ClipArt ETC
"Consequent pole bipolar field magnet with two coils on the core." — Hawkins, 1917

Bipolar field magnet

"Consequent pole bipolar field magnet with two coils on the core." — Hawkins, 1917

"Method of winding magnet spool so that the two ends of the coil will come to the outside. This method has also been used for induction coils, where it is desirable to keep the ends of the wire away from the core and primary coil." — Hawkins, 1917

Magnetic spool

"Method of winding magnet spool so that the two ends of the coil will come to the outside. This method…

"In order to make the winding and connections clear, one coil and the commutator is shown assembled, although the latter is not put in place until after all the sections have been wound, the ends of the wires being temporarily twisted together until all can be soldered to the risers." — Hawkins, 1917

Siemens' drum winding

"In order to make the winding and connections clear, one coil and the commutator is shown assembled,…

"Side view of built up armature core. The sheet metal ring sections containing the teeth are fastened into dovetail notches in the spider as shown." — Hawkins, 1917

Armature core

"Side view of built up armature core. The sheet metal ring sections containing the teeth are fastened…

Gramme's small electric light machine, with jamin magnets.

Gramme's Light Machine

Gramme's small electric light machine, with jamin magnets.

An instrument to send messages by means of electricity, either at short or long distances. An instrument of this kind is frequently called the electric telegraph.

Telegraph

An instrument to send messages by means of electricity, either at short or long distances. An instrument…

An instrument for reproducing sound at a distance by the transmission of impulses through the agency of electricity over a conducting wire or cord.

Telephone

An instrument for reproducing sound at a distance by the transmission of impulses through the agency…

A ray capable of shooting off 200 volts of electricity for self defense.

Spotted Torpedo

A ray capable of shooting off 200 volts of electricity for self defense.

This illustration shows pure hydrogen being collected by passing electricity through a dilute acid.

Hydrogen

This illustration shows pure hydrogen being collected by passing electricity through a dilute acid.

This illustration shows the field between two equally and oppositely charged spheres, mapped out by lines of force.

Electricity

This illustration shows the field between two equally and oppositely charged spheres, mapped out by…

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…

This illustration shows the field of force due to a charge 1 at A, and a like charge 4 at B.

Electricity

This illustration shows the field of force due to a charge 1 at A, and a like charge 4 at B.

This illustration shows the field of force between two parallel planes. At the edges its lines of foce curve out. Some pass from the back of one plane to the back of the other.

Electricity

This illustration shows the field of force between two parallel planes. At the edges its lines of foce…

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…

a is called the cathode, b is a plate of metal mounted inside the tube and in the path of the rays; d is the portion of the glass protected from the cathode rays by the screen.

Shadow Tube

a is called the cathode, b is a plate of metal mounted inside the tube and in the path of the rays;…

This illustration shows rays attracted to a magnet, and exerting force upon the object against which they are striking.

Cathode

This illustration shows rays attracted to a magnet, and exerting force upon the object against which…

"ABCD is a cylinder of glass 1 foot in diameter and 1 foot high. This cylinder is closed by a glass lid pierced centrically by two openings, each about 20 lines wide. Into the middle opening is cemented a glass tube 2 feet high, to the upper end of which is fitted a torsion head; the separate parts of the head are shown larger at the side of the figure. H is a collar cemented to the glass tube; MO a metal disc, divided on the edge into 360 degrees; this disc is fastened to a tube N, which slips into the collar H. K is a button whose neck turns easily in a hole in MO; to the lower part of the button is fastened a small clamp, which seizes the wire of the balance. I is an arm with a small projecting piece which slips over the edge of the disc MO." — Encyclopedia Britannica, 1893

Torsion Balance

"ABCD is a cylinder of glass 1 foot in diameter and 1 foot high. This cylinder is closed by a glass…

"Faraday used in his experiments two identical pieces of apparatus, which were vertually two spherical Leyden jars. The outer coating EF was divided into two hemispheres, which could be fitted together airtight. The lower hemisphere F was fitted to a perforated stem, provided with a stop-cock G, so that it could be screwed to an airpump while the apparatus was being exhausted, and afterwards screwed into a foot H. The upper hemisphere was pierced by a tube, into which was cemented a shellac plug B. C is a metal wire passing down through B, which supports the hollow metal sphere D, forming the inside armature, and carries the metal ball A, by means of which D can be charged and discharged." — Encyclopedia Britannica, 1893

