"In <em>optics</em>, a deviation in the rays of light when unequally refracted by a lens or reflected by a mirror, so that they do not converge and meet in a point or focus, but separate, forming an indistinct image of the object, or an indistinct image with prismatically colored edges."-Wright, 1902

Aberration

"In optics, a deviation in the rays of light when unequally refracted by a lens or reflected…

"The letter C marks the point where the vessel to be exhausted is attached." -Century, 1889

Mercury Air-Pump

"The letter C marks the point where the vessel to be exhausted is attached." -Century, 1889

The Atwood machine (or Atwood's machine) was invented in 1784 by Rev. George Atwood as a laboratory experiment to verify the mechanical laws of uniformly accelerated motion. Atwood's machine is a common classroom demonstration used to illustrate principles of physics, specifically mechanics.

The Atwood Machine

The Atwood machine (or Atwood's machine) was invented in 1784 by Rev. George Atwood as a laboratory…

"This is a very convenient and quite accurate method of determining specific gravity." &mdash; Ford, 1912

Beam balance

"This is a very convenient and quite accurate method of determining specific gravity." — Ford,…

"The most accurate method of determining the specific gravity of a mineral is by the use of a chemical balance. To one beam of the balance is suspended a wire basket which is so arranged that it can be immersed in a beaker of water. The basket is hung in the water and then counterbalanced by weights on the opposite pan of the balance. The mineral specimen to be tested, having been first weighed on the balance in the ordinary fashion, is now placed in the basket under the water and weighed again." &mdash; Ford, 1912

Chemical balance

"The most accurate method of determining the specific gravity of a mineral is by the use of a chemical…

"This is an instrument shaped something like a small clock, and the barometric pressure is read by means of a hand or indicator, on a scale of inches placed on the face like the minute divisions of a clock." &mdash; Waldo, 1896

Aneroid Barometer

"This is an instrument shaped something like a small clock, and the barometric pressure is read by means…

Binocular telescopes, or binoculars (also known as field glasses), are two identical or mirror-symmetrical telescopes mounted side-by-side and aligned to point accurately in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects.

Binocular Telescope

Binocular telescopes, or binoculars (also known as field glasses), are two identical or mirror-symmetrical…

Boulanger succeeded in producing a binocular of an entirely new type in 1859.

Binoculars

Boulanger succeeded in producing a binocular of an entirely new type in 1859.

The model of binoculars invented by E. Abbe.

Binoculars

The model of binoculars invented by E. Abbe.

"An air thermometer consists essentially of a large glass bulb at the upper end of a tube of small but uniform bore, the lower end of which dips into colored water." &mdash; Avery, 1895

Glass bulb

"An air thermometer consists essentially of a large glass bulb at the upper end of a tube of small but…

"A kind of compass for measuring the diameter of round bodies." &mdash; Williams, 1889

Calipers

"A kind of compass for measuring the diameter of round bodies." — Williams, 1889

"Simple Daniell cell for closed circuit work." &mdash; Hawkins, 1917

Daniell cell

"Simple Daniell cell for closed circuit work." — Hawkins, 1917

A magnetic compass.

Compass

A magnetic compass.

A cup of water next to a jar, with a tube running between the two.

Cup and jar

A cup of water next to a jar, with a tube running between the two.

A graduated cylinder.

Graduated cylinder

A graduated cylinder.

"The simplest way of measuring a force is to use a dynamometer, of which the spring-balance is a familiar example. The dynamometer may be graduated in pounds, grams, poundals, or dynes." &mdash; Avery, 1895

Dynamometer

"The simplest way of measuring a force is to use a dynamometer, of which the spring-balance is a familiar…

"Equipotential Lines about two similarly electrified spheres, A and B, the quantities of electricity being as 2:1. The lines of force are also shown radiating from the spheres." -Whitney, 1911

Equipotential

"Equipotential Lines about two similarly electrified spheres, A and B, the quantities of electricity…

A flask being heated over an open flame, with a tube and jar attached.

Heated flask

A flask being heated over an open flame, with a tube and jar attached.

(1564-1642) Italian physicist, mathematician, astronomer, and philosopher who was one of the great creators of experimental science.

