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"Orthohombric. Usually in tabular diamond-shaped crystals, formed by a short prism terminated by low brachydomes. The brachydomes are usually striated parallel to the brachy-axis. Twinned at times, giving stellate groups; the different individuals of the twin groups being distinguished from each other by the direction of the striations upon them." — Ford, 1912

Arsenopyrite

"Orthohombric. Usually in tabular diamond-shaped crystals, formed by a short prism terminated by low…

"Orthorhombic. Crystals resemble closely those of barite. Commonly tabular parallel to the base or prismatic parallel to the brachy- or macro-axis with prominent development of the domes. Crystals which are elongated parallel to the brachy-axis are frequently terminated in front by four faces in nearly equal development, consisting of 2 prism faces and 2 of the macrodome." — Ford, 1912

Celestite

"Orthorhombic. Crystals resemble closely those of barite. Commonly tabular parallel to the base or prismatic…

"A regular hexahedron: a solid figure bounded by 6 equal squares." — Williams, 1889

Cube

"A regular hexahedron: a solid figure bounded by 6 equal squares." — Williams, 1889

"Having equal sides." — Williams, 1889

Equilateral triangle

"Having equal sides." — Williams, 1889

"The essential parts of an ordinary Wimshurst machine, are two ordinary drums. On each plate are fixed a large number of strips of conducting material which are equal in size and are equally spaced, radially if on a plate, and circumferentially if on a drum." — Hawkins, 1917

Wimshurst Electric Machine

"The essential parts of an ordinary Wimshurst machine, are two ordinary drums. On each plate are fixed…

Nicholson's Hydrometer, consists of a hollow cylinder of metal with conical ends, terminated above by a very thin rod bearing a small dish, and carrying at its lower end a kind of basket. This latter is of such weight that when the instrument is immersed in water a weight of 100 grammes must be placed in the dish above in order to sink the apparatus as far as a certain mark on the rod. By the principle of Archimedes, the weight of the instrument, together with the 100 grammes which it carries, is equal to the weight of the water displaced. Now, let the instrument be placed in another liquid, and the weights in the dish above be altered until they are just sufficient to make the instrument be placed in another liquid, and the weights in the dish above be altered until they are just sufficient to make the instrument sink to the mark on the rod.

Hydrometer

Nicholson's Hydrometer, consists of a hollow cylinder of metal with conical ends, terminated above by…

Nicholson's Hydrometer, consists of a hollow cylinder of metal with conical ends, terminated above by a very thin rod bearing a small dish, and carrying at its lower end a kind of basket. This latter is of such weight that when the instrument is immersed in water a weight of 100 grammes must be placed in the dish above in order to sink the apparatus as far as a certain mark on the rod. By the principle of Archimedes, the weight of the instrument, together with the 100 grammes which it carries, is equal to the weight of the water displaced. Now, let the instrument be placed in another liquid, and the weights in the dish above be altered until they are just sufficient to make the instrument be placed in another liquid, and the weights in the dish above be altered until they are just sufficient to make the instrument sink to the mark on the rod.

Hydrometer

Nicholson's Hydrometer, consists of a hollow cylinder of metal with conical ends, terminated above by…

A rhomboid is a parallelogam whose opposite sides are equal, and whose angles are not right angles.

Rhomboid

A rhomboid is a parallelogam whose opposite sides are equal, and whose angles are not right angles.

A rhombus is a rhomboid having equal sides.

Rhombus

A rhombus is a rhomboid having equal sides.

An isosceles triangle is one having two of its sides equal.

Isosceles

An isosceles triangle is one having two of its sides equal.

An equilateral triangle is one having all of its sides equal.

Equilateral

An equilateral triangle is one having all of its sides equal.

A scalene triangle is one having no two of its sides equal.

Scalene

A scalene triangle is one having no two of its sides equal.

A roman moulding, called <em>Raised Fillet.</em> Its projection is generally made equal to its height. It may also be a depression, in which case it is called a <em>Sunk Fillet</em>.

