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Dr. W. Huggins. 



[May 24, 



the bridge. In a contrary condition of things the sound-post should 

 be farther from the bridge. The extreme range needed in different 

 violins is about a quarter of an inch. At the same time any shift of 

 the post must affect the relative mobility of the two sides of the belly. 



If the sound-post transmits vibrations, these will be in addition to 

 those received from the sides of the violin. It may be, therefore, that 

 one condition which determines the best position of the post, is the 

 degree in which from their form and material these fulfil this duty. 

 All the sides must share in this duty, but the touch-rod shows that a 

 large part of this action is borne by the parts of the sides which 

 curve inwards under where the strings are bowed. It is in harmony 

 with this view that Mr. Hill states, that if the inside blocks at the 

 corners, which are put to strengthen these parts, extend in a small 

 degree into these curved portions, the tone is injured. 



The plane of the vibrations of the strings is that in which they are 

 bowed, which is more or less oblique to the bridge. The vibrations 

 may be considered divided into two sets at right angles to each 

 other, a and h. 



The touch-rod shows that these vibrations exist strongly in the 

 upper part of the bridge. I venture to suggest that the use of the 

 peculiar cutting of the bridge, which was finally fixed from trials by 

 Stradiuarius, is to sift the vibrations communicated by the strings 

 and to allow those only, or mainly, to pass to the feet which would 

 be efficient in setting the body of the instrument into vibration, 

 the other vibrations which would be injurious in tending to give a 

 transverse rocking motion to the bridge being for the most part 

 absorbed by the greater elasticity given to the upper part of the bridge 

 by the cutting. Below the two large lateral cuts the touch- rod shows 

 a very great falling off of the vibrations h. In the case of a violon- 

 cello these vibrations were also very greatly reduced below the side 

 openings of the bridge. 



The violin on which the experiments were made was without a bass 

 bar, which is a piece of pine glued to the under side of the belly on 