Faraday Experiment

"Faraday used in his experiments two identical pieces of apparatus, which were vertually two spherical…

"The best method for comparing resistances with great accuracy is the modification of Wheatstone's bridge introduced by Kirchhoff. KL is a platinum-iridium wire, DK and HL are stout copper terminals to which it is soldered, DAE, EGH, FBS are stout copper pieces with binding screws and terminals for mercury cups, by means of which resistances R, T, U, S can be inserted at D, E, F, H. A, B, and G are binding screws for the battery wires and one end of the galvanometer wire." — Encyclopedia Britannica, 1893

Wheatstones Bridge

"The best method for comparing resistances with great accuracy is the modification of Wheatstone's bridge…

"This instrument consists of a glass tube of narrow bore, 16 to 17 inches long, to which is blown a glass globe 3 to 4 inches in diameter. This tube is partially filled with some colored fluid which confines the air in the flobe, a wide reservoir at the other end of the tube allows the fluid to accumulate without sensible change of level. The stand of the instrument consists of two pieces hinged together, so that the tube can be laced at a small inclination to the horizon." — Encyclopedia Britannica, 1893

Reibungselectricitat

"This instrument consists of a glass tube of narrow bore, 16 to 17 inches long, to which is blown a…

"ABC is a horizontal coil of wire terminating at the binding screws a, b. FG is a ring-shaped trough of mercury for the sliding contacts. A wire connects the mercury with the binding screw d. DE is an upright support screwed into a metal base D in connection with the binding screw c, and terminating above in a mercury cup E. When required, DE can be replaced by the shorter supports D'E' and D"E". HLK is a support for a screw L, which carries an adjustible center." — Encyclopedia Britannica, 1893

Electric Apparatus

"ABC is a horizontal coil of wire terminating at the binding screws a, b. FG is a ring-shaped trough…

"This apparatus shows the rotation at once of a magnet and of a movable conductor. The rotating pieces are the magnet sn, which is tied to the copper peg at the bottom of G by means of a piece of string, and swims round the vertical current buoyed up by the mercury in G, and the wire DE, which is hinged to D by a thin flexible wire, and swims round the pole of the vertical magnet n's'." — Encyclopedia Britannica, 1893

Faraday Apparatus

"This apparatus shows the rotation at once of a magnet and of a movable conductor. The rotating pieces…

"A current is caused to pass from the mercury through C along the radius of the disc A through the field of magnetic force due to the horse-shoe magnet NO. The result is that the wheel rotates in the direction indicated by the arrow." — Encyclopedia Britannica, 1893

Barlow Apparatus

"A current is caused to pass from the mercury through C along the radius of the disc A through the field…

"D is a Leyden jar, fastened to a stand in such a way that its outer armature can be insulated or connected to earth at will. The inner armature is in good metallic connection with the knob C. A horizontal metal piece A is mounted on a glass pillar, and carries another knob, which can be set at any required distance from C by means of a screw and graduation. The piece A is connected with the outer armature of the jar by a thin wire B contained in a glass tube." — Encyclopedia Britannica, 1893

Lanes Jar

"D is a Leyden jar, fastened to a stand in such a way that its outer armature can be insulated or connected…

"Discharging Electroscope" — Encyclopedia Britannica, 1893

Electroscope

"Discharging Electroscope" — Encyclopedia Britannica, 1893

"Cavallo's electroscope embodies the double pendulum principle. It consists of two fine silver wires loaded with small pieces of cork or pith, and suspended inside a small glass cylinder. Through the cap which closes the cylinder passes the stout wire from which the pendulums are suspended. This wire ends in a thimble-shaped dome A, which comes down very nearly to the cap; the outside of the cap is part of the wire and covered with sealing wax, and the object of the dome is to keep moisture from the stem, so that the electroscope could be used in the open air even in rainy weather." — Encyclopedia Britannica, 1893

Cavallos Electroscope

"Cavallo's electroscope embodies the double pendulum principle. It consists of two fine silver wires…

"The gold leaves are gummed on the two sides of a flat piece of metal carried by a stout stem, which passes through the top of a glass shade and ends in a flat disc. By means of this disc we may convert the instrument into Volta's condensing electroscope." — Encyclopedia Britannica, 1893

Bennets Electroscope

"The gold leaves are gummed on the two sides of a flat piece of metal carried by a stout stem, which…

"The electrometer of Henley, sometimes called Henley's quadrant Henley electrometer, may be taken as the type of single pendulum electroscopes. It consists essentially of a pendulum A hinged to meter a verticle support C, which carries a vertical graduated semicircle B, by means of which the deviation of A from the vertical can be indicating the state of electrification of the prime conductors of electric machines. The stem is screwed into the conductor, and the divergence of the pendulum indicated roughly the charge." — Encyclopedia Britannica, 1893

Henleys Electrometer

"The electrometer of Henley, sometimes called Henley's quadrant Henley electrometer, may be taken as…

"The sine electrometer of August, is a modification of the single pendulum electroscope, analogous in principle to Pouillet's sine compass. A is a pendulum suspended by two threads to secure motion in one plane; B is a ball fixd to the case, and connected with a suitable electrode." — Encyclopedia Britannica, 1893

Sine Electrometer

"The sine electrometer of August, is a modification of the single pendulum electroscope, analogous in…

"D is a needle, formed of light silver wire, suspended by a fine glass fiber, from a torsion head A. Below the needle is a piece of sheet metal NE, divided half through by a notch in the middle, and then bent in opposite directions on both sides of the notch, so that, when looked at end on, it appears like a Y." — Encyclopedia Britannica, 1893

Dellman's Electrometer

"D is a needle, formed of light silver wire, suspended by a fine glass fiber, from a torsion head A.…

"C is an insulated disc, over which is suspended another disc, hung from the arm of a balance, and connected with the earth. A weight w is put in a scale attached to the other arm of the balance. The insulated disc is connected with the internal armature B of a Leyden jar, whose outer armature is in connection with the suspended disc, Electricity is conveyed to B, and the quantity q measured by a small Lane's jar A, until the electric attraction at C is just sfficient to turn the balance." — Encyclopedia Britannica, 1893

Disc Electrometer

"C is an insulated disc, over which is suspended another disc, hung from the arm of a balance, and connected…

"Section of Thomson's Portable Electrometer." — Encyclopedia Britannica, 1893

Portable Electrometer

"Section of Thomson's Portable Electrometer." — Encyclopedia Britannica, 1893

"Thomson's absolute electrometer is an adaptation of the attracted disc principle for absolute determinations. We give merely an indication of its different parts, referring to Thomson a paper for details." — Encyclopedia Britannica, 1893

Absolute Electrometer

"Thomson's absolute electrometer is an adaptation of the attracted disc principle for absolute determinations.…

"Dry Pile Electroscope." — Encyclopedia Britannica, 1893

Dry Pile Electroscope

"Dry Pile Electroscope." — Encyclopedia Britannica, 1893

"Elevation and section of Thomson's Quadrant Electrometer." — Encyclopedia Britannica, 1893

Quadrant Electrometer

"Elevation and section of Thomson's Quadrant Electrometer." — Encyclopedia Britannica, 1893

"The coil is of flat, rectangular shape, with a narrow central opening just large enough to allow one of the magnets of the astatic system to swing freely. The other magnet swings over a graduated circle placed on the top of the coil, and serves also as an index. Sometimes a mirror and scale are substituted for the index and graduated circle. The sole on which the coil stands is movable on a fixed piece which can be levelled by means of three screws." &mdash Encyclopedia Britannica, 1893

Astatic Multiplier

"The coil is of flat, rectangular shape, with a narrow central opening just large enough to allow one…

"A very convenient form of Thomson's galvanometer, the only specimen of its kind we have seen. The peculiarity of its construction consists in the connection between the scale and the galvanometer, which saves much trouble in adjusting the instrument." — Encyclopedia Britannica, 1893

Thomsons Galvonometer

"A very convenient form of Thomson's galvanometer, the only specimen of its kind we have seen. The peculiarity…

Elliot's Astatic Galvonometer.

Elliots Astatic Galvonometer

Elliot's Astatic Galvonometer.

Galvanometer designed by Professor Maxwell.

Galvonometer

Galvanometer designed by Professor Maxwell.

