Page:Researches on Irritability of Plants.djvu/142

same specimen, using the same stimulus but varying the mode of record—that is to say, the vibrator used in one case had been tuned to 50 vibrations per second, the length of the recorder being 12 cm. The speed of the recording-plate was in this case relatively slow. The result is shown in fig. 71. The other record in fig. 72 was taken immediately afterwards from the same specimen with a vibrator tuned to 100 double vibrations per second, the recording-plate

Figs. 71, 72.—Two successive records taken with the same leaf; upper with 50 D.V. recorder and slow-moving plate; lower with 100 D.V. recorder and faster-moving plate. Latent period in either case is .17 second, proving that value of L is unaffected by any peculiarity of the recorder.

moving at a faster rate. It will be seen from fig. 71 that the time-interval in the first case is represented by 8.5 spaces, each representing .02 second, therefore proving the latent period L to be .17 second. This, it should be mentioned, was an autumn specimen, in which the latent period is somewhat longer than in summer. In the second record, fig. 72, under its different speed and with the vibrator giving 100 vibrations per second—we find the intervening spaces to be 17. This gives the latent period as again