EXPERIMENTAL PHONETICS. 



249 



atteiiiptod l»y ( icrhsirdt '' in ISTT. He used the lliinic of ex iiiiolicii. 

 iind tlie somewbsit poor result is shown in tiy. !<;. 



Doimier'' obtained a brilliant tianie by l)urning- earburetted liydrooen 

 in oxgen, and he also introduced into such researches a chrono})hoto- 

 graphic method by reprodueino- the images of a flame acted on by a 

 tuning fork of known pitch. ^larage,' to whose researches we shall 

 afterwarils refer, feeds the capside with actylene, and thus obtains a 

 luminous flame. The result of such an arningcnKMit is shown in flg. 17. 



It w ill be observed that all maiiometric flames seen in a rotating 

 mirror are inclined, as their composition is due to a horizontal and 

 vcM'tical translation, and the faster the mirror is rotated the more th(\v 

 are inclined. 



Fk;. 14. — Koiiig-'H apparatus, a ■Maiiometric fai)snlo; M, rotating mirror. 



Ett'orts have also been made to analyze sounds by photographing a 

 ray of light reflected from a vibrating mirror. Long ago, but with- 

 out photography, Czermak applied this method to the phenomenon of 

 the pulse, and in 18Tl> Blake'' devised a mirror for thus recording- 

 speech. He used a small metallic plate, in the center of which was a 

 small hook which is attached to a very light mirror delicatel}' swung 

 on .two pivots, (\ (', fig. 18. A ray of light is thrown on the mii-ror 

 by a convex lens; after reflection it again traverses a lens and falls on 

 :i photographic plate in movement. Sharp, well-detined images are 

 thus obtained (flg. 19). 



«Stein: Die Licht iin dien^te wissenschaftlicher Forschung (Leipzig, 1877). 

 ''Doumer: C. R. de rAcadeinie des Sciences, 1S86. 



'Marage: Etude des Cornet Acoiistiques i)ar la Pliotograpliie des Flanuiics .Mano- 

 metri(jues de Knnig (1897). 



''Blake: American Journal of Science and .\it, 1S7S; .Tonrnal di- Pliy.siiiue, 1S7!). 