Raised Fillet

A roman moulding, called Raised Fillet. Its projection is generally made equal to its height.…

A roman moulding, called a <em>Torus.</em> It is composed of a semicircle and a fillet. The smicircle projects from the fillet an amount equal to its radius. The concave addition above the fillet and the projection below the half round shows a combination of mouldings used in the base of a <em>Doric Column</em>.

Torus

A roman moulding, called a Torus. It is composed of a semicircle and a fillet. The smicircle…

A roman moulding, called a <em>Scotia.</em> It consists of two quarter circles one of which has a radius equal to twice the radius of the other. The centers of both arcs must be on the same horizontal line. It is generally applied in the bases of columns.

Scotia

A roman moulding, called a Scotia. It consists of two quarter circles one of which has a radius…

Having the form of a cross with equal arms, as the flowers of mustard.

Cruciate Flower

Having the form of a cross with equal arms, as the flowers of mustard.

A generic name for a desert-dweller, a term generally applied to Arab nomadic groups, who are found throughout most of the desert belt extending from the Atlantic coase of the Sahara.

Bedouin

A generic name for a desert-dweller, a term generally applied to Arab nomadic groups, who are found…

A regular body with six square faces; a rectangular parallelopiped, having all its edges equal.

Cube

A regular body with six square faces; a rectangular parallelopiped, having all its edges equal.

This illustration represents the field between two equal positive charges; in this case the lines of force do not pass from one to the other, but travel off to an infinate distance.

Electricity

This illustration represents the field between two equal positive charges; in this case the lines of…

This illustration shows the lines of force when a positive charge equal to 4 at A, and a negative charge of 1 at B, are used. A being numerically stronger than B, lines starting from A will not fall on B, but pass off to infinate distance.

Electricity

This illustration shows the lines of force when a positive charge equal to 4 at A, and a negative charge…

A is a positively charged conductor and B represents the equal and oppsite charge. When the conductor C is introduced into the field, some of the lines of force are divided, since they cannot exist in a conductor.

Electricity

A is a positively charged conductor and B represents the equal and oppsite charge. When the conductor…

"Spherical cell (resting stage of Amoeba) illustrating general or universal symmetry. Any plane passing through the center will divide it into two essentially equal portions." &mdash; Galloway

Spherical Cell

"Spherical cell (resting stage of Amoeba) illustrating general or universal symmetry. Any plane passing…

A money of account and a copper coin. Equal to three foourths of the United States cent at the time.

Half Pice

A money of account and a copper coin. Equal to three foourths of the United States cent at the time.

A money of account and a copper coin. Equal to three foourths of the United States cent at the time.

Half Pice

A money of account and a copper coin. Equal to three foourths of the United States cent at the time.

The smallest Anglo&ndash;Indian copper coin, equal to one third of a pice. About one fourth of a United States cent.

Pie

The smallest Anglo–Indian copper coin, equal to one third of a pice. About one fourth of a United…

The smallest Anglo&mdashIndian copper coin, equal to one third of a pice. About one fourth of a United States cent.

Pie

The smallest Anglo&mdashIndian copper coin, equal to one third of a pice. About one fourth of a United…

"In any right triangle, the square described on the hypotenuse is equal to the sum of the squares described on the other two sides. If A B C, is a right triangle, right angled at B, then the square described on the hypotenuse AC is equal to the sum of the suares described on the sides A B and B C." &mdash; Hallock, 1905

Right Triangle

"In any right triangle, the square described on the hypotenuse is equal to the sum of the squares described…

"A fixed pulley is one whose block is not movable. In this case, if the weight W be lifted by pulling down P, the other end of the cord W will evidently move the same distance upwards that P moves downwards; hence, P must equal W." &mdash; Hallock, 1905

Fixed Pulley

"A fixed pulley is one whose block is not movable. In this case, if the weight W be lifted by pulling…

