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TITLE XVI. Of the Air as the Medium of Sounds, and of Sounds and Noises in the Air, and Par∣ticularly Thunder; and of the Airs Ope∣ration on the Sounds of Bodies.
* 1.1UPon the Rising of several Tempests toge∣ther, the Sky seems covered over with Globes of Smoaky Clouds, the Air seeming black and Thick; and by and by incessant Light∣ning, with terrible loud Thunder breaks out; Ludolph's History of Aethiop. l. 1. c. 5.
A Viol String hath been Observed, upon Rainy weather, to sound half a Note sharper than before, and, I am told by the same Per∣son, that having kept false Strings in his Pockets for some time after, they became true ones; and the same Person hath Observ'd, that some Strings are apter to Receive a Tension, than others.