Galileo Galilei

(1564-1642) Italian physicist, mathematician, astronomer, and philosopher who was one of the great creators…

"Secure the two ends of the wire by double-pointed tacks. Place a small pocket compass upon the block thus wound, and turn the block until the coils of wire are parallel to the needle when the circuit is open. Then pass a current through the coil. The deflection of the needle is much stronger than before, although, owing to the weakening of the cell, the deflection falls off after a time." &mdash; Avery, 1895

Galvanoscope

"Secure the two ends of the wire by double-pointed tacks. Place a small pocket compass upon the block…

"A zodiacal constellation, giving its name to a sign of the zodiac, lying east of Taurus, on the other side of the Milky Way." -Whitney, 1911

Gemini

"A zodiacal constellation, giving its name to a sign of the zodiac, lying east of Taurus, on the other…

A hand holding up a tube from a larger, mercury-filled tube.

Hand and barometer

A hand holding up a tube from a larger, mercury-filled tube.

A hand holding a tube, with one end in a bowl.

Hand with tube

A hand holding a tube, with one end in a bowl.

A pair of hands holding a glass tube filled with a dark liquid.

Hands with tube

A pair of hands holding a glass tube filled with a dark liquid.

"As generally made, a hydrometer of constant weight consists of a glass tube near the bottom of which are two bulbs. The lower and smaller bulb is loaded with mercury or shot. The tube and upper bulb contain air. The point to which it sinks when placed in water is marked zero. The tube is graduated, the scale being arbitrary, and varying with the purpose for which the instrument is intended." &mdash; Avery, 1895

Hydrometer of constant weight

"As generally made, a hydrometer of constant weight consists of a glass tube near the bottom of which…

"Hair hygrometer." &mdash; Waldo, 1896

Hair hygrometer

"Hair hygrometer." — Waldo, 1896

A laboratory as found in Pompeii.

Laboratory, Ancient

A laboratory as found in Pompeii.

"The Atwood machine consists of a wheel or pulley, R, over the grooved edge of which are balanced two equal weights suspended by a long silk thread which is both light and strong. The axle of this wheel is preferably supported upon the circumfrences of four friction wheels, r, r, r', r', for greater delicacy of motion. As the thread is so light that its weight may be disregarded, it is evident that the weights will be in equilibrium whatever their position." &mdash; Avery, 1895

Atwood Machine

"The Atwood machine consists of a wheel or pulley, R, over the grooved edge of which are balanced two…

"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." &mdash; Hawkins, 1917

Wimshurst Electric Machine

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

A bar or mass of steel or iron to which the peculiar properties of the loadstone have been imparted, either by contact or by other means.

Magnet

A bar or mass of steel or iron to which the peculiar properties of the loadstone have been imparted,…

An illustration of a horseshoe shaped magnet.

Horseshoe Magnet

An illustration of a horseshoe shaped magnet.

An illustration of a rectangle shaped steel magnet with "consequent poles at a and b." -Century, 1889

Rectangle Shaped Steel Magnet

An illustration of a rectangle shaped steel magnet with "consequent poles at a and b." -Century, 1889

(1874-1937) Italian inventor and Nobel Prize winner for his invention of wireless telegraphy.

Guglielmo Marconi

(1874-1937) Italian inventor and Nobel Prize winner for his invention of wireless telegraphy.

An illustration of the concave of a meniscus.

Concave of Meniscus

An illustration of the concave of a meniscus.

An illustration of the convex of a meniscus.

Convex of Meniscus

An illustration of the convex of a meniscus.

"A microscope consists of a lens or a combination of lenses used to observe small objects, often so minute as to be invisible to the unaided eye." &mdash; Avery, 1895

Microscope

"A microscope consists of a lens or a combination of lenses used to observe small objects, often so…

An illustration of a binocular microscope.

Binocular Microscope

An illustration of a binocular microscope.

A needle, used for dissection.

Needle

A needle, used for dissection.

"This picture is based upon a photograph of a painting which has won great fame during recent years. The artist has represented Pasteur, the celebrated scientist, busily at work in his laboratory, recording the results of his microscopal study of bacteria. As the great master of modern science rests for a moment from his midnight researches, he appears to see in a vision the victims of pestilence, famine, and infectious diseases imploring relief from the good angel who symbolizes the wonderful victories won by Pasteur in combating disease." — Blaisedell, 1904

Louis Pasteur

"This picture is based upon a photograph of a painting which has won great fame during recent years.…

"A pendulum has a strong tendency to maintain its plane of oscillation, a fact that has been used in the experimental demonstration of the earth upon its axis. The chief function of the wheel-work of a clock is to register the number of vibrations of the pendulum. If the clock gains time, the pendulum is lengthened by lowering the bob, if it loses time, the pendulum is shortened by raising the bob." &mdash; Avery, 1895

Pendulum

"A pendulum has a strong tendency to maintain its plane of oscillation, a fact that has been used in…

A device used for demonstrating the elastic properties of materials.

