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Plant with large root system. Bracts at the top with spore cases.

Lycopodium Carolinianum

Plant with large root system. Bracts at the top with spore cases.

Samuel Morse explaining his telegraph to members of Congress. Morse made his last trip to Washington, D.C., in December 1842, stringing "wires between two committee rooms in the Capitol, and sent messages back and forth" to demonstrate his telegraph system.

Samuel Morse

Samuel Morse explaining his telegraph to members of Congress. Morse made his last trip to Washington,…

The great low plain of North America lies between the Atlantic system on the east and the Pacific system of the west.

Plains

The great low plain of North America lies between the Atlantic system on the east and the Pacific system…

The digestive system of a katydid.

Digestive System

The digestive system of a katydid.

The digestive system of a grasshopper.

Digestive System

The digestive system of a grasshopper.

The Tracheal tube of an insect, showing the structure and methods of branching.

Tracheal

The Tracheal tube of an insect, showing the structure and methods of branching.

Plate-like covering of white grubs.

Spiracles

Plate-like covering of white grubs.

Shows how air enters the spiracles into the respiratory system of an insect.

Spiracles

Shows how air enters the spiracles into the respiratory system of an insect.

A toothed slit of a spiracle of the respiratory system of an insect.

Spiracles

A toothed slit of a spiracle of the respiratory system of an insect.

A spiracle of the respiratory system of an insect.

Spiracles

A spiracle of the respiratory system of an insect.

Conical spiracle set in a pit, protected by crossed hairs.

Spiracles

Conical spiracle set in a pit, protected by crossed hairs.

Crossed hair section of a spiracle in the respiratory system of an insect.

Spiracles

Crossed hair section of a spiracle in the respiratory system of an insect.

A lip-like spiracle of the respiratory system of an insect.

Spiracles

A lip-like spiracle of the respiratory system of an insect.

An unprotected round spiracle of an insect's respiratory system.

Spiracles

An unprotected round spiracle of an insect's respiratory system.

An unprotected slit-like spiracle of an insect's respiratory system.

Spiracles

An unprotected slit-like spiracle of an insect's respiratory system.

(1748-1832) An English jurist, philosopher, and legal and social reformer.

Jeremy Bentham

(1748-1832) An English jurist, philosopher, and legal and social reformer.

(1678-1751) Henry Bolingbroke was an English statesman and political writer.

Lord Bolingbroke

(1678-1751) Henry Bolingbroke was an English statesman and political writer.

(1729-1797) An Anglo-Irish statesman, author, orator, political theorist, and philosopher, who served for many years in the British House of Commons as a member of the Whig party.

Edmund Burke

(1729-1797) An Anglo-Irish statesman, author, orator, political theorist, and philosopher, who served…

(100 BC- 44 BC) A Roman military and political leader and one of the most influential men in world history.

Julius Caesar

(100 BC- 44 BC) A Roman military and political leader and one of the most influential men in world history.

Orthogonal projection of a closed plane-faced polyhedron.

Polyhedron

Orthogonal projection of a closed plane-faced polyhedron.

Orthogonal projection of a closed plane-faced polyhedron.

Polyhedron

Orthogonal projection of a closed plane-faced polyhedron.

Willis' shorthand alphabet, based on the orthographic principle.

Willis system of shorthand

Willis' shorthand alphabet, based on the orthographic principle.

Rich's shorthand alphabet, based on the orthographic principle.

Rich's system of shorthand

Rich's shorthand alphabet, based on the orthographic principle.

Gurney's shorthand alphabet, based on the orthographic principle.

Gurney's system of shorthand

Gurney's shorthand alphabet, based on the orthographic principle.

Byrom's shorthand alphabet, based on the orthographic principle.

Byrom's system of shorthand

Byrom's shorthand alphabet, based on the orthographic principle.

Taylor's shorthand alphabet, based on the orthographic principle.

Taylor's system of shorthand

Taylor's shorthand alphabet, based on the orthographic principle.

Calendar's shorthand alphabet, based on the orthographic principle.

Calendar's system of shorthand

Calendar's shorthand alphabet, based on the orthographic principle.

Lyle's shorthand alphabet, based on the phonetic principle.

Lyle's system of shorthand

Lyle's shorthand alphabet, based on the phonetic principle.

Towndrow's shorthand alphabet, based on the phonetic principle.

Towndrow's system of shorthand

Towndrow's shorthand alphabet, based on the phonetic principle.

Pitman's shorthand alphabet, based on the phonetic principle.

Pitman's system of shorthand

Pitman's shorthand alphabet, based on the phonetic principle.

Everett's shorthand alphabet, based on the phonetic principle.

Everett's system of shorthand

Everett's shorthand alphabet, based on the phonetic principle.

Pocknell's shorthand alphabet, based on the phonetic principle.

