i84 



NA TURE 



[December 26, 1901 



fundamental tone of the sound, the smaller to the harmonics 

 that enter into the composition of the compound tone on which 

 the quality of the vowel depends. 



These flame pictures are only seen for an instant, and many 

 efforts hnve boon made to fix them by photo!;r:iphic method? 



Marage,' to whose researches we shall afterwards refer, feeds the 

 capsule with acetylene, and thus obtains a luminous flame. The 

 result of such an arrangement is shown in Kig. 17. 



It will be observed that all manometric flames seen in a rota- 

 ting mirror arc inclined, ns their composition is due to a hori- 



FiG. 3. — Changes of t 



:pression during speech. Chronophotography. '1 en images per second. 



This was first attempted by Gerhardt ' in 1877. He used the 

 flame of cyanogen, and the somewhat poor result is shown in 

 Fig. 16. 



Doumer- obtained a brilliant flame by burning carburetted 

 hydrogen in oxygen, and he also introduced into such re- 



zontal and vertical translation, and the faster the mirror is 

 rotated the more they are inclined. 



Efforts have also been made to analyse sounds by photograph- 

 ing a ray of light reflected from a vibrating minor. Long ago, 

 but without photography, Czermak applied this method to the 

 phenomenon of the pulse, and in 1879 Blake - devised a mirror 

 for thus recording speech. He used a small metallic plate, in 

 the centre of which was a small hook which is attached to a 

 very light mirror delicately swung on two pivots, i-, <, Fig. 18 



I'ic. 4.— Photophone of Demeny. A, glass disc carryinc the pictures ; 

 u, another disc, perforated ; i., electric lamp ; o, lens. 



searches a chronophotographic method by reproducing the 

 images of a flame acted on by a tuning-fork of known pitch. 



1 Stein: "Die I.iclit im Dicnstc wissenschaftlicher Forschung/' 

 (Leipsig. 1877). 



2 Doumer : C.K. de I'Acadimie des Sciences, 1886. 



NO. 1678, VOL. 65] 



. 5. — Phonautograph of Leon Scott. A paraboloid resonator, closed at 

 one end by a membrane, to which a light lever is attached, c is a 

 drum covered with smoked papcron which the lever traces a curve. As 

 c rotates, it moves from right to left. 



A ray of light is thrown on the mirror by a convex lens ; after 

 reflection it again traverses a lens and falls on a photographic 

 plate in movement. Sharp, well-defined images are thus 

 obtained (Fig. 19). 



' Marage : " Etude des Cornet Acoustiqu 

 Flammes Manometriijues de K<)nig " (1897). 



s Blake : American Journal of Science • 

 PhysiqiiCy 1879. 



s par la Photograpbie des 

 ../ Art, 1878 ; Journal dt 



