as to caufe no fenfible Error, the Times are marked by Sounds, and the ExperiSpaces defcribed by an Index. ments for illuftrating of central Forces. A Glafs Globe mounted on an Axis fo that it may be turned round the Theory with any Degree of Velocity. This Machine fhews the Effects of central Forces on Fluids of different Specific Gravities, and on Solids, which circulate in the fame Medium. A terreftrial Globe which turns on its Axis with any given Velocity. The Surface of this Globe is flexible, its Concavity is filled with a Matter fomewhat fluid, and is fo contrived, that its two Poles are capable of moving towards each other, fo that by turning the Globe, the centrifugal Force raifes the Equator of the Globe, and fhews the Figure which modern Difcoveries attribute to the Earth. A graduated Rule adapted to a Glafs Tube within which a fmall Cylinder is put in Motion. Second, A Plane upon which two Bodies defcribe in the fame Time unequal Spaces. Third, A Globe of Cork of of three Inches Diameter, with a Ball of Lead of the fame Weight. By the Affiftance of the three laft Articles are explained the Properties of Motion, viz. Direction, Velocity, Quantity of Motion, &c. A fmall Cyftern divided into two equal Parts by a Partition upon which is mounted a double Pendulum, fhewing in what Ratio different Mediums exert their Refiftance. A Machine with which is demonftrated the Doctrine of the Collifion Experiof Bodies. ments for illuftr. ting The Parts of this Machine are made with the utmoft Care, the Maffes the Doctrine are in given Proportions, and the Effects remain visible after the Experiment by the Means of an Index. A CHRONOMETER or Inftrument for measuring fmall Intervals of Time. The Pendulum which conflitutes the principal Part of this Inftrument may be lengthened or fhortened according to a Scale accurately divided for the vibrating Minutes, Seconds, Thirds, and the different Times of Mufick. A fmall Billiard-Table with its Appendages. The Appendages of this Machine are Hammers Jufpended in fuch a Manner, that the Quantity of Motion may be regulated by the Velocity, or by the Mafs, and fo as to exhibit the Motion of a Body impelled by Forces acting in different Directions, and known Proportions. of the Colli fion of Bodies. ments for il A Machine for fhewing the Motion of a Body which receives at the Experifame Time an Impulse in a perpendicular and horizontal Direction. luftrating Another Machine for fhewing the Motion produced by two Forces acting on a Body in Directions forming an Angle, but which conftantly remain in the fame Ratio. A Machine for fhewing the Acceleration of Bodies which fall freely. Secondly, a Kind of Balance for making the fame Kind of Experiments. Thefe two laft Machines not only fhew that the Motion of Bodies is accelerated in their Defcent, but also renders fenfible the Law of this Acceleration. the Compoft tion and Re folution of For.es. Experiments for illuftrating the Doctrine of the Motion of heavy Bodies. Experi ments for illuftrating the Nature ties of the A Machine for fhewing the Line a Body defcribes when abandoned to its Weight after having received an Impulsion in an horizontal Direction. A Machine for fhewing the Motion of a Body abandoned to its Weight after having received an Impulfion upwards, but oblique to the Horizon. As the Curve which refults from this Motion depends on the Obliquity of the Direction, the Machine is conftructed fo that the Degree of Obliquity may be varied at will. A Machine which ferves to compare the Velocity of a Body which in its Discent describes a Cycloyd with that of another tending to the fame Point along an inclined Plane. A Machine for fhewing in what Ratio several Forces act on the fame Body. A Machine for explaining the Laws of Elafticity. Two Cones joined together by their Bafes, and which afcend an inclined Plane. 