Physico-mechanical experiments on various subjects, containing an account of several surprizing phaenomena touching light and electricity. Producible on the attrition of bodies. With many other remarkable appearances, not before observ'd. Together with the explanations of all the machines, (the figures of which are curiously engrav'd on copper) and other apparatus us'd in making the experiments / By F. Hauksbee, F.R.S.

  • Hauksbee, Francis, 1666-1713.
Date:
1709
Catalogue details

Licence: Public Domain Mark

Credit: Physico-mechanical experiments on various subjects, containing an account of several surprizing phaenomena touching light and electricity. Producible on the attrition of bodies. With many other remarkable appearances, not before observ'd. Together with the explanations of all the machines, (the figures of which are curiously engrav'd on copper) and other apparatus us'd in making the experiments / By F. Hauksbee, F.R.S. Source: Wellcome Collection.

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    [ 193 ] are fix'd; the Threads ought to form themfefves into st fort of conical Surface; or rather the Surface of a Trunk of a Cone, whofe Vertex would be fome point in the Axis of the Globe or Cylinder; were the difcharge of EleCtrical Matter every way equable and uniform. And w.e find it matter of Fact, that the Threads did actually form tbem- felves into this fort of Figure. So that if there were two Hoops of Threads, plac’d one on one fide, and t’other of the other fide the Plane of Attrition, there would be two Curti-cone Surfaces form’d ; of which the more Acute would be that which is farthefi from the Plane of Attrition; and the more Obtufe, that which is nearefi thereto. For when the Plane of Attrition, and the Plane wherein the Threads are plac'd, do co-incide; then the Conic Surface is chang’d into the Area of a Circle: becaufe then the Threads lie all in one and the fame Plane. Thus much concerning the Electricity. I would now fubjoyn fome few things concerning the Lights produc’d in thefe Experiments. Prop. i. Tho’ the Electrical Quality neceffarilyrequir'd the prefence both.of the External and Internal Air, in order to its jhewing ilfe'f; yet the Light requir’d the prefence but of one of ’em, viz,, either the inward or the outward Air, in order to its appearance. For either a Glafs Globe full of Air, rubb’d in Vacuo ^ •or with its Air exhaufed, and rubb’d in Pleno, would either way produce a very confderable Light. • Prop. <2. There feems therefore tobe^z real difference between the Eleffrical and Luminous Effluvia ( at leaft in fome cafes :) For by the ’foregoing Prop. thefe Qualities require different Circumflances with refpect to the Cir¬ cumjacent Medium, in order to their difcovering them- felves* And more than that; a.ffronger Attrition, which