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"Suppose a to be a long tube, with the piston b so nicely fitted to its inside, as to work air tight. If the lower end of the tube be dipped into water, and the piston drawn up by pulling at the handle c, the water will follow the piston so closely, as to be in contact with its surface, and apparently to be drawn up by the piston, as though the whole was one solid body. If the tube be thirty-five feet long, the water will continue to follow the piston, until it comes to the height of about thirty-three feet, where it will stop, and if the piston be drawn up still farther, the water will not follow it, but will remain stationary, the space from this height between the piston and the water, being left a void space or vacuum." —Comstock, 1850

Barometer

"Suppose a to be a long tube, with the piston b so nicely fitted to its inside, as to work air tight.…

"Hero's Machine. The generation of steam from water by the application of heat, and the mechanical force produced by this means, appear to have been understood at a very remote period; but their application to machinery devoted to the purposes of locomotion, is a discovery of recent date. The ingenious contrivances of early discoverers were devoted to objects of minor importance, as those of raising water and propelling smoke upwards." —Comstock, 1850

Hero's Machine

"Hero's Machine. The generation of steam from water by the application of heat, and the mechanical force…

"In 1629 Giovanni Branca, an Italian, contrived a machine which was employed for the various purposes of raising water, of sawing timber and pounding materials. His machine consisted of a wheel furnished with flat vanes around its circumference, like the boards of a paddle-wheel. Upon these vanes, steam was propelled from a close vessel, called an eolipile. A rotary motion was produced, and communicated to appropriate machinery. The results, however, of these and other discoveries made about this period, have never been rendered applicable to the purposes for which the modern steam engine is adapted." —Comstock, 1850

Brancas Engine

"In 1629 Giovanni Branca, an Italian, contrived a machine which was employed for the various purposes…

"Savery's Steam Engine. The adjoining figure illustrates the apparatus employed by Savory. It consists of a furnace and a boiler B; from the latter, two pipes, furnished with stop-cocks C, proceed to two steam vessels S, only one of which is shown in the figure, the other being immediately behind it. Into the bottom of each of these steam vessels is inserted a branching pipe, connected with a descending main pipe D, and an ascending main pipe A; each branching pipe is furnished with valves a, b, which open upwards, and prevent, by their action, the return of any water which may have been forced up through them." —Comstock, 1850

Savery Engine

"Savery's Steam Engine. The adjoining figure illustrates the apparatus employed by Savory. It consists…

"The simplest idea of a crank is that of a handle to a wheel; its action is familiarly illustrated in the process of drawing water from a well: the bent handle attached to the wheel is first pushed out, then pulled in the opposite direction, and thus a continued rotatory motion is produced upon an axle. The application of this principle to the steam engine, and the variations of pressure on the crank of a steam enginre, may be conveniently illustrated by curves." —Comstock, 1850

Crank

"The simplest idea of a crank is that of a handle to a wheel; its action is familiarly illustrated in…

"The refraction of water is beautifully proved by the following simple experiment. Place an empty cup, with a shilling on the bottom, in such a position that the side of the cup will just hide the piece of money from the eye. Then let another person fill the cup with water, keeping the eye in the same position as before. As the water is poured in, the shilling will be come visible, appearing to rise with the water. The effect of the water is to bend the ray of light coming from the shilling, so as to make it meet the eye below the point where it otherwise would. Thus the eye could not see the shilling in the direction of c, since the line, of vision is towards a, and c is hidden by the side of the cup. But the refraction of the water bends the way downwards, producing the same effect as though the object had been raised upwards, and hence it becomes visible." —Comstock, 1850

Cup and Shilling

"The refraction of water is beautifully proved by the following simple experiment. Place an empty cup,…

"Let m be the Moon, and E the Earth covered with water. As the Moon passes round the Earth, its solid and fluid parts are equally attracted by her influence according to their densities; but while the solid parts are at liberty to move only as a whole, the water obeys the slