784 PROFESSOR JOHN G. M'KENDRICK 



DESCRIPTION OF PLATES. 



Plate I. 



[In Figs. 1-14 (except Figs. 3 and 6), the vertical length of the tracing represents ^ T * n sec -> an( ^ ^ ne 

 cylinder rotates from the bottom to the top of each tracing.] 



Fig. 1. Full organ, taken 40 feet from instrument. Portion of Mendelssohn's Wedding March. 



Fig. 2. Chords on violin. 



Fig. 3. Portion of a celloidin cast of cylinder on which was recorded a march by a military band. 



Fig. 4. Flute. 



Fig. 5. Tenor voice. 



Fig. 6. Violin, quick playing. 



Fig. 7. Piccolo. 



Fig. 8. Xylophone. 



Fig. 9. Tuning fork. 



Fig. 10. Tuning fork, 64 vibs. p. sec. (one long mark). 



Fig. 11. Tuning fork, 128 vibs. p. sec. (two marks). 



Fig. 12. Tuning fork, 256 vibs. p. sec. (four marks). 



Fig. 13. Tuning fork, 512 vibs. p. sec. (eight marks). 



Fig. 14. Tenor voice (second record). 



Fig. 15. Diagram of recording apparatus described in text. 



Fig. 16. Shows on a larger scale than in fig. 15 the recording arrangement. 



Fig. 17. Under surface of leaden weight to which recording lever was attached. 



Fig. 18. Facsimile of curves obtained from record of old English coach horn. 



Fig. 19. Facsimile of curves obtained from record of a military band. 



Note on Figs. 18 and 19. — These curves (3 inches of the tracing representing yoth sec. ; that is to 

 say, the curves in 3 inches were recorded on the cylinder of the phonograph in j^jth sec.) should be 

 examined with a magnifying glass. In the two upper lines of 18, note the uniform character of the 

 curves. In the third line the character of the curve alters. These are tracings of the marks produced 

 by the long-drawn-out, clear, piercing tones of the horn. In 18, the upper and lower lines show great 

 variety of curve form. The middle line shows no curves, and probably represents an interval of silence. 



Plate II. 



[Note. — Tracings in Figs. 1, 2, 3, and 4 to be read from right to left.] 



Fig. 1. Facsimile of the vibrations in the words " Tit for Tat." 



Fig. 2. Facsimile of the vibrations in the word " University." See description of next fig. 



Fig. 3. Facsimile of the vibrations in the words " Glasgow " and " University." The word " Glasgow " is in 

 the upper line, and it will be observed that the marker was raised a little to the left of the 

 beginning. The word " University " is in the lower line, " Univer " to the right, then a short 

 pause, and then the end of the word, " sity." 



Fig. 4. Facsimile of the vibrations in the word " Glasgow." 



Fig. 5. Tracings taken with the apparatus described in paragraph 24 of the paper. They are to be read 

 from left to right. They represent the variations in intensity of the notes and chords of a 

 military band. Each wave represents a note or chord, and the height of the wave indicates 

 the intensity. A length of one-quarter of an inch represents the impulses communicated from 

 the phonograph to the microphone in one quarter of a second, that is, in the time occupied by 

 half a revolution of the phonograph cylinder when the sound is reproduced. A careful 

 examination will show that portions of the music are repeated. See the uniform waves in 

 lines 3 and 6. These represent blows on an anvil, as produced in the "anvil chorus," of which 

 this is a reproduction. 



