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EXPERIMENT XXXV. An Attempt to examin the Motions and Sensibility of the Cartesian Materia Subtilis, or the Aether, with a Pair of Bellows, which were made of a Bladder, in the exhausted Receiver.
IN order to try, whether there be any finer Substance than Air, in the exhausted Recei∣ver, we contriv'd to make a Pair of Bellows of a Bladder, whose Bases were Paste-board,* 1.1 the up∣per being cover'd with a Plate of Pewter, to which was fix'd a Leaden weight to press it down: Besides, over against the Nose of the Bel∣lows, in which the Neck of the Bladder ter∣minated, it was contriv'd, that the End of a Feather was fix'd so, that if any Subtle Matter were forc'd out of the Bellows, it should disco∣ver it self by moving that Feather.
The Bellows being thus provided, and the Pillars, to which the Feather is fastened, being joyn'd to the upper Basis of the Bellows, with Cement, we fix'd a Weight to the Lower Basis, and convey'd it into the Receiver;* 1.2 where we observ'd, upon the exhausting of the Receiver, that the Air in the Bellows rais'd up the upper Basis, together with it's Weight; and the Air rising out at the Vent, manifestly mov'd the Fea∣ther: But when the Receiver was quite ex∣hausted, and the Weight upon the Upper Basis depress'd it violently, we could not perceive that the Feather was in the least mov'd, and the like was observ'd upon repeating the Experi∣ment.