responded would vary with the. point touched by the 
finger. 
(2) A description of the Instruments used in sounding 
some of the Lakes in the Snowdon District, and an 
account of the results obtained. 
Mr KINGSLEY gave a description of the Plummet, Registering 
Apparatus and Protractors used by him in sounding several of 
the deep lakes in the Snowdon district last June. 
The plummet is a modification of the deep-sea plummet 
now generally used, the principal alteration being in the appli- 