"The principal part of the aneroid barometer is a cylindrical air-tight box of metal closed by a corrugated top of thin elastic metal. The air is exhausted from the box, which is then sealed. Evidently, the pressure of the air on the outside of the cover will cause the cover to curve inwards, as the space inside of the cover is void of pressure, until the resistance due to the elasticity of the cover, aided by the resistance of a spring beneath it, is equal to the force exerted by the air." &mdash; Hallock, 1905

Aneroid Barometer

"The principal part of the aneroid barometer is a cylindrical air-tight box of metal closed by a corrugated…

"Readily distinguished from the other groups of beetles by having the elytra much shorter then the abdomen, although they still suffice to cover the long membranous wings, which when not in use are completely folded beneah. The abdomen is long and exceedingly mobile, and is employed in folding and unfolding the wings. It is furnished at its extremity with two vesicles which can be protruded or withdrawn at pleasure, and from which, when irritated, many species emit a most disagreeable odor, although in a few the scent is more pleasing. They are voracious both in the larval and perfect states, feeding chiefly upon decaying animal and vegetable matters, although a few species devour living prey. Many of the smaller forms reside in and feed on mushrooms, some are found abundantly under putrescent plants, others in manure heaps, where they feed upon the maggots of flies, while there are a few forms which make their homes in the nests of the hornet and the ant." &mdash; Encyclopedia Britanica, 1893

Brachelytra

"Readily distinguished from the other groups of beetles by having the elytra much shorter then the abdomen,…

"These brick retorts are 9 feet long and with diameters of 22 and 13.5 inches, set four in an oven to one unarched furnace. Each retort will, it is affirmed, carbonize 500 tons cannel coal, or 2000 tons per oven of four, without any repairs whatever. Decayed bricks may be removed from these retorts and new ones inserted, and when thoroughly repaired they are again equal to new." &mdash; Encyclopedia Britannica, 1893

Brick Retort

"These brick retorts are 9 feet long and with diameters of 22 and 13.5 inches, set four in an oven to…

"The upper edge of the shelf on which the weights slide is graduated into equal divisions, and the weight is provided with a sharp tongue of metal in order that its posistion on the shelf may be accurately determined." &mdash;Encyclopedia Britannica, 1910

Slider of Kelvin Ampere Balance

"The upper edge of the shelf on which the weights slide is graduated into equal divisions, and the weight…

"The Duplex is made in two equal parts, each being capable of being worked alone. Each section consists of a semicircle of upright tubes forming the boiler proper, fitted with the diaphragm a, horizontal pipes forming the furnace f, a flow pipe b and a return pipe c, and an outlet d for removing sedimentary deposits from the interior." &mdash; Encyclopedia Britannica, 1893

Duplex Tubular Boiler

"The Duplex is made in two equal parts, each being capable of being worked alone. Each section consists…

A quadrilateral plane figure having four right angles and its opposite sides equal in length. The adjacent sides are unequal.

Rectangle

A quadrilateral plane figure having four right angles and its opposite sides equal in length. The adjacent…

"In the year 1589 the stocking-frame, the machine which mechanically produces the looped stitch in hosiery, was invented by the Rev. William Lee, a graduate of Cambridge, and native of Woodborough, near Nottingham. The fundamental principle of the apparatus consists in the substitution of a seperate hooked or barbed needle for the support and working of each loop, in place of the system whereby an indefinate number of loops are skewered on one or more wires or needles. At R is seen a thread of yarn passed over the needle stalks and within the terminal hooks. The yarn, it will be observed, is waved or depressed between each pair of needles, whereby sufficient yarn is secured to form the seperate loops of uniform size, and thus produce a regular equal fabric." &mdash; Encyclopedia Britannica, 1893

Hosiery

"In the year 1589 the stocking-frame, the machine which mechanically produces the looped stitch in hosiery,…

