460 Prof. Barton and Mr. Ebblewhite on 



used. The dimensions and magnifications were then as 

 follows : — 



AH = 13 cms., u = 11° 27 f , 6 = 7° 5', I = 0*68 cm.; 



W AR ^an- J| . 29 = 101 , L 



A / tana— tan 0*68 



The string's motion was magnified twice ; hence the ratio 

 of the two or the relative magnification, which is undisturbed 

 by reproduction, is 50*5. 



The value 101*1 of the magnification of the bridge's motion 

 was substantially confirmed by introduction of a fragment of 

 blown glass under the foot of the optical lever, the consequent 

 displacement of the spot being measured and the thickness of 

 the glass determined by a spherometer. 



The foot of the optical lever which touched the plane on 

 the bridge was made hemispherical on an oilstone, the work 

 being tested by a microscope. In like manner the other two 

 feet, which rested in the hole and slot, were made truly 

 conical. 



As to the interpretation of the abscissae and ordinates of 

 the curves on the prints, 



(1) the beginning of the time is in all cases at the left 



side ; 



(2) the ordinates for the string's motion are always in- 



verted, i. e. an upward motion of the shadow of the 

 string means a motion of the string towards the belly 

 of the violin ; 



(3) the ordinates for the vertical motion of the bridge are 



also inverted ; and 



(4) for the longitudinal motions of the bridge an upward 



ordinate denotes a displacement of the bridge towards 

 the " nut," i. e. towards the peg-box of the violin. 



Asymmetry of the Violin. — The necessity for dealing with 

 both the upper corners of the violin bridge suggested itself 

 to us on account of the well-known asymmetry of such 

 instruments ; for the strings are lower in pitch, and therefore 

 slacker, on one side and tighter on the other, the pitches 

 being respectively g, d', a', e" on Helmholtz's notation. Thus 

 the G-string side of the bridge has less pressure from the 

 string on its upper edge and less where its foot touches 

 the belly than is the case for the E-string side. Further, 

 because of this asymmetry of the tensions and pressures 

 of the strings, the body of the violin is asymmetrical also. 



Fig. 4, reproduced from a photograph of the Old English 