Physics demonstration

A device used for demonstrating the elastic properties of materials.

A pipette, half filled with liquid.

Pipette

A pipette, half filled with liquid.

Scientist and postmaster general.

Sir Lyon Playfair

Scientist and postmaster general.

A pair of similar magnetic poles repelling, the magnetic forces shown by iron filings.

Repelling poles

A pair of similar magnetic poles repelling, the magnetic forces shown by iron filings.

This furnace is used to purify a gold concentrate. The gold concentrates, if non-pyritic, are treated in grinding pans in the bottom of which mercury is placed. The amalgam (mercury alloy), after squeezing out the excess mercury, is heated in the retort, to distil (separate) off the rest and leave the gold, which is then melted and cast into bars of gold bullion of varying fineness.

Retort Furnace for Gold Bullion

This furnace is used to purify a gold concentrate. The gold concentrates, if non-pyritic, are treated…

&quot;A vertical rod, generally of iron, with a heavy metallic foot, and a number of metallic rings, of different sizes ... the whole serves to support a retort or other vessel, properly adjusted as to height, over a lamp-flame.&quot; -Whitney, 1911

Retort Stand

"A vertical rod, generally of iron, with a heavy metallic foot, and a number of metallic rings,…

"Ruedorf's sand-bath, a simple form of sand-bath in which the temperature can be regulated by raising or lowering an S-shaped burner." -Whitney, 1911

Ruedorf's Sand Bath

"Ruedorf's sand-bath, a simple form of sand-bath in which the temperature can be regulated by raising…

"inverted Vertical Pendulum Seismograph. Marvin System. A stiff vertical tube, pivoted at its bottom end, carries a very heavy mass near its upper end, and is rendered stable or astatic by the elastic reaction of a central steel rod which has its bottom end firmly fixed inside the heavy mass and its top end attached to the framework on the pier. The horizontal motion of the ground and pier relative to the steady mass is magnified 120 times and inscribed on smoked-paper record-sheets by two sets of multiplying levers. One records the north-south, the other the east-west component of motion." -Whitney, 1911

Pendulum Seismograph

"inverted Vertical Pendulum Seismograph. Marvin System. A stiff vertical tube, pivoted at its bottom…

"Seismoscope. a, heavy mass supported by loop at point near center of gravity; b, point on which upper side of loop rests; c, long needle projecting from upper side of loop; d, conducting-wire; e, binding-post; f, long arm of lever pivoted at k; g, point where end of lever rests on end of needle; h, mercury-cup." -Whitney, 1911

Seismoscope

"Seismoscope. a, heavy mass supported by loop at point near center of gravity; b, point on which upper…

"A glass vessel used to separate liquids which differ in specific gravity and are not miscible." -Whitney, 1911

Separator

"A glass vessel used to separate liquids which differ in specific gravity and are not miscible." -Whitney,…

"A bent tube with one limb longer than the other, by means of which a liquid can be drawn off to a lower level over the side of a vessel or other point higher than the upper surface of the liquid."&mdash;Finley, 1917

Siphon

"A bent tube with one limb longer than the other, by means of which a liquid can be drawn off to a lower…

"C. Collimator; P, center of group of prisms; T, telescope; s, slit through which the ray of light enters, R, ray on its progress through prisms to telescope."&mdash;Finley, 1917

Spectroscope

"C. Collimator; P, center of group of prisms; T, telescope; s, slit through which the ray of light enters,…

"The famous English evolutionist, Herbert Spencer, was born in Derby in 1820." —The Popular Cyclopedia, 1888

Herbert Spencer

"The famous English evolutionist, Herbert Spencer, was born in Derby in 1820." —The Popular Cyclopedia,…

Three spring-balances hooked together around a small ring.

Spring-balances

Three spring-balances hooked together around a small ring.

A hand with bar demonstrating the attractive properties of static electricity.

Demonstration of Static Electricity

A hand with bar demonstrating the attractive properties of static electricity.

A hand with a rod, demonstrating the attractive properties of static electricity.

Demonstration of Static Electricity

A hand with a rod, demonstrating the attractive properties of static electricity.

A test tube

Test tube

A test tube

"Thermometer bulb and stem." &mdash; Waldo, 1896

Thermometer

"Thermometer bulb and stem." — Waldo, 1896

"Mercurial thermometer." &mdash; Waldo, 1896

Mercurial thermometer

"Mercurial thermometer." — Waldo, 1896

A pair of tourmaline tongs.

Tourmaline tongs

A pair of tourmaline tongs.