"Hot-wire instruments working on the sag principle can be used in any position if properly contructed, and are very portable." —Encyclopedia Britannica, 1910

Hot-wire Ammeter

"Hot-wire instruments working on the sag principle can be used in any position if properly contructed,…

"A much better form of electromagnetic ammeter can be constructed on a principle now extensively employed, which consists in pivoting in the strong field of a permanent magnet a small coil through which a part of the current to be measured is sent." —Encyclopedia Britannica, 1910

Shunted Movable Coil Ammeter

"A much better form of electromagnetic ammeter can be constructed on a principle now extensively employed,…

"The connexions of all these six coils are such that when a current is passed through the whole of the coils in series, forces of attraction and repulsion are brought into existence which tend to force one movable coil upwards and the other movable coil downwards." —Encyclopedia Britannica, 1910

Connexions of Kelvin Ampere Balance

"The connexions of all these six coils are such that when a current is passed through the whole of the…

"When a current is passed through the instrument it causes one end of the movable system to tilt downwards, and the other end upwards; the sliding weight is then moved along the tray by means of a silk cord until equilibrium is again established." —Encyclopedia Britannica, 1910

Lord Kelvin's Ampere Balance

"When a current is passed through the instrument it causes one end of the movable system to tilt downwards,…

"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." —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…

An edgewise switchboard ammeter.

Edgewise Switchboard Ammeter

An edgewise switchboard ammeter.

"The electrical machine most usually employed consists of a large circular plate of glass, mounted upon a metallic axis, and supported upon pillars fixed to a secure base, so that the plate can, by means of a handle, w, be turned with ease. Upon the supports of the glass, and fixed so as to press easily but uniformly on the plate, are four rubbers, marked r r r r in the figure; and flaps of silk, s s, oiled on one side, are attached to these, and secured to fixed supports by several silk cords. When the machine is put in motion, these flaps of silk are drawn tightly against the glass, and thus the friction is increased, and electricity excited. The points p p collect the electricity from the glass, and convey it to the conductor, c, which is supported by the glass rod g." —Wells, 1857

Electrical Machine

"The electrical machine most usually employed consists of a large circular plate of glass, mounted upon…

A hydrometer used to measure the amount of salt in any given solution.

Salinometer

A hydrometer used to measure the amount of salt in any given solution.

An automobile used for transportation that is run completely off electricity.

Electric Automobile

An automobile used for transportation that is run completely off electricity.

An automobile used for transportation that is run completely off electricity.

Electric Automobile

An automobile used for transportation that is run completely off electricity.

A profile of Benjamin Franklin

Benjamin Franklin

A profile of Benjamin Franklin

When the atmosphere is highly charged with electricity, faint tinges of fire are often seen on the ends of bodies in connection with the earth, like the masts of ship, steeples, etc., due to an electric charge, known as the <em>brush-discharge</em>.

Elmo's Fire

When the atmosphere is highly charged with electricity, faint tinges of fire are often seen on the ends…

Auroras are caused by the passage of electricity through the rare air of the upper regions.

Aurora Borealis

Auroras are caused by the passage of electricity through the rare air of the upper regions.

(1847-1931) Famous American inventor.

Thomas Alva Edison

(1847-1931) Famous American inventor.

"A shunt, in electricity, is a conductor placed between two points in closed circuit, to divert or shunt part of the current."&mdash;Finley, 1917

Shunt

"A shunt, in electricity, is a conductor placed between two points in closed circuit, to divert or shunt…

"In all the arc lamps in common use, the coil, by means of which the automatic maintenance of the arc is kept up, is placed as a shunt across the its poles."&mdash;Finley, 1917

Arc lamp

"In all the arc lamps in common use, the coil, by means of which the automatic maintenance of the arc…

Portrait of Thomas Edison

Thomas A Edison

Portrait of Thomas Edison

"The water in resovoirs A and B stands at different heights. As long as this difference of level is maintained, water from B will flow through the pipe R to A. If by means of a pump P the level in B be kept constant, flow through R will also be maintained. Here, by means f the work expended on the pump, the level in the resovoir is kept constant; and in the corresponding case of the electric current...a constant difference of potential is maintanied." -Hawkins, 1917

Analogy of Water Flow to Electric Current

"The water in resovoirs A and B stands at different heights. As long as this difference of level is…

"...consists of a glass jar coated inside and outside with tinfoil, or some other thin sheet metal, except three or four inches at top, lef uncoated for insulation between the coated surfaces. This jar is closed with an insulating cover, through which a brass rod extends to the inside coating, and terminates above in a ball." -Atkinson 1903

Leyden Jar

"...consists of a glass jar coated inside and outside with tinfoil, or some other thin sheet metal,…

"Machines of this kind may be constructed with as many pairs of plaes, combs, and brushes as can be conveniently combined together; four-plate machines being common, in which the relative positions of each pair of plates are reversed, as shown..." -Atkinson 1903

Four-Plate Machine

"Machines of this kind may be constructed with as many pairs of plaes, combs, and brushes as can be…