Any four-point on a curve of the second order and the four-side formed by the tangents at these points stand in this relation that the diagonal points of the four-point lie in the diagonals of the four-side.

Second Order Curve Tangents

Any four-point on a curve of the second order and the four-side formed by the tangents at these points…

"A genus of Old World bulbous plants belonging to the order Lilacæ." —Finley, 1917

Scilla

"A genus of Old World bulbous plants belonging to the order Lilacæ." —Finley, 1917

"The prunella, or self-heal, is a genus of hardy perennial, herbaceous plants belonging to the order Labiatae."—Finley, 1917

Prunella

"The prunella, or self-heal, is a genus of hardy perennial, herbaceous plants belonging to the order…

"Star of Bethlehem, or Ornithogalum, a genus of bulbous plants belonging to the order Liliacae."—Finley, 1917

Star of Bethlehem

"Star of Bethlehem, or Ornithogalum, a genus of bulbous plants belonging to the order Liliacae."—Finley,…

"A former genus of herbaceous plants belonging to the order Caryophylacae, and now included in the genus Alsine."—Finley, 1917

Greater stitchwort

"A former genus of herbaceous plants belonging to the order Caryophylacae, and now included in the genus…

In order to rid water of impurities, it is required to boil water, then condense the steam to make it fit for chemical use.

Distilling Apparatus

In order to rid water of impurities, it is required to boil water, then condense the steam to make it…

Represents the relation between the tetragonal bipyramid of the first order when the indices are {111}.

Tetragonal Bipyramids of the First Order

Represents the relation between the tetragonal bipyramid of the first order when the indices are {111}.

Represents the relation between the tetragonal bipyramid of the first order when the indices are {111}.

Tetragonal Bipyramids of the Second Order

Represents the relation between the tetragonal bipyramid of the first order when the indices are {111}.

"...a combination of a bipyramid of the first order with a ditetragonal bipyramid and the prism of the second order." -The Encyclopedia Britannica 1910

Combination of a bipyramid and prism

"...a combination of a bipyramid of the first order with a ditetragonal bipyramid and the prism of the…

"...a combination of two bisphenoids (P and P'), two bipyramids of the second order (b and c), and the basal pinacoid (a)." -The Encyclopedia Britannica 1910

Crystal of Chalcopyrite

"...a combination of two bisphenoids (P and P'), two bipyramids of the second order (b and c), and the…

"...a combination of tetragonal prism of the first order with a tetragonal bipyramid of the third order and the basal pinacoid." -The Encyclopedia Britannica 1910

Crystal of Fergusonite

"...a combination of tetragonal prism of the first order with a tetragonal bipyramid of the third order…

"...represents a crystal of dioptase with the fundamental rhombohedron (r) and the hexagonal prism of the second order (m) combined with the rhombohedron (s)." -The Encyclopedia Britannica 1910

Crystal of Dioptase

"...represents a crystal of dioptase with the fundamental rhombohedron (r) and the hexagonal prism of…

"Hexagonal prism of the first order, consisting of six faces also parallel to the hexad axis, but perpendicular to the other set of three vertical planes of symmetry." -The Encyclopedia Britannica 1910

Hexagonal Prism of the First Order

"Hexagonal prism of the first order, consisting of six faces also parallel to the hexad axis, but perpendicular…

Two alveoli of the lung, highly magnified. Alveoli are cavities which are honeycombed with bulgings in order to increase the surface area exposed to air and covered by capillaries. Labels: b,b, bulgings of the alveoli, a, a.

