16th Day. That Fluids gravitate _in proprio loco_, the upper Parts
continually pressing upon the lower: That this Pressure is not only
propagated Downwards, but even Upwards, and Sideways, according to all
possible Directions; That a lighter Fluid may gravitate upon a heavier,
and an heavier upon a lighter; That a Fluid may sustain a Body heavier _in
Specie_ than it self, and even raise it up; That a Fluid may detain a Body
lighter _in Specie_ than it self, and even depress it. A general
Experiment to prove, that a competent Pressure of a Fluid may produce the
remarkable Phænomena of the Torricellian Tube, the Pump, Syringe, Syphon,
polished Plates, and other Effects of the like Nature.
17th—That Fluids press according to their perpendicular Altitudes,
whatever be their Quantities, or however the containing Vessels be
figured. The exact Estimate of all manner of Pressures. That the Velocity
and Quantity of Fluids running out at a given Hole, is in the subduplicate
Proportion of their perpendicular Altitudes. Several Sorts of Pumps. Of
the sinking and floating of Bodies immers'd in Fluids; their relative
Gravities and Levities; their Situations and Positions. The Phænomena of
Glass Bubbles and Images accounted for.
18th—An Instrument to find out the Specifick Gravity of all Liquors. The
Hydrostatical Balance explain'd, with the Methods of determining the
Specifick Gravities of all Sorts of Bodies, whether Solid or Fluid,
thereby. The Praxis of the Hydrostatical Balance, whereby the Specifick
Gravities of several particular Bodies are actually found out. Some
Account of the various Uses of such Enquiries.
PNEUMATICKS _illustrated by Experiments for the most part Tubular,
being such as were wont to be made before the Air-Pump was invented._
19th Day. The several Phænomena of the Torricellian Experiment exhibited
and explained. Other Experiments of the like Nature, with Fluids variously
combin'd. Several Sorts of Barometers, Thermometers, and Hygroscopes. The
Pressure of the Air shewn by Experiment to be different at different
Altitudes from the Surface of the Earth.
20th—The Density and Spring of the Air proved by several ways to be as the
Force which compresses it, and reciprocally as the Spaces into which it is
compress'd. From hence an Enquiry is made into the Limits and State of the
Atmosphere.
21st—The Effects of the Weight and Spring of the Air in Syringes, Pumps,
Siphons, polished Plates, Cupping-Glasses, Suction: Respiration explained
by artificial Lungs; That the Air may be so disorder'd by a violent
Impulse, as to require Time to recover its Strength and Elasticity again.
_The more known Properties of the Air established by the Air-Pump, and
other Engines._
22d Day. The Air-Pump; the Instruments for Condensing and Transferring of
Air; their Fabrick, Operation, and Gages explained.
23d—A Parcel of Air weighed in the Balance; its Specifick Gravity to that
of Water determined thereby; an artificial Storm, shewing that high Winds
may make the Barometer sink much and suddenly.
24th—The Weight, Pressure, and Spring of the Air prov'd several ways; by
the Sense of Feeling; by breaking Glass Vials; the Phænomena of Bladders,
Glass-bubbles, Fountains; the Gardiner's Watering-Pot; the Diving-Bell,
_&c._
25th—The Torricellian Tube _in Vacuo_; Quicksilver raised to the usual
Height of the Weather-Glass, by the bare Spring of a little included Air;
_Otto Gerick_'s Hemispheres; and that dense Air has the same Advantage
over common Air, as that has over a _Vacuum_.
The Ebullition of Liquors _in Vacuo_; the Quantity of Air contain'd in
them; the Sustentation of Fumes and Vapours; the Descent of Bodies _in
Vacuo_.
_The more hidden Properties of the Air consider'd by the help of the like
Engines._
26th Day. The Influence of the Air examin'd as to the Causes of Magnetism;
the Elasticity of Springs; the Cohæsion of the Parts of Matter; the
Sphericity of the Drops of Fluids; the Ascent of Liquors in capillary
Tubes, and between Glass-Planes in the Curve of the Hyperbola, both by the
Attractive and Repulsive Power of the Glass.
27th—The Influence of the Air, as to Sounds, Fire, and Flame; the
Consumption of Fuel; the firing of Gunpowder; the Effects of rarified,
condensed, and burnt Air upon the Life of Animals.
28th—A Piece of Phosphorus _in Vacuo_; new Experiments concerning the
Mercurial Phosphori; Experiments concerning the Electricity of Bodies.
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_Every SUBSCRIBER is to pay Three Guineas; One Guinea at the Time of
Subscription, and the Remainder, the First Day of the Course._
SUBSCRIPTIONS _are taken in at Mr. Whiston's, in Great Russel-Street; and
at Mr. Hauksbee's, in Crane-Court in Fleetstreet; where the Course is to
be perform'd._
Advertisement.
