ClipArt ETC
An illustration of Mance's method used to measure battery resistance.

Battery Resistance

An illustration of Mance's method used to measure battery resistance.

An illustration of Mance's method used to measure battery resistance.

Battery Resistance

An illustration of Mance's method used to measure battery resistance.

An illustration of the assisting and opposing method used to measure battery resistance.

Battery Resistance

An illustration of the assisting and opposing method used to measure battery resistance.

Uniting the theories of partial polygons of resistance and centres and lines of resistance, this buttress of blocks illustrates the tangential curve that is the line of pressures.

Buttress of Blocks

Uniting the theories of partial polygons of resistance and centres and lines of resistance, this buttress…

"A shunt-wound dynamo with an adjustable resistance, R." -Avery 1895

Shunt-wound Dynamo

"A shunt-wound dynamo with an adjustable resistance, R." -Avery 1895

"When a feather and a cent are dropped from the same height, the cent reaches jthe ground first. this is not because the cent is heavier, bu because the feather meets with more resistance from the air in proportion to its mass. If this resistance can be removed or equalized, the two bodies will fall equal distances in equal times, or with the same velocity. The resistance may be avoided by dropping them in a glass tube from which the air has been removed. The resistances may be nearly equalized by making the two falling bodies of the same size and shape bu of different weights, as in the preceding experiment." -Avery 1895

Velocities of Falling Bodies

"When a feather and a cent are dropped from the same height, the cent reaches jthe ground first. this…

"Remove the air from a high glass tube by means of an instrument called the air-pump... Then... drop a feather and a cent simultaneously, and they will reach the bottom at precisely the same instant. Let in the air and drop them, and the feather will be several seconds longer than the cent in reaching the bottom." —Quackenbos 1859

Two Objects Falling in a Vacuum

"Remove the air from a high glass tube by means of an instrument called the air-pump... Then... drop…

"Incandescence lamps operate essentially on the principle...[that] the current being sent through some substance that, because of its high resistance, becomes intensely heated and brilliantly incandescent. The only suitable substance known for such a resistance filament is carbon, which, carefully prepared and bent into a loop, is enclosed in a glass bulb from which the air is exhausted to prevent oxidation, i.e., combustion." -Avery 1895

Incandescence Lamp

"Incandescence lamps operate essentially on the principle...[that] the current being sent through some…

"Illustrating method of measuring insulation resistance." —Croft 1920

Measuring Insulation Resistance

"Illustrating method of measuring insulation resistance." —Croft 1920

"Testing the insulation resistance of an armature." —Croft 1920

Measure Armature Insulation Resistance

"Testing the insulation resistance of an armature." —Croft 1920

"Testing the insulation resistance of a motor or generator from its winding to ground." —Croft 1920

Measure Insulation Resistance of Motor

"Testing the insulation resistance of a motor or generator from its winding to ground." —Croft…

"In straight levers of the first kind, the fulcrum is between the power and the resistance, as in fig 1, where F is the fulcrum of the lever AB; P is the power, and W the weight or resistance."—Pettigrew, 1874

First Kind of Lever

"In straight levers of the first kind, the fulcrum is between the power and the resistance, as in fig…

"In the second order of levers, the resistance is between the fulcrum and the power; and, as before, P : W :: BF : AF, but the pressure of the fulcrum is equal to W-P, or the weight less the power."—Pettigrew, 1874

Second Kind of Lever

"In the second order of levers, the resistance is between the fulcrum and the power; and, as before,…

"In the third order of lever the power acts between the prop and the resistance, where also P : W :: BF : AF, and the pressure on the fulcrum is P-W, or the power less the weight."——Pettigrew, 1874

Third Kind of Lever

"In the third order of lever the power acts between the prop and the resistance, where also P : W ::…

"[This illustration] shows the path of a stone thrown obliquely from the hand. The propelling force sends it in a straight line to A, and would take it on in the same direction to B, were it not that, as soon as its velocity becomes sufficiently diminished, gravity and the air's resistance give it a circular motion to C, and finally bring it to the earth at D." —Quackenbos 1859

Projectile Motion of a Stone

"[This illustration] shows the path of a stone thrown obliquely from the hand. The propelling force…

The electrical symbol for resistance.

Resistance

The electrical symbol for resistance.

"When the brass plugs are inserted...the coils are short-circuited, i.e., practically, the whole of a current passing from block to block goes through the plug, but when a plug is withdrawn the current passes through the corresponding coil...By withdrawing the proper plugs, one may throw into the circuit and resistance desired, from a single ohm up to the full capacity of the box." -Avery 1895

Resistance Box

"When the brass plugs are inserted...the coils are short-circuited, i.e., practically, the whole of…

Any mechanical force that tends to retard or oppose motion

Element Resistance

Any mechanical force that tends to retard or oppose motion

The four fundamental forms of resistance: A, to tension; B, to compression parallel to fiber; C, to compression at right angle to fiber; D, to transverse tension; F, fiber of wood. Arrows indicate direction of force.

The Forms of Resistance

The four fundamental forms of resistance: A, to tension; B, to compression parallel to fiber; C, to…

"Nichols Rheostat. a, wooden frame; b, tinned iron strip; c, stationary, and c', movable binding-posts; d, copper strip for short-circuiting." -Whitney, 1911

Rheostat

"Nichols Rheostat. a, wooden frame; b, tinned iron strip; c, stationary, and c', movable binding-posts;…

"With a long main-line and many instruments in circuit, the resistance may be so great as to render the main-battery current so feeble that it cannot operate the sounder with sufficient energy to render the signals distinctly audible. This difficulty is met by introducing a 'local battery,' and a 'relay' at each station on the line." -Avery 1895

Telegraph Relay

"With a long main-line and many instruments in circuit, the resistance may be so great as to render…

"The Wheatstone bridge is used as a way to measure resistance of a unknown resitors." -Avery 1895

Wheatstone Bridge

"The Wheatstone bridge is used as a way to measure resistance of a unknown resitors." -Avery 1895

"The Wheatstone bridge is used as a way to measure resistance of a unknown resitors." -Avery 1895

Wheatstone Bridge in Circuit

"The Wheatstone bridge is used as a way to measure resistance of a unknown resitors." -Avery 1895

"The Wheatstone bridge is used as a way to measure resistance of a unknown resitors." -Avery 1895

Wheatstone Bridge with Resistors

"The Wheatstone bridge is used as a way to measure resistance of a unknown resitors." -Avery 1895

"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…