34^ Ohfervat'ions on the 



C and D, vnll, by the vibration of the firing, be thrown from 

 it. The points C and D are called vibration nodes. In this, 

 and all the other experiments of this kind, the point where 

 the bridge ftands is alfo a vibration node. 



II. Divide the firing AB into a number of equal parts at 

 pleafure, for example five ; cut off, by removing the bridge 

 to E, two of thefe parts (this number % and the other 5 

 jnuft have i for a common divifor) ; place upon the points 



of divifion C, D, F, and any others of 

 the flrinsf taken at pleafure, liiht bo- 



. -_, dies, fuch as bits of paper ; draw the 



violin bow over the part EA. and all 

 the bits of paper except ihofe on G 



and D will then be thrown oft', and you will hear a tone 



which is to the tone of the whole firing as 5 : 2, and whi( h 



correfponds to the tone of the part EA. 



III. Divide a firing AB into any number of equal parts, 

 for example fix, by the points C, D, E, F, G ; cut olf as be- 

 fore, by removing the bridge to F, tv\o parts (this number :?, 

 and 6 the number of the parts of the whole firing, muft have 

 ^ greater common divifor than i); place upon the other fou^ 



points of divifion C,D,E, G, and 



„ _ on any others of the flrine; taken at 



o T\ "F* T^ f^ 



A -D pleafure, light bodies, fuch as bits 



of paper ; and all thefe, except that 

 at D, will be thrown down by rub- 

 bing the bow againft FB, the part cut off by the bridge ; you 

 will alfo hear a tone correfpopding to the part FB, which is 

 to the tone of the whole firing as 6 : a or 3 : i . 



IV. If you place upon the ftring, without cutting off any 

 part of it by the bridge, different bits of paper in points 

 taken at pleafure, ai^d rub with the bow fo as to make the 

 whole ftring found, all the \)\i^ of paper will be thrown from 

 it. This experiment will give the fame refult when yon cut 

 off in the middle t^e part of the ftring which a6lually founds ; 

 for example, you may vary the fccond ex^icriment thus : — 



$ Y. Divide 