"Professor James Thomson's inward flow or vortex turbine has been selected as the type of reaction turbines. It is one of the best even in normal conditions of working, and the mode of regulation introduced is decidedly superior to that in most reaction turbines; it might almost be said to be the only mode of regulation which satisfies the conditions of efficient working, and it has been adopted in a modified form in the Leffel turbine, which is now largely used in america. The turbine has suction pipes, which permit the turbine to be placed at any height less than 30 feet above the tail-water level. The water enters the turbine by cast-iron supply pipes at A, and is discharged through two suction pipes S. The water on entering the case distributes itself through a rectangular supply chamber SC, from which it finds its way equally to the four guide-blade passages G. In these passages it acquires a velocity about equal to that due to half the fall, and is directed into the wheel at an angle of about 10 or 12 degrees with the tangent to its circumference. The wheel W receives the water in equal proportions from each guide-blade passage." &mdash; Encyclopedia Britannica, 1893

Reaction Turbine

"Professor James Thomson's inward flow or vortex turbine has been selected as the type of reaction turbines.…

"Professor James Thomson's inward flow or vortex turbine has been selected as the type of reaction turbines. It is one of the best even in normal conditions of working, and the mode of regulation introduced is decidedly superior to that in most reaction turbines; it might almost be said to be the only mode of regulation which satisfies the conditions of efficient working, and it has been adopted in a modified form in the Leffel turbine, which is now largely used in america. The turbine has suction pipes, which permit the turbine to be placed at any height less than 30 feet above the tail-water level. The water enters the turbine by cast-iron supply pipes at A, and is discharged through two suction pipes S. The water on entering the case distributes itself through a rectangular supply chamber SC, from which it finds its way equally to the four guide-blade passages G. In these passages it acquires a velocity about equal to that due to half the fall, and is directed into the wheel at an angle of about 10 or 12 degrees with the tangent to its circumference. The wheel W receives the water in equal proportions from each guide-blade passage." &mdash; Encyclopedia Britannica, 1893

Reaction Turbine

"Professor James Thomson's inward flow or vortex turbine has been selected as the type of reaction turbines.…

"Professor James Thomson's inward flow or vortex turbine has been selected as the type of reaction turbines. It is one of the best even in normal conditions of working, and the mode of regulation introduced is decidedly superior to that in most reaction turbines; it might almost be said to be the only mode of regulation which satisfies the conditions of efficient working, and it has been adopted in a modified form in the Leffel turbine, which is now largely used in america. The turbine has suction pipes, which permit the turbine to be placed at any height less than 30 feet above the tail-water level. The water enters the turbine by cast-iron supply pipes at A, and is discharged through two suction pipes S. The water on entering the case distributes itself through a rectangular supply chamber SC, from which it finds its way equally to the four guide-blade passages G. In these passages it acquires a velocity about equal to that due to half the fall, and is directed into the wheel at an angle of about 10 or 12 degrees with the tangent to its circumference. The wheel W receives the water in equal proportions from each guide-blade passage." &mdash; Encyclopedia Britannica, 1893

Reaction Turbine

"Professor James Thomson's inward flow or vortex turbine has been selected as the type of reaction turbines.…

"Professor James Thomson's inward flow or vortex turbine has been selected as the type of reaction turbines. It is one of the best even in normal conditions of working, and the mode of regulation introduced is decidedly superior to that in most reaction turbines; it might almost be said to be the only mode of regulation which satisfies the conditions of efficient working, and it has been adopted in a modified form in the Leffel turbine, which is now largely used in america. The turbine has suction pipes, which permit the turbine to be placed at any height less than 30 feet above the tail-water level. The water enters the turbine by cast-iron supply pipes at A, and is discharged through two suction pipes S. The water on entering the case distributes itself through a rectangular supply chamber SC, from which it finds its way equally to the four guide-blade passages G. In these passages it acquires a velocity about equal to that due to half the fall, and is directed into the wheel at an angle of about 10 or 12 degrees with the tangent to its circumference. The wheel W receives the water in equal proportions from each guide-blade passage." &mdash; Encyclopedia Britannica, 1893

