A continuation of new experiments physico-mechanical, touching the spring and weight of the air and their effects. The I. part whereto is annext a short discourse of the atmospheres of consistent bodies / written by way of letter to the right honourable the Lord Clifford and Dungarvan by the honourable Robert Boyle ...

Postscript.

SInce the last recited Experiment was made, and written, find∣ing some of our Instruments to be in better order than they were when that Tryal was made, vve thought fit to endeavour by that which follows, to repair an omission or two, that former∣ly we could not well avoid.

Having then caus'd such a Glass-pipe, as has been lately men∣tioned, to be vvell cemented on to the Syringe, (vvhose Sucker did now move more easily, and yet fill the Barrel more exactly, than before,) I order'd (being to be absent for a while my self) that the Pipe should be fill'd with spirit of Wine tincted with Coche∣neel, that the liquor and its motions might be the better discern'd, and that the Pipe being fill'd, that Air might be excluded, which vvould else be harboured in the Pipe, (which Caution was omit∣ted in the foregoing Experiment.) And this the Person, to whom I committed it, affirm'd to have been carefully done, though when he inverted the Pipe thus fill'd into the rest of the red Liquor, that was put into a Viol, he could not possibly do it so well, but that a bubble of Air got into the Pipe, and took up some (though but a litle) room there. By that time, I was call'd upon, to see

the Event of the Tryal, and could come to look upon it, the Re∣ceiver was almost quite exhausted; vvherefore after I had made the pumping be continued a litle longer, and perceived that the tincted spirit was fallen down out of the Pipe, and that which lay in the Viol seem'd almost to boyl at the top, by reason of the e∣mersion of numerous Bubbles, I caus'd the Sucker to be, by the help of the Turning-key, drawn up (by our aestimate) about two inches and a half, notwithstanding which vve could not perceive the spirit of Wine to rise in the Pipe, (though the Pumping were before left off.) For vvhich reason I order'd the Air to be let in very leisurely, upon which vve could plainly see that the red spi∣rit was quickly driven up to the top of the Pipe, and that it was so likewise into the Cavity of the Barrel, appeared, when the Re∣ceiver was removed, by the small Quantity of Liquor that re∣mained in the viol, and the plenty of it which came out of the Syringe.

NB. That if I had not vvanted dexterous Artificers, to work according to a Contrivance I had design'd, I had attempted to imitate, by the help of the bare Spring of the Air, such Experi∣ments, as in the lately recited Tryals vvere made to succeed, by the help of the Pressure exercis'd by the Air upon the account of its Weight.