Two Alveoli of the Lung

Two alveoli of the lung, highly magnified. Alveoli are cavities which are honeycombed with bulgings…

"Illustrating the principle of Siemens' drum winding. In order to make the winding and connections clear, one coil and the commutator is shown assumbled, although the latter is not put in place until after all the sections have been wound, the ends of the wires temporarily twisted together until all can be soldered to the risers. the cores of these early machines were of wood, overspun circumferentially with iron wire before receiving the longitudinal copper windings." -Hawkins, 1917

Siemens' Drum Winding

"Illustrating the principle of Siemens' drum winding. In order to make the winding and connections clear,…

"In order that the successive wheels should revolve in the same time, and their circumfrences should be just equal to the length of rope passing between them...By this construction, although the length of rope passing over each was different, yet their revolutions are equal, both with respect to time and number." -Comstock 1850

White's Pulley

"In order that the successive wheels should revolve in the same time, and their circumfrences should…

"The inner or primary bow is much brighter than the other; the outer or secondary bow has the order of colors revered, as indicated." -Avery 1895

Secondary Rainbow

"The inner or primary bow is much brighter than the other; the outer or secondary bow has the order…

The salivary glands. One side of the lower jaw has been removed, and the face dissected, in order to show the salivary glands on the right side.

Salivary Glands

The salivary glands. One side of the lower jaw has been removed, and the face dissected, in order to…

"Let the are of the piston a be 20 square inches; of b, 7 sq. in.; of c, 1 sq. in.; of d, 6 sq. in.; of e, 8 sq. in; and of f, 4 sq. in. If... a force of five pounds be applied at c, a pressure of five pounds per square inch will be transmitted in all directions, and in order that there shall be no movement, the required pressure must be applied by all the other pistons in proportion." —Hallock 1905

Water Pressure Demonstration

"Let the are of the piston a be 20 square inches; of b, 7 sq. in.; of c, 1 sq. in.; of d, 6 sq. in.;…

"We have an example of resultant motion in a boat which a person attempts to row north across a river, while the tide carries it to the east. Each force produces the same effect as if acted alone; and the boatman, when he has crossed the river, will find himself neither due north nor due east of the point from which he started, but northeast of it." —Quackenbos 1859

Resultant Motion with Boat

"We have an example of resultant motion in a boat which a person attempts to row north across a river,…

Diagrammatic view from before of the spinal cord and medulla oblongata, including the roots of the spinal and some of the cranial nerves, and on one side of the gangliated chain of the sympathetic. The spinal nerves are enumerated in order on the right side of the figure. Labels: Br, brachial plexus; Cr, anterior crural, O, obturator, and Ss, great sciatic nerves, coming off from lumbo-sacral plexus; x, x, filum terminale; a,b,c, superior, middle, and inferior cervical ganglia of the sympathetic, the last united with the first thoracic, d; d', the eleventh thoracic ganglion; l, the twelfth thoracic (or first lumbar); below ss, the chain of sacral ganglia.

Spinal Cord

Diagrammatic view from before of the spinal cord and medulla oblongata, including the roots of the spinal…

A vertical section of the head and neck through the mesial line, in order to show the opening of the Eustachian tube and its relation to the pharynx.

A Vertical Section of the Head and Neck

A vertical section of the head and neck through the mesial line, in order to show the opening of the…

Illustrations to show quadrilaterals with lines joining the midpoints of the sides of any quadrilateral, taken in order.

Quadrilaterals With Lines Joining Midpoints

Illustrations to show quadrilaterals with lines joining the midpoints of the sides of any quadrilateral,…

Illustrations to show trapezoids with lines joining the midpoints of the sides of any quadrilateral, taken in order.

Trapezoids With Lines Joining Midpoints

Illustrations to show trapezoids with lines joining the midpoints of the sides of any quadrilateral,…

Structure of the chest, showing the framework of the bones which are connected together chiefly by muscles. It is important to understand the structure of the chest in order to understand how the movements of the chest are made in inspiration and expiration. The spinal column <em>b,b</em> is the grand pillar that supports this barrel-shaped framework. The ribs <em>c, c, c</em> are fastened very strongly by ligaments to the spinal column. They are 2 in number, 12 on each side and extend round towards the breast bone (sternum) <em>a</em> in front.

Structure of the Chest

Structure of the chest, showing the framework of the bones which are connected together chiefly by muscles.…

The lenses and humors of the eye must be very exactly arranged, in order that the sight may be perfect. They must be so arranged that the images of the objects shall be formed distinctly on the retina. In nearsighted persons the lenses and humors are so arranged as to make the rays that form the images from together too quickly, before they reach the retina, as shown in the figure.