Reaction Turbine

"Professor James Thomson's inward flow or vortex turbine has been selected as the type of reaction turbines.…

"Medusiform person, one of the Anthomedusae, detached from a hydroid colony of Syncoryne. Ocelli are seen at the base of the tentacles, and also (as an exception) groups of medusiform buds." &mdash; Encyclopedia Britannica, 1893

Anthomedusae

"Medusiform person, one of the Anthomedusae, detached from a hydroid colony of Syncoryne. Ocelli are…

"States that: A body when immersed in a fluid loses exactly as much of its weight as is equal to the weight of the dluid it displaces; or: A fluid sustains as mch of the weight of a body immersed in it as is equal to the weight of the fluid displaced by it." &mdash; Chambers' Encyclopedia, 1875

Archimedes Principle

"States that: A body when immersed in a fluid loses exactly as much of its weight as is equal to the…

"Popularly, banister or ballaster, the name given to small shafts or pillars set in a line at short equal distances, and supporting a cornice or coping. These miniature pillars have generally either a pear-shaped swelling at the lower end, or consist of two pear-shaped pieces, places above each other, a ring of moulding being set between them." &mdash; Chambers' Encyclopedia, 1875

Baluster

"Popularly, banister or ballaster, the name given to small shafts or pillars set in a line at short…

"Characteristic groups of Micrococci. Micrococcus prodigiosus." &mdash; The Encyclopedia Britannica, 1910

Micrococci

"Characteristic groups of Micrococci. Micrococcus prodigiosus." — The Encyclopedia Britannica,…

"Characteristic groups of Micrococci. Micrococcus vaccinae." &mdash; The Encyclopedia Britannica, 1910

Micrococci

"Characteristic groups of Micrococci. Micrococcus vaccinae." — The Encyclopedia Britannica, 1910

"Characteristic groups of Micrococci. Zoogloea stage of a Micrococcus, forming a close membrane on infusion." &mdash; The Encyclopedia Britannica, 1910

Micrococci

"Characteristic groups of Micrococci. Zoogloea stage of a Micrococcus, forming a close membrane on infusion."…

"A small coin of ancient Greece, in later times of silver, the sixth part of an Attic drachma, equal to 2.5 cents; multiples and sub-multiples of this coin were also used, and pieces of the value of 5, 4, 3, 2, 1.5 oboli, and 1/2, 1/3, 11/4th of an obolus respectively are to be found in collections." &mdash; Winston's Encyclopedia, 1919

Obolus

"A small coin of ancient Greece, in later times of silver, the sixth part of an Attic drachma, equal…

"The chain-pump consists of a tube or cylinder, the lower part of which is immersed in a well or reservoir, and the upper part enters the bottom of a cistern into which the water is to be raised. A chain is carried round a wheel at the top, and is furnished at equal distances with movable bottoms, which fit water-tight in the tube. As the wheel revolves, they successively enter the tube, and carry the water up before them, which is discharged into the cistern at the top of the tube." &mdash; Wells, 1857

Chain-Pump

"The chain-pump consists of a tube or cylinder, the lower part of which is immersed in a well or reservoir,…

"System of Wheels.&mdash;As the wheel and axle is only a modification of the simple lever, so a system of wheels acting on each other, and transmitting the power to the resistance, is only another form of the compound lever. The first wheel a, by means of the teeth, or cogs, around its axle, moved the second wheel, b, with a force equal to that of a lever, the long arm of which extends from the center to the circumference of the wheel, where the power p is suspended, and the short arm from the same center to the ends of the cogs. The dotted line c, passing through the center of the wheel a, shows the position of the lever, as the wheel now stands." &mdash;Comstock, 1850

System of Wheels

"System of Wheels.—As the wheel and axle is only a modification of the simple lever, so a system…