2d. A Cylindar which ascends an inclined Plane. Thofe two Machines ferve for proving experimentally, that a Body canand Proper- not remain at rest when its Centre of Gravity is not fupported. The Plane on which the double Cone moves is formed of two Rulers inclined to each other and to the Horizon, and this double Inclination may be varied at pleafure as the Experiment may require. Center of Gravity Experi ments for A fmall Carriage with its Appendages. This Model with the Parts which accompany it, fhews the refpective Advantages of broad or narrow Wheels, of large or small ones, and what renders Carriages more or lefs liable to be overturned. A Machine for fhewing the Properties of the inclined Plane. This Machine is fo conftructed that the Inclination of the Plane may illuftrating be varied from the horizontal Line to the vertical, and that the Power may act in any defired Direction. the Theory of fimple Machines, the inclined Wedge, the Lever. A Machine for fhewing the Nature and Properties of the Wedge. What forms the Wedge in this Machine are two Planes inclined to each other, the Degree of Inclination can be varied at pleasure, as alfo the Power, the Weight and the Bafe of the Wedge. A Screw which can be taken to Pieces to fhew the Principles of its Construction. A Machine for fhewing the Nature of the three Species of Levers. A large Beam accurately divided, mounted on a Foot, for fhewing the Properties of the Lever. The Power, the Weight, and the Prop or Fulcrum are moveable, and may be eafily placed Jo as to be to each other in any given Proportions. Two Figures in Eqilibrio on a Pivot, for fhewing the Art of Chord or Wire-dancing. A large Brafs Pully, in which the Circumference and the diametral Lines have only been left, in order to fhew that the Pully may be confidered as an Affemblage of Levers of the first Species. Proof At the Back of the Supporter, there is fixed a Lever of the Jame Species with thofe which conflitute the Diameters of the Pully, to ferve as a by the Application of the fame Power and Weight. A Pully whofe Axis is moveable in a perpendicular Direction, and which ferves to fhew the Action of the Power, and of the Weight on this Axis, in different Cafes. A Block with two Pullies. 2d. A Block with four Pullies; another Block whofe Pullies are fixed on the fame Axis. All thofe combined Pullies are of Metal or Ivory, turned on their Axis with great Precision, and all possible Care has been taken to diminish the Friction. An Affemblage of feveral Toothed Wheels and Pinions, for fhewing Models for that both the one and the other like the Pullies, may be confidered as Levers. At the Back of the Supporter, are fixed an Affemblage of Levers which correfpond in the fame Manner as the Diameters of the Wheels on the other Side, to ferve as a Proof by the Application of the fame Power and Weight. fhewing the Application of fimple Machines in compounded the more ones. The Capitan, the A Model of Archimedes's Screw, whofe Effects are rendered fenfible by Pile-driver, the Motion of feveral fmall Balls of Ivory, which are raised fucceffively. Wind-mills, A Model of an Endlefs Screw, which drives an Axis. 2d. A Model Water-mills, of a Prefs. 3d. A Model of a Capftan. 4th. A Model of a Crane. 5th. A Model of an Engine for driving Piles. A Jack, of a particular Conftruction, for raifing great Weights. A common Balance, for fhewing the Defects to which this Machine is liable, and how they may be remedied. A large Roman Balance, contrived for making the Experiments of Sandorius. This Machine is fo conftructed, that a Perfon may weigh bimself without the Affiftance of another. A Model of a Screen for winnowing Corn by the Means of an artificial Wind, and feveral Screens of a particular Conftruction. A Model of a Saw for cuting at the fame Time feveral Flints, Agates, Cornelians, &c. and at one Stroke, to form Tables for Snuff-Boxes, and other Works. An horizontal 'Turning Leath, adapted for grinding Glaffes for Telescopes, Microscopes, &c. A Model of a common Wind-Mill. 2d. A Model of a Polish WindMill. 3d. A Model of a Water-Mill for extracting Oil. 4th. A Model of a Water-Mill for winnowing and grinding Corn, drawing up the Sacks, and boulting the Flour. &c. Experiments for fhewing the As all thofe Models are intended to fhew the Application of fimple Machines in the more compounded ones, Care has been taken to leave exposed or to cover with Glafs, the Pieces defined for Motion, and the Proportion of the Parts have been carefully obferved. A Machine for fhewing the Effects of Friction, in Machines more correct, and of a more extenfive Ufe than any hitherto invented. SECOND CLASS.. Machines for making Experiments on the Motion, Gravity and Equilibrium of Fluids. II. A large Cistern lined with Lead, with a Cock to