Results of experiments on the vibrations of pendulums with different suspending strings / by W.J. Frodsham.

  • Frodsham, William James, 1778-1850.
Date:
[1839]
Catalogue details

Licence: Public Domain Mark

Credit: Results of experiments on the vibrations of pendulums with different suspending strings / by W.J. Frodsham. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    and if this part of the apparatus had served only to attach the rod and spring more firmly toge- ther, and prevent any wavering motion of the pendulum, it would have rendered an important service. This, however, was but a secondary and incidental effect of its application. The piece, which I have so named, is a brass tube about five inches long, fitting the pendu- lum rod very nicely, and slit to form a spring for about an inch at the bottom, so as to slide rather stiffly on the rod. At the upper end of the tube is a clip, which is made to embrace the suspending spring firmly by means of two screws; so that after the pendulum has been brought to the proper length by the adjusting nut at the lower end of the rod, the length of the acting part of the suspending spring may be varied at pleasure, without in the least altering the length of the pendulum, by merely sliding the isochronal piece up or down the rod, and tightening the screws of the clip. I also provided five springs of different degrees of strength, and a silken string, by which, in the first experiments, the pendulum was suspended. The pendulum used was an uncompensated one, but in each experiment it was adjusted to nearly the proper length for mean time. Commencing with the silken thread, or rather two parallel threads, one behind the other, I suspended the pendulum within the case of a clock, perfectly detached from the works, no maintaining power being applied. Each degree of the scale on which the arcs of vibration were noted, was nearly -8 of an inch in length, and a degree was subdivided into twenty equal parts. I drew the bob aside 2°, and leaving it to vibrate by its own gravity, I found the arc of vibration was reduced from 2° to 1°, and from 1° to |°, in the times noted as under: Arc of vibration from 2° to 1° in 20m. 15 s. Do. do. 1 to ^ 23 6 On repeating the experiment, the results were— Arc of vibration from 2° to 1° in 21m. Os. Do. do. 1 to i 24m. Os. Drawing the pendulum aside 1°, I found from five successive trials that the arc of vibration was reduced to half a degree in the times following :