Pocknell's system of shorthand

Pocknell's shorthand alphabet, based on the phonetic principle.

Beale's shorthand alphabet, based on the phonetic principle.

Beale's system of shorthand

Beale's shorthand alphabet, based on the phonetic principle.

Janes' shorthand alphabet, based on the phonetic principle.

Janes' system of shorthand

Janes' shorthand alphabet, based on the phonetic principle.

Diagram of a neuron. Labels: A, axon arising from the cell-body and branching at its termination; D, dendrites; C and N, cell-body composed of C, cytoplasm, and N, nucleus.

Diagram of a Neuron

Diagram of a neuron. Labels: A, axon arising from the cell-body and branching at its termination; D,…

Diagram illustrating the general arrangement of the cerebrospinal nervous system.

Diagram of the Human Nervous System

Diagram illustrating the general arrangement of the cerebrospinal nervous system.

Nerve fibers. Labels: a, nerve-fiber, showing complete interruption of the white substance; b, another nerve fiber with nucleus. In both these nerve fibers the white substance is stained black with osmic acid, and the axon is seen running as an uninterrupted strand through the center of the fiber. c, ordinary nerve fiber unstained; d, e, smaller nerve fiber; f, varicose nerve fiber; g, non-medullated nerve fibers.

Nerve Fibers

Nerve fibers. Labels: a, nerve-fiber, showing complete interruption of the white substance; b, another…

General view of the sympathetic nervous. Labels: 1,2,3, cervical ganglia; 4, 1st thoracic ganglion; 5, 1st lumbar ganglion; 6, 7, sacral ganglion; 9, 9, cardiac nerves; 13, branch of pneumogastric nerve ending in semi-lunar ganglion; 14, epigastric plexus.

General View of the Sympathetic Nervous System

General view of the sympathetic nervous. Labels: 1,2,3, cervical ganglia; 4, 1st thoracic ganglion;…

Diagram showing the relation of the cerebrospinal to the sympathetic neurons. Labels: A, a medullated fiber, axon, or dendrite, coming from cerebrospinal system and dividing into numerous branches on reaching a sympathetic ganglion. These branches connect with those of the cells, b, B, in the ganglion, and these cells send their non-medullated fibers, axons, or dendrites, to supply the viscera, C, C, C, C.

Diagram of the Relation between Cerebrospinal and Sympathetic Neurons

Diagram showing the relation of the cerebrospinal to the sympathetic neurons. Labels: A, a medullated…

Diagram of nervous system. Labels: a, a, cortex of cerebral hemispheres; b, b, cell body and dendrites of upper motor neuron, situated in cerebral cortex; b', axon of upper motor neuron, branching at its termination near the dendrites of lower motor neuron, situated in the ventral horn of gray matter in the spinal cord; B', axon of lower motor neuron passing to its termination in a voluntary muscle fiber B"; C, cell body and dendrites of supper sensory neuron, situated in the medulla oblongata; C'C', axons of upper sensory neurons, terminating in cortex; c, cell body of lower sensory neuron situated in the dorsal root ganglion; c''', dendrite of lower motor neuron, conducting impulses from the periphery to the central nervous system; c", long axon of lower sensory neuron, conducting impulses toward the brain; c', short axon of lower sensory neuron, conducting impulses direct to ventral horn. (For the sake of simplicity the connection with the cerebellum are omitted.)

Nervous System Diagram

Diagram of nervous system. Labels: a, a, cortex of cerebral hemispheres; b, b, cell body and dendrites…

Diagram of circulation. Labels: L, left side of heart; R, right side of heart; a,a,a arterial system; b,b, capillaries; c,c,c veins; Alim., alimentary canal; Liv., liver; p, portal vein; H,hepatic vein; Lymph., lymphatic duct and tributaries; Pulm., lungs; Pa, pulmonary artery; Pu, pulmonary vein.

Diagram of Circulation

Diagram of circulation. Labels: L, left side of heart; R, right side of heart; a,a,a arterial system;…

A Diagrammatic section across the body in the chest region. Labels: x, the dorsal tube, which contains the spinal cord; the black mass surrounding it is a vertebra; a, the gullet (esophagus), a part of the alimentary canal; h, the heart; sy, sympathetic nervous system; ll, lungs; the dotted lines around them are the pleurae; rr, ribs; st, the breastbone.

