SECT. IV.
ARTIC.
- 1 THe State of the Third Difficulty.
- 48
- 2 The Solution thereof in a Word.
- ibid.
- 3 Three praecedent positions briefly recognized, in order to the worthy profounding of the myste∣ry, of the Aers resisting Compression beyond a certain rate, or determinate proportion
- ibid.
- 4 The Aequiponderancy of the External Aer, pendent upon the surface of the Restagnant Mercury, in the vessel to the Cylindre of Mer∣cury residuous in the Tube, at the altitude of 27 digits: the cause of the Mercuries constant subsistence at that point.
- 49
- 5 A convenient simile, illustrating and enforcing the same.
- 50
- 6 The Remainder of the Difficulty; viz. Why the Aequilibrium of these two opposite weights, the Mercury and the Aer, is constant to the praecise altitude of 27 digits: removed.
- ibid.
- 7 Humane Perspicacity terminated in the exte∣rior parts of Nature, or simple Apparitions: which eluding our Cognition, frequently fall under no other comprehension, but that of rati∣onal Conjecture.
- ibid.
- 8 The constant subsistence of the Mercury at 27 digits, adscriptive rather to the Resistence of the Aer, then to any occult Quality in the Mer∣cury.
- 51
- 9 The Analogy betwixt the Absolute and Respe∣ctive Aequality of weights, of Quick-silver and Water, in the different altitudes of 27 digits and 32 feet.
- 52
- 10 The definite weights of the Mercury at 27 digits, and Water at 32 feet, in a Tube of the third part of a digit in diametre; found to be neer upon two pound, Paris weight.
- ibid.
- 11 Quaere, Why the Aequilibrium is constant to the same point of altitude in a Tube of a large concave, as well as in one of a small; when the force of the Depriment must be greater in the one, then the other.
- 53
- 12 The solution thereof by the appropriation of the same Cause, which makes the descent of two bodies, of different weights, aequivelox.
- ibid.