Monday, November 23, 2020
Themes echo more loudly in fog
Since I'm in Connecting Themes mode today:
Here's more from Tyndall's textbook on Sound, cited in previous item on Trinity House acoustical research at Lizard Point.
Tyndall was disproving the commonly held THEORY that fog absorbed sound because it absorbed light. This should have been obvious to any alert observer. You can hear all sorts of distant sounds in fog. Apparently it wasn't obvious to other scientists at the time.
During the exceedingly dense and dripping fog of January 22 I placed myself near the same railings and heard every stroke of the bell. On the same day an assistant at the end of the Serpentine, when the fog was densest, heard the Westminster bell striking loudly eleven. Towards evening this fog began to melt away, and at 6 o'clock I went to the end of the Serpentine to observe the effect of the optical clearing of the atmosphere upon the sound. Not one of the strokes reached me. At 9 o'clock and at 10 o'clock my able assistant Mr. COTTRELL was in the same position, and on both occasions failed to hear a single stroke of the bell. It was a case precisely similar to that of December 13, when the dissolution of the fog was accompanied by a decided acoustic thickening of the air.Cottrell. Fog. Sounds familiar.... Yes. The same Cottrell later improved Lodge's precipitator to purify fog and smoke. Did he have an epiphany about fog while working for Tyndall?
Labels: Carver, Trinity House
¶ 2:56 PM