Nearsighted Vision

The lenses and humors of the eye must be very exactly arranged, in order that the sight may be perfect.…

Leaves - compound (odd-feathered, but with the odd leaflet often dwarfed or broken off; leaflets, twenty-one to forty-one); alternate; edge of the leaflets entire, with one or two coarse, blunt teeth at each side of their base. Outline - of leaflet, long egg-shape or lance-shape. Apex - taper-pointed. Base, squared, or heart-shaped. Leaf/Stem - smooth, round, swollen at base. Leaflet/Stems - smooth and short. Leaf - one and a half to six feet long. Leaflets variable, usually about six inches by two and a quarter, rather smooth and thin. Bark - of the trunk, smooth and brown; the new shoots marked with whitish dots. Flowers - in long bunches at the ends of the branches; greenish, and of very disagreeable odor. June, July. Seeds - flat, at the centre of greenish and sometimes pink-tinged wings, in large, loose clusters. October. Found - common in cultivation, and to some extent naturalized. General Information - A large, showy tree (sixty to seventy feet high) of remarkable vigorous and rapid growth. It is a native of China. A Jesuit missionary sent its seeds in 1751 to England. In 1784 it was brought from Europe to the United States, and started near Philadelphia. Also about 1804 it was brought to Rhode Island from South America. But the source of most of the trees now found abundantly in the region of New York is Flushing, Long Island, where it was introduced in 1820. It has been a great favorite, and would deserve to be so still were it not for the peculiar and disagreeable odor of its flowers. Ailanthus, from a Greek word meaning "tree of heaven." Ailanthus - This spelling of the name should rule because so given by its author, although, etymologically, Ailantus would be correct, the native Amboyna name being "Aylanto."

Genus Ailanthus, Desf.

Leaves - compound (odd-feathered, but with the odd leaflet often dwarfed or broken off; leaflets, twenty-one…

View of labyrinth on the left side, open throughout, in order to show its structure -- enlarged.

Labyrinth of the Ear on the Left Side

View of labyrinth on the left side, open throughout, in order to show its structure -- enlarged.

In changing the compass from a small to large radius, hold the legs together with one hand and spin the nut with the other, in order to save wear on the threads.

Adjusting the Compass

In changing the compass from a small to large radius, hold the legs together with one hand and spin…

A poster with important images and facts from the period of glory (500-431 B.C.).

Greece Poster

A poster with important images and facts from the period of glory (500-431 B.C.).

The Golden Fleece is military decoration of Europe.

The Golden Fleece

The Golden Fleece is military decoration of Europe.

The White Elephant is military decoration of Europe.

The White Elephant

The White Elephant is military decoration of Europe.

St. Michael and St. George are military decorations of Europe.

St. Michael and St. George

St. Michael and St. George are military decorations of Europe.

The Legion of Honor is a military decoration of Europe.

The Legion of Honor

The Legion of Honor is a military decoration of Europe.

The Bath is a military decoration of Europe.

The Bath

The Bath is a military decoration of Europe.

The Garter is a military decoration of Europe.

The Garter

The Garter is a military decoration of Europe.

St. Isabella is a military decoration of Europe.

St. Isabella

St. Isabella is a military decoration of Europe.

The Black Eagle is a military decoration of Europe.

The Black Eagle

The Black Eagle is a military decoration of Europe.

The line of characters and their actions in order for the pig to go over the stile.

Old Woman and Animals

The line of characters and their actions in order for the pig to go over the stile.

A boy visits an old woman.

Old Woman and Boy

A boy visits an old woman.

The topographical map is used to construct a hasty profile in order to determine visibility.

Hasty Profile

The topographical map is used to construct a hasty profile in order to determine visibility.

The measurements in order to make a box kite.

Box Kite

The measurements in order to make a box kite.

Illustration of the three bears with three chairs that can be used to write mathematics story problems involving comparison, taller, shorter, highest, lowest, etc..

Three Bears and Chairs

Illustration of the three bears with three chairs that can be used to write mathematics story problems…

Illustration of two children holding rulers that can be used to write mathematics story problems involving comparison, taller, shorter, highest, lowest, etc.

