160 



Intelligence and Miscellaneous Articles. 



A number of wheels, whose axes are denoted by a, b, c, act upon 

 one another. This is most easily effected by surrounding the cir- 



cumference with caoutchouc and pressing the wheels against each 

 other. The diameters of the wheels a and b are as I : \ ; a and c as 

 1 : J. The three wheels have three rods, d, e, f, which fit in the 

 horizontal slits on the sliders g, h, i, which move in a vertical direc- 

 tion. The sliders have pulleys, m, n, and^? ; over these, and, as is 

 seen from the diagram, over several other pulleys, passes a string, 

 zmnpsr, fastened at s, and provided with a pencil at s, and sup- 

 porting a weight r. The pencil 5 writes on the plate t, which is 

 moved by a string k v wound round the circumference of the wheel a. 

 The distance of the rods d, e, f relatively to the axes a, b, c, as well 

 as the initial positions of the lines ad, be, ef, can be regulated by 

 screws. 



If now the wheel a is set in motion by a winch, the pencil 5 de- 

 scribes a curve on the plate t. If x be its abscissa, and y its ordi- 

 nate, the curve has the equation 



y = a sin (x + a) + b sin (2x -f /3) + c sin (Sx -f- y), 

 in which the constants a, b, c depend on the distances ad, be, cf, and 

 the constants a, (3, y on the initial positions of the same lines on the 

 apparatus. This apparatus describes thus the curves of vibration of 

 various vocal, colours with reference to the three first partial tones. 



It is not necessary to be limited to this. The number of the vi- 

 brations which can be combined depends only on the number of the 

 wheels used, and the kind on their diameter. If the pencil is moved 

 backward and forward in one direction and the writing -plate in an- 

 other, we obtain Lissajous's figures. 



It is worthy of remark that, by means of such an apparatus, any 

 given functions may be represented as curves, which may be deve- 

 loped by Fourier's series. The differential quotients, or the inte- 

 grals of the same functions, are given by the apparatus with ease. 

 It therefore perhaps contains the germ of a future calculating-ma- 

 chine of a higher kind.— PoggendorfFs Annalen, November 1866. 



IAR. 1 