it, which ferves for making feveral hydroftatical Experiments. Two large cylindrical Glaffes mounted on a common Base, between which is erected a Stem which carries a Beam of a Balance. This Machine is very commodious in feveral Operations which regard the Weight or Equilibrium of Fluids. A fmall Bottle with a Glafs Stepper, and heavier in this State than Properties of a Quantity of Water of the fame Bulk. Fluids. Experiments for fhewing the Preffure of Fluids upon toms and A Glass Tube, a Part of which rifes perpendicularly, and the other forms feveral Flexions for fhewing the Height of Fluids in Veffels which have a Communication with each other. A fmall Barrel with a Cock to it, and a bent Tube which ferves for demonftrating the fame Principle, with fome curious Applications. A Glafs Veffel, partly filled with a coloured Fluid, to which is adjufted a large Glafs Tube, and a fmall fucking Pump, which ferves to thew that Columns of the fame Fluid are of the fame specific Gravity. A long Tube of Glafs with a Cock at the lower Extremity, and mounted on a graduated Ruler, to which is adjusted a Pendulum which beats Seconds. This Machine ferves to fhew bow the Parts of a Fluid prefs each other, and in what Ratio the Effluxes thereof are performed. A Bladder filled with a coloured Fluid, to which is fitted a Glafs Tube, which ferves to fhew that Fluids exert their Preffure in all Directions. A Veffel whose Bottom burfts by the Preffure of a small Quantity of a Fluid. A large Machine, which ferves to fhew the Preffure of Fluids on the Bottoms and Sides of Veffels which contain them. This Machine confifts of feveral fine Veffels of Glafs, which are adthe the Bot- jufted fucceffively on a common Bafe, the Pifton which ferves as a Bottom, Sides of the is Jufficiently moveable as not to cause any fenfible Error by Friction, the Vellels that Columns of the Fluid remain always at the fame Height, and the Power acts uniformly. contain them. An Hydrometer with fix fmall cylindrical Vafes, which are filled with different Fluids. Two fmall Cruets, mounted each on a Pedeftal, which ferve for the Experiments by which Water is apparently changed into Wine, and Wine into Water. Two Vafes of different Forms, which ferve to make a heavier Fluid affume the Place of a lighter in the fame Veffel, without mixing. A Veffel perfectly cylindrical of Copper, with a Solid of the fame ExperiMetal, and of the fame Figure, which fills it exactly, for fhewing how ments for illuftrating much a Body immerfed in a Fluid, lofes of its Weight. the Action A Vafe of Glass fufpended to the Arm of a Balance, for making Ex- of Fluids periments of the fame Kind. Two Balls, one of Ivory, and the other of Lead of the fame Weight, prepared to be fufpended to the Arm of the Balance just mentioned, for fhewing, that what a Body lofes of its Weight when immerfed in a Fluid, is proportional to its Bulk. A cylindrical Vafe of Glafs filled with Water, with feveral human Figures of Enamel, of which some are lighter and the others heavier than a like Portion of the Fluid in which they are immersed. A Machine for fhewing that the relative Gravity of a Body immerfed in a Fluid, is changed when the Fluid is condensed or rarified. This Machine renders palpable by a very quick Operation, the Effects which the different Temperatures of the Air produce in the different Kinds of Thermometers hitherto invented. A human Figure of Enamel, which is made to move in Water by A Model of the Diving Bell, and the Appurtenances of a Diver. upon Bodies immeried in them. A Model of a curious Machine for raifing up Veffels that are funk. A Water Level. A fimple Syphon. 2d. A Fountain Syphon mounted on a Pedestal. 3d. A Syphon with its Vafe to be placed in Vacuo. Experi4th. A double Syphon. 5th. A Syphon whofe Branches are moveable ments for by the Means of a Joint. 6th. Tantalus's Cup. 7th. A large Syphon illuftrating whose Branches are moveable, neceffary in Experiments made with the produced by Air-Pump. All thofe different Species of Syphons are of Glafs, that the Motion of the Fluids may be more easily perceived. A Model of a Sucking-Pump. 2d. A Model of a Lifting-Pump. 3d. A Model of a Sucking and Lifting Pump. 4th. A Model of the Engine under London-Bridge, that raifes Water by Forcing-Pumps, the Effect the Preffure, &c. of Fluids. |