GRA.PHIC RECORDING OF SPEECH VIBRATIONS 
85 
of apparatus (phonograph, phonodeik and manometric flame) 
which have been brought nearest to mechanical perfection, have 
all been developed out of exceedingly defective and seemingly 
unpromising types. It is therefore precarious to reject any 
type of apparatus on a-priori grounds, and surely worth while 
to study the problem of perfecting existing types of apparatus 
and devising new ones. 
Enlargement of phonographic and gramophonic records. It is 
highly probable both on practical and theoretic grounds that 
the direct phonautograph type cannot be perfected to produce 
accurate sound curves large enough for direct reading. This 
appears both from the negative results attending long years 
of efforts and experiments directed to improving the pho- 
nautograph, ^ and from the fact that the degree of magnification, 
the inertia, length and flexibility of levers, and the amplitude of 
vibration demanded at the recording point are so great that the 
physical mechanism cannot conform to the rapid and com- 
plexly changing phases of speech vibration, and also necessarily 
introduces interfering vibrational elements of its own. But in 
the form of the phonograph and gramophone, the phonauto- 
graph has been brought to approximate mechanical perfection for 
the production of audible records, and the phonograph and 
gramophone grooves are therefore approximately perfect phys- 
ical records of speech vibrations on a microscopic scale. Various 
means of enlargement have been tried in the effort to render the 
sound grooves legible. 
Direct magnification^ of the sound groove has thus far proved 
unsatisfactory for the phonograph and impossible for the gramo- 
phone. In the phonograph groove the sinusoidal element is 
perpendicular to the surface and therefore in the line of sight, 
and hence disappears both in direct microscopic observation by 
the eye and in microphotographic enlargement. The gramo- 
phone groove is indeed sinusoidal in the plane of the record, but 
the length of the sinusoids is so great in comparison with their 
^ Scripture, Elements of Experimental Phonetics. New York, 1902, pp. 17-24. 
® Cf. Marichelle, La parole d!apres le trace du phonographe. Paris, 1897. 
See also Boeke in Pflueger's Archiv, 1891, p. 297. 
