The height of the The Expansion The height of The strength Cylinder of Mercury, of the Air. the Mercury of the Elater that, together with that counter- of the expanded the Elater of the ballanc’d the Air. included Air, Atmosphere. ballanced the pressure of the Atmosphere. ---------- ---------- ---------- ---------- 00 01 30 30 02 01¹⁄₁₆ 30 28 04 01⅐ 30 26 06 01²⁄₉ 30 24 08 01⅓ 30 22 10 01½ 30 20 12 01⅔ 30 18 14 01⅚ 30 16 16 02²⁄₂₇ 30 14 18 02⁴⁄₉ 30 12 20 03 30 10 22 03⁷⁄₉ 30 8 24 05⁷⁄₁₈ 30 6 25 06⅔ 30 5 26 08½ 30 4 26¼ 09½ 30 3¾ 26½ 10¾ 30 3½ 26¾ 13 30 3¼ 27 15½ 30 3 I had several other Tables of my Observations, and Calculations, which I then made; but it being above a twelve month since I made them; and by that means having forgot many circumstances and particulars, I was resolved to make them over once again, which I did _August_ the second 1661. with the very same Tube which I used the year before, when I first made the Experiment (for it being a very good one, I had carefully preserv’d it:) And after having tryed it over and over again; and being not well satisfied of some particulars, I, at last, having put all things in very good order, and being as attentive, and observant, as possibly I could, of every circumstance requisite to be taken notice of, did register my several Observations in this following Table. In the making of which, I did not exactly follow the method that I had used at first; but, having lately heard of Mr. _Townly_’s _Hypothesis_, I shap’d my course in such sort, as would be most convenient for the examination of that _Hypothesis_; the event of which you have in the latter part of the last Table. The other Experiment was, to find what degrees of force were requisite to compress, or condense, the Air into such or such a bulk.