THE MONOCHORD 357 



3r the purpose iron cross-pins inserted into the upper holes. The 

 ndof the string is passed through the lower hole in the pin, wound 

 ound it by turning the latter several times and tightly stretched. 

 Common piano-wires, O8 or l mm thick, may be used, or even unan- 

 ealed iron wire. As the ends of the wires are apt to break, they 

 hould be made red-hot over the lamp ; one end, heated to a length 

 f about 6 cm , is bent double at half that length, and the double wire 

 5 twisted so as to leave a loop at the extremity ; of the other end 

 nly about l cm need be heated, as only a short portion at that end 

 3 bent at right angles for the purpose of passing the string through 

 he hole of the pin. Between the bridges, along the middle of the 

 lonochord, a straight line is drawn and divided into centimetres. 

 L conspicuous mode of marking the divisions, like that in fig. 163 

 jpage 236), will be found advantageous. 



; A small bar of wood, as long as the width of the monochord, 

 xactly as high as the bridges, and about 6 cm wide, will be required 

 )r the experiments with the monochord. 



The length of the strings is assumed in the following experiments 

 3 be 12U cm , which is the clear distance between the two bridges. If 

 he monochord has only half this size the numbers which follow 

 i the text must of course all be divided by two. 



Two strings may be stretched at once upon the 

 lonochord, although only one will be required to begin 

 r ith. As long as the string is rather slack, no proper 

 ote is produced, but this will be the case as soon as 

 lie string is sufficiently tight ; and when the string is 

 radually made more and more tense, the note given out 

 y it will be found to become higher and higher. The 

 !3ason of this is, that the string, which has been pulled 

 om its position of equilibrium by the finger, returns 

 .0 the former position as soon as it is released, in con- 

 jquence of the tension, and its motion is the more rapid 

 le greater the force acting upon it, that is, the greater 

 le tension, or the tighter the string. When the string 

 :rives at its position of equilibrium, there is a certain 

 Tiount of work in it, and by its inertia it passes to the 

 oher side of the position of equilibrium until the accu- 