Air-Pumps, or Engines for Exhausting the Air from proper Vessels, with all
their Appurtenances; whereby the various Properties and Uses of that Fluid
are discover'd and demonstrated by undeniable Experiments. Engines for the
Compression of the Air: Fountains, in which the Water, or other Liquor, is
made to ascend by the Force of the Air's Spring. Syringes and Blow-Pipes,
with Valves for Anatomical Injections. Hydrostatical Balances, for
determining the Specifick Gravity of Fluids and Solids. The Engine and
Glasses for the New Way of Cupping without Fire. Scarificators, which at
once make either 10, 13, or 16 Incisions. Weather-Glasses of all Sorts, as
Barometers, Thermometers, _&c._ Reflecting Telescopes, by which in so
short a Length as Six Feet, all that has hitherto been discovered in the
Heavens (by the longest Telescopes of the common Construction) may be
observed.
All the above-mention'd Instruments, according to their Latest and Best
Improvements, are made and sold by FRANCIS HAUKSBEE, in _Crane-Court_ in
_Fleetstreet, London_.
[[Mechanicks Plate I. ― Sutton Nicholls sculp:]]
1
MECHANICKS.
An Explication of the First PLATE.
Figure. 1. This belongs to _Galilæo's_ famous Demonstration of the
Velocities and Times of Bodies descending by an uniform Force, such is
that of Gravity here below: And shews that they will ever fall in equal
Times, 1, 2, 3, 4, _&c._ according to the odd Numbers, 1, 3, 5, 7, _&c._
or the Trapezia B C D E, D E F G, F G H I, _&c._ and by consequence, that
their Velocity will increase uniformly in Proportion to the Lines B C,
D E, F G, H I, _&c._ or to the Times of Descent. And that the entire Lines
of their Descent will be as the Triangles A B C, A D E, A F G, A H I,
_&c._ or as the Squares of those Times, 1, 4, 9, 16, _&c._
_Fig. 2._ This is a strong Balance for an Experiment to prove the former
Proposition, by shewing that any Bullet or Ball, when it falls from four
Times the Height, has twice, from nine Times the Height has thrice its
former Velocity or Force; and will accordingly raise a double or triple
Weight in the opposite Scale, to the same Height, and no more; and so for
ever.
_Fig. 3._ This shews how Bodies upon an inclin'd Plane will _slide_, if
the Perpendicular through the Center of their Gravity falls _within_; and
will _rowl_, if that Perpendicular fall _without_ their common Section.
_Fig. 4._ This shews that an oblique Body will stand, if the Perpendicular
through its Center of Gravity cut the Base; and that it will fall, if it
cut not the Base: As accordingly we stand when the Perpendicular through
the Center of Gravity of our Bodies falls within the Base of our Feet; and
we are ready to tumble when it falls without the same.
_Fig. 5._ This is a Conick Rhombus, or two right Cones, with a common
Base, rowling upwards to Appearance, or from E towards F and G: Which
Points are set higher by Screws than the Point E. But so that the
Declivity from C towards A and B is greater than the Aclivity from E
towards F and G. Whence it is plain, that the Axis and Center of Gravity
do really descend all the Way.
_Fig. 6._ Is a Balance, in an horizontal Posture, with weights at
Distances from the Center reciprocally proportional to themselves; and
thereby _in Æquilibrio_.
_Fig. 7. and 8._ Are two other Balances in an horizontal Posture, with
several Weights on each Side, so adjusted, that the Sum of the Motion on
one Side, made by multiplying each Weight by its Velocity, or Distance
from the Center, and so added together, is equal to that on the other: And
so all still _in Æquilibrio_.
_Fig. 9._ Belongs to the Laws of Motion, in the Collision of Bodies to be
tried with Pendulums, or otherwise, both as to Elastical Bodies, and to
those which are not Elastical.
_Fig. 10._ Belongs to that Famous and Fundamental Law of Motion, that if a
Body be impell'd by two distinct Forces in an Proportion, it will in the
same Time move along the Diagonal of that Parallelogram, whose Sides would
have been describ'd by those distinct Forces; and that accordingly all
Lines, in which Bodies move, be consider'd as Diagonals of Parallelograms;
and so may be resolved into those two Forces, which would have been
necessary for the distinct Motions along their two Sides respectively:
Which grand Law includes the Composition and Resolution of all Motions
whatsoever, and is of the greatest Use in Mechanical and Natural
Philosophy.
_Fig. 11._ Are two polite Plains inclined to one another, to shew that the
Descent down one Plain will elevate a Ball almost to an equal Height on
the other.
[[Plate II. ― Sutton Nicholls sculp:]]