"Suppose the cistern a to be capable of holding one hundred gallons, and into its bottom there be fitted the tube b, bent, as seen in the figure, and capable of containing one gallon. The top of the cistern, and that of the tube, being open, pour water into the tube at c, and it will rise up through the perpendicular bend into the cistern, and if the process be continued, the cistern will be filled by pouring water into the tube. Now it is plain, that the gallon of water in the tube presses against the hundred gallons in the cistern, with a force equal to the pressure of the hundred gallons, otherwise, that in the tube would be forced upwards higher than that in the cistern, whereas, we find that the surfaces of both stand exactly at the same height." &mdash;Comstock, 1850

Water Pressure

"Suppose the cistern a to be capable of holding one hundred gallons, and into its bottom there be fitted…

"Suppose a number of vessels, of different shapes and sizes to have a communication between them, by means of a small tube, passing from the one to the other. If, now, one of these vessels be filled with water, or if water be poured into the tube A, all the other vessels will be filled at the same instant, up to the line B C. Therefore, the pressure of the water A, balances that in 1, 2, 3, while the pressure in each of these vessels is equal to that in the other, and so an equilibrium is produced throughout the whole series." &mdash;Comstock, 1850

Water Pressure

"Suppose a number of vessels, of different shapes and sizes to have a communication between them, by…

"An instrument called the hydrostatic bellows, also shows, in a striking manner, the great force of a small quantity of water, pressing in a perpendicular direction. This instrument consists of two boards, connected together with strong leather, in the manner of the common bellows. It is then furnished with a tube a, which communicated between the two boards. A person standing on the upper board may raise himself up by pouring water into the tube. If the tube holds an ounce of water, and has an area equal to a thousandth part of the area of the top of the bellows, one ounce of water in the tube will balance a thousand ounces placed on the bellows." &mdash;Comstock, 1850

Hydraulic Bellows

"An instrument called the hydrostatic bellows, also shows, in a striking manner, the great force of…

"Rupture of a Mountain.&mdash;There is no doubt, but in the operations of nature, great effects are sometimes produced among mountains, by a small quantity of water finding its way to a reservoir in the crevices of the rocks far beneath. Suppose, in the interior of a mountain, there should be a space of ten yards square, and an inch deep, filled with water, and closed up on all sides; and suppose that, in the course of time, a small fissure, no more than an inch in diameter, should be openeing by the water, from the height of two hundred feet above, down to this little reservoir. The consequence might be, that the side of the mountain would burst asunder, for the pressure, under the circumstances supposed, would be equal to the weight of five thousand tons." &mdash;Comstock, 1850

Mountain Rupture

"Rupture of a Mountain.—There is no doubt, but in the operations of nature, great effects are…

"Take a piece of ivory, or any other substance that will sink in water, and weigh it accurately in the usual manner; then suspend it by a thread, or hair, in the empty cup a, and balance it. Now pour water into the cup, and it will be found that the suspended body will lose a part of its weight, so that a certain number of grains must be taken from the opposite scale, in order to make the scales balance as before the water was poured in. The number of grains taken from the opposite scale, show the weight of a quantity of water equal to the bulk of the body so suspended." &mdash;Comstock, 1850

Water Weighing

"Take a piece of ivory, or any other substance that will sink in water, and weigh it accurately in the…

"If the strong tube, or barrel, be smooth, and equal on the inside, and there be fitted to it the solid piston, or plug a, so as to work up and down, air tight, by the handle b, the air in the barrel may be compressed into a space a hundred times less than its usual bulk. Indeed, if the vessel be of sufficient strength, and the force employed sufficiently great, its bulk may be lessened a thousand times, or in any proportion, according to the force employed; and if kept in this state for years, it will regain its former bulk the instant the pressure is removed." &mdash;Comstock, 1850

Compression Experiment

"If the strong tube, or barrel, be smooth, and equal on the inside, and there be fitted to it the solid…