Children Holding Rulers

Illustration of two children holding rulers that can be used to write mathematics story problems involving…

Illustration of a child measuring with rulers that can be used to write mathematics story problems involving comparison, measurement, etc.

Child Holding Rulers

Illustration of a child measuring with rulers that can be used to write mathematics story problems involving…

Illustration of children holding rulers that can be used to write mathematics story problems involving comparison, taller, shorter, highest, lowest, etc.

Children Holding Rulers

Illustration of children holding rulers that can be used to write mathematics story problems involving…

Illustration of children holding number cards that can be used to write mathematics story problems involving addition, subtraction, and comparison.

Children Holding Number Cards

Illustration of children holding number cards that can be used to write mathematics story problems involving…

Illustration of children playing darts that can be used to write mathematics story problems involving addition, subtraction, and comparison.

Children Playing Darts

Illustration of children playing darts that can be used to write mathematics story problems involving…

Illustration of children sitting on a bench and standing that can be used to write mathematics story problems involving comparison, taller, shorter, highest, lowest, counting, etc.

Children On A Bench

Illustration of children sitting on a bench and standing that can be used to write mathematics story…

Side view of the eyeball. Labels: a, the eyeball, and b,b, are the upper and lower sides. Now in order to prevent dust and other bodies from working their way between the ball and the lid, through passages at c,c, into the socket of the eye where they would excite great inconvenience and pain, we find the common skin of the eye lids d,d, after covering their edges turn in a little way between the lid and the ball, and then turn back and are reflected over the surface of the cornea; where, to prevent the obstruction of vision, it becomes perfectly transparent.

Side View of the Eyeball

Side view of the eyeball. Labels: a, the eyeball, and b,b, are the upper and lower sides. Now in order…

An illustration of a commercial draft for $122.50. "A commercial draft is a written order by which one person directs a second person to pay a specified sum of money at a stated time, through a bank."

Commercial Draft

An illustration of a commercial draft for $122.50. "A commercial draft is a written order by which one…

A cat grinding coffee by order of his master, in the story "How Cats Came to Purr."

Cat and Mater

A cat grinding coffee by order of his master, in the story "How Cats Came to Purr."

Conflict with a rattlesnake. Caption below illustration: "The snake when about a yard distant, made a violent spring. Jervas caught it in his right hand, directly under his head. He squeezed it with all his power. Its eyes almost started out of its head. It lashed its body on the ground, at the same time rattling loudly."

Conflict with a Rattlesnake

Conflict with a rattlesnake. Caption below illustration: "The snake when about a yard distant, made…

The Sea horse is a remarkable fish found near our South American coasts. It belongs to the singular order known as Lophobranch.

The Sea horse

The Sea horse is a remarkable fish found near our South American coasts. It belongs to the singular…

A large insect of the order Homptera.

Cicada

A large insect of the order Homptera.

"The castor oil plant belongs to an order whose affinities have not yet been accurately limited by botanists; but it is supposed to comprise at least one thousand five hundred species." -Lupton

The Castor Oil Plant

"The castor oil plant belongs to an order whose affinities have not yet been accurately limited by botanists;…

"A genus of extinct flying reptiles of the order Pterosauria, found in the Jura Limestone formation, in the Lias at Lyme-Regis, in the Oolite slate of Stonefield." -Marshall

Pterodactyl

"A genus of extinct flying reptiles of the order Pterosauria, found in the Jura Limestone formation,…

(1491-1556) Spanish founder of the Society of Jesus.

Saint Ignatius of Loyola

(1491-1556) Spanish founder of the Society of Jesus.

A strong-scented herbaceous plant of the genus Ruta, nat. order Rutacae, a native of S. Europe, but also cultivated in gardens in the United States.

Rue Plant

A strong-scented herbaceous plant of the genus Ruta, nat. order Rutacae, a native of S. Europe, but…

The name given to various animals included in the class Amphibia and in the order Urodela of that class. The salamanders may be divided into the land salamander and the water salamanders.

Cold Blooded Salamander

The name given to various animals included in the class Amphibia and in the order Urodela of that class.…