reasons than one; which, doubtless, will
appear very satisfactory to Intelligent _Readers_.
Wherefore, instead of the those _Paschalian_ Experiments, there is in this
_Treatise_ deliver'd a far more Expeditious way, to make out, _not only_
most of the _Conclusions_, agreed on these two Authors, _but_ others also,
that M _Paschall_ mentions not: and that with so much more ease and
clearness, that persons, but ordinarily versed in the common principles of
_Hydrostaticks_, may readily apprehend, what is deliver'd, if they will but
bring with them a due Attention, and Minds disposed to prefer Reason and
Experience to Vulgar opinions and Authors.
It not being our _Authors_ present Task, to deliver a Body of
_Hydrostaticks_, but only some _Paradoxes_, which he conceives to be
proveable by his New way of making them out, he delivers them in as many
distinct Propositions; after each of which, he endeavours, in a Proof, or
an Explication, to show, both that it is true, and why it ought to be so.
The _Paradoxes_ themselves (after a premised _Postulatum_) are these:
1. That in Water, and other Fluids, the Lower parts are pressed by the
Upper.
2. That a lighter Fluid may gravitate or weigh upon a heavier.
3. That, if a Body, contiguous to the Water, be altogether, or in part,
lower than the highest level of the said Water, the lower part of the Body
will be pressed upward by the Water, that touches it beneath.
4. That in the Ascension of Water in Pumps, &c. there needs nothing to
raise the Water, but a Competent weight of an External Fluid.
5. That the pressure of an External Fluid is able to keep an Heterogeneous
Liquor suspended at the same height in several Pipes, though these Pipes be
of very different Diameters.
{175}
6. If a Body be placed under Water, with its uppermost Surface parallel to
the Horizon; how much Water soever there may be on this or that side above
the Body, the direct pressure susteined by the Body (for we now consider
not the Lateral nor the Recoyling pressure, to which the Body may be
exposed, if quite environed with Water) is no more, than that of a Column
of water, having Horizontal Superficies of the Body for its Basis, and the
Perpendicular depth of the Water for its height.
And so likewise,
If the Water, that leans upon the Body, be contained in Pipes open at both
ends, the pressure of the Water is to be estimated by the weight of a
pillar of Water, whose Basis is equal to
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