Section Across the Body in the Chest Region

A Diagrammatic section across the body in the chest region. Labels: x, the dorsal tube, which contains…

"The center of gravity, in any body or system of bodies is that point upon which the body, or system of bodies, acted upn only by gravity will balance itself in all positions." -Comstock 1850

Center of Gravity

"The center of gravity, in any body or system of bodies is that point upon which the body, or system…

"Suppose that A is the lever, B the fulcrum, D the weight to be raised, and C the power. Let D by considered three times as heavy as C, and the fulcrum three times as far from C as it is from D; then the weight and power will exactly balance each other out." -Comstock 1850

Simple lever system

"Suppose that A is the lever, B the fulcrum, D the weight to be raised, and C the power. Let D by considered…

"Suppose the weight, B to be sixteen pounds and suppose the fulrum to be placed so near it, as to be raised by the power A, of four pounds hanging equally distant from the fulcrum and the end of the lever. If now the power A be removed, and another of two pounds, C, be placed at te end of the lever, its force will be just equal to A, placed at the middle of the lever." -Comstock 1850

Simple Lever System

"Suppose the weight, B to be sixteen pounds and suppose the fulrum to be placed so near it, as to be…

"But let the fulcrum be moved along to the middle of the lever, with the weight of sixteen pounds still suspended to it, it would then take another weight of sixteen pounds, instead of two pounds, to balance it..." -Comstock 1850

Simple Lever System

"But let the fulcrum be moved along to the middle of the lever, with the weight of sixteen pounds still…

"...there is a system of pulleys represented, in which the weight is sixteen times the power." -Comstock 1850

Compound Pulley

"...there is a system of pulleys represented, in which the weight is sixteen times the power." -Comstock…

A small piece of bone, ground very thin and highly magnified. "If a bit of bone is still more magnified we find that very small cavities called lacunae lie between the lamelae; from each lacuna radiate many extremely fine tubes, the canaliculi, so that it looks like a small animal with a great many legs. The innermost canaliculi open into the Haversian canal of the system to which they belong, and those of various lacunae communicate with one another, so that a set of passages is provided through which liquid which transudes from the blood vessel in the Haversian canal can ooze through the bone." —Newell, 1900.

Section of Bone

A small piece of bone, ground very thin and highly magnified. "If a bit of bone is still more magnified…

"When any liquid is placed in one or more of several vessels communicating with each other, it will not come to rest until it stands at the same height inall of thw vessels. This principle is emobodied in the familiar expression 'Water seeks its level.' the principle is illustrated, on a large scale, in the system of pipes by which water is distributed in cities." -Avery 1895

Water Level in Multiple Connected Vessels

"When any liquid is placed in one or more of several vessels communicating with each other, it will…

"A complete telegraph system, displaying batteries, keys, receivers, relays and local batteries on both ends." -Avery 1895

Complete Telegraph System

"A complete telegraph system, displaying batteries, keys, receivers, relays and local batteries on both…

Diagram of the abdominal part of the alimentary canal (digestive system). Labels: C, the cardiac, and P, the pyloric end of the stomach; D, the duodenum; J, I, the convolutions of the small intestine; CC, the caecum with the vermiform appendix; AC, ascending, TC, transverse, and DC, descending colon; R, the rectum.

Alimentary Canal

Diagram of the abdominal part of the alimentary canal (digestive system). Labels: C, the cardiac, and…

"Electric-bell indicator for fishing [when installing home wiring systems]." —Croft 1915

Electric-bell Indicator

"Electric-bell indicator for fishing [when installing home wiring systems]." —Croft 1915

Diagram of the circulatory system, showing that it forms a single closed circuit with two pumps in it, represented by the right and left halves of the heart, which are separated in the diagram. Labels: ra and rv, right auricle and ventricle; la and lv, left auricle and ventricle; ao, aorta; sc, systemic capillaries; vc, vena cava, pa, pulmonary artery; pc, pulmonary capillaries; pv, pulmonary veins.

Diagram of the Circulatory System

Diagram of the circulatory system, showing that it forms a single closed circuit with two pumps in it,…

"A horse without machinery can not lift a weight; but he does it readily with the aid of the simple apparatus shown [here].." —Quackenbos 1859

Pulley System

"A horse without machinery can not lift a weight; but he does it readily with the aid of the simple…

"System of moveable pulleys. Each pulley has a separate rope attached to a fixed support at one end." —Quackenbos 1859

Movable Pulleys

"System of moveable pulleys. Each pulley has a separate rope attached to a fixed support at one end."…

Diagram illustrating the general arrangement of the nervous system.

Diagram of the Nervous System

Diagram illustrating the general arrangement of the nervous system.

The sympathetic nervous system.

The Sympathetic Nervous System

The sympathetic nervous system.

View of the nervous system of man, showing the nerve centers (brain and spinal cord) giving off nerves to supply the whole of the body.

The Nervous System

View of the nervous system of man, showing the nerve centers (brain and spinal cord) giving off nerves…

The labyrinth of the middle ear, which is composed of a system of fluid passages.

The Labyrinth of the Inner Ear

The labyrinth of the middle ear, which is composed of a system of fluid passages.

The sympathetic system of nerves.

The Sympathetic System of Nerves

The sympathetic system of nerves.