"The pressure of the atmosphere may be easily shown by the tube and piston. suppose there is an orifice to be opened or closed by the valve b, as the piston a is moved up or down in its barrel. The valve being fastened by a hinge on the upper side, on pushing the piston down, it will open by the pressure of the air against it, and the air will make its escape. But when the piston is at the bottom of the barrel, on attempting to raise it again, towards the top, the valve is closed by the force of the external air acting upon it. If, therefore, the piston be drawn up in this state, it must be against the pressure of the atmosphere, the whole weight of which, to an extent equal to the diameter of the piston, must be lifted, while there will remain a vacuum or void space below it in the tube. if the piston be only three inches in diameter, it will require the full strength of a man to draw it to the top of the barrel, and when raised, if suddenly let go, it will be forced back again by the weight of the air, and will stright the bottom with great violence." &mdash;Comstock, 1850

Atmospheric Pressure

"The pressure of the atmosphere may be easily shown by the tube and piston. suppose there is an orifice…

"The twelve signs of the zodiac, together with the Sun, and the Earth revolving around him. When the Earth is at A, the Sun will appear to be just entering the sign Aries, because then, when seen from the Earth, he ranges towards certain stars at the beginning of that constellation. When the Earth is at C, the Sun will appear in the opposite part of the heavens, and therefore in the beginning of Libra. The middle line, dividing the circle of the zodiac into equal parts, is the line of the ecliptic." &mdash;Comstock, 1850

Zodiac Signs

"The twelve signs of the zodiac, together with the Sun, and the Earth revolving around him. When the…

"Elliptical Orbits.&mdash;It has been supposed that the Sun's attraction, which constitutes the Earth's gravity, was at all times equal, or that the Earth was at an equal distance from the Sun, in all parts of its orbit." &mdash;Comstock, 1850

Planet Motion

"Elliptical Orbits.—It has been supposed that the Sun's attraction, which constitutes the Earth's…

"The elliptical circle being supposed to be the Earth's orbit, with the Sun, S, in one of the foci. Now the spaces, 1, 2, 3, etc., though of different shapes, are of the same dimensions, or contain the same quantity of surface. The Earth, we have already seen, in its journey round the Sun, describes an ellipse, and moves more rapidly in one part of its orbit than in another. But whatever may be its actual velocity, its comparative motion is through equal areas in equal times. Thus its center passes from E to C, and from C to A, in the same period of time, and so of all the other divisions marked in the figure." &mdash;Comstock, 1850

Elliptical Orbit

"The elliptical circle being supposed to be the Earth's orbit, with the Sun, S, in one of the foci.…

"The Earth, whose diameter is 7,912 miles, is represented by the globe, or sphere. The straight line passing through its center, and about which it turns, is called its axis, and the two extremities of the axis are the poles of the Earth, A being the north pole, and B the south pole. The line C D, crossing the axis, passes quite round the Earth, and divides it into two equal parts. This is called the equinoctial line, or the equator. That part of the Earth situated north of this line, is caled the northern hemisphere, and that part south of it, the southern hemisphere. The small circles E F and G H, surrounding or including the poles, are called the polar circles." &mdash;Comstock, 1850

Earth Divisions

"The Earth, whose diameter is 7,912 miles, is represented by the globe, or sphere. The straight line…

"The machine is in fact a lathe with a few special features, such as the hollow mandrel, which enables it to operate upon a bar of any length. Dies mounted on a modified form of slide-rest cut the thread to the full depth at a single traverse, and a simple arrangement enables nuts to be tapped with equal facility. In some other varieties of screwing machines, more particularly those intended for hand power only, the outward resemblance to the turning lathe is less apparent, but if their action is looked into it will be found that in them as in almost all machine tools it is the principle of the slide which is mainly conducive to their success." &mdash;The Encyclopedia Britannica, 1903

Screwing Machine

"The machine is in fact a lathe with a few special features, such as the hollow mandrel, which enables…