3S 
April 5, 1878.] 531 |Frazer. 
Some Microscopical Observations of the Phonograph record. 
By PERSIFOR FRAZER, JR., A. M. 
(Read before the American Philosophical Society, April 5th, 1878.) 
As soon as the first wonder and delight at the performance of the phono- 
graph had commenced to subside, physicists immediately set about think- 
ing in what way this instrument could aid in their general researches. 
This wonder was very natural, and it was greatest among those most 
versed in acoustics ; for it was a curious question why, with all the elabor- 
ate and delicate apparatus in the world, with the profundity of its design- 
ers, and the ambition of its employers ; with the attention of mankind di- 
rected so long to the problem of producing inanimate articulate speech ; 
and after the production of a permanent record of the characters of the 
sound waves of human voice.upon smoked glass, no one had hit upon 
so simple an expedient for producing a record, which can be used to repro- 
duce the sound. 
The apparatus which Mr. Edison has employed is a cylinder covered 
with thin foil on which the blunted end of a needle or stylus impinges. The 
impression made by the point of the needle in the soft lead paper depends 
upon the path which that point was describing at the moment when the 
impression was made. By turning the cylinder with uniform motion so that 
the needle traverses a helical groove traced on its surface, at the same 
rate both when speaking and causing the instrument to speak; the 
point of the stylus will travel over the same or nearly the same path, and 
the motions transmitted by the point to the centre of the diaphragm will 
be nearly the same in kind (though feebler in force) as before. 
It was natural at once to think of investigating the forms left by the 
stylus in the soft lead foil under the microscope, and this has been done. 
The following remarks are oftered simply as a small contribution to an 
investigation which is clearly destined to occupy the minds of some of the 
ablest physicists for a long time to come. 
By the kindness of Dr. Plush (Superintendent of the Philadelphia 
Local Telegraph Company), the following experiments were tried on 
his apparatus: After repeating the vowels and dipthongs A (ah), E 
(ay), I (ee), O (oh), U (00), OI, OW, 4 (as in hat), é (as in bed), i (as 
in him), 6 (asin Tobias), U (as in put), frequently enough to produce as 
uniform a result as possible, Dr. Plush spoke them into the mouth-piece, 
leaving spaces between each vowel and the end of the series ; so that there 
was no difficulty in picking out the different sound-records. 
This record was then allowed to speak (its pronunciation being carefully 
noted and where necessary improved by another trial) two other records 
were added, thus filling up one sheet of the foil or matrix. When the 
articulation was deemed satisfactory the following records after having 
been made, were not subjected to the touch of the stylus for fear of oblit- 
erating or partially obscuring them. 
These matrices were mounted on slips of glass, and were carefully exam- 
