SCIENTIFIC RECREATIONS. 



distortions noticeable in M. Lissajon's experiments. Fig. 178 has been traced 

 in the exact ratio 2:3; fig. 177 in the ratio 1:2; and fig. 179 corre- 

 sponds to the ratio I : 2 and a small fraction, which causes the irregularity 

 of the figure. 



In considering the harmony of figs. 177 and 178, the first of which corre- 



un 



Fig. 182. Method of constructing an Harmonograph. 



sponds to the octave, the second to the fifth, whilst fig. 179 corresponds to 

 the disagreeable interval of the ninth, one is almost tempted to put a certain 

 faith in the fundamental law of simple ratios as the basis of harmony. At 

 first sight this appears beyond doubt, but perhaps musicians would be hardly 

 content with the explanation. M. Tisley's Harmonograph, it will be seen, 

 is a -rather complicated apparatus ; and I will now explain how it may be 



Fig. 183. The apparatus completed. 



constructed by means of a few pieces of wood. I endeavoured to construct 

 as simple an apparatus as possible, and with the commonest materials, feeling 

 that it is the best means of showing how it is possible for everybody to 

 reproduce these charming curves of musical intervals. Also I completely 

 excluded the employment of metals, and I constructed my apparatus entirely 

 with pieces of wooden rulers, and old cigar boxes. I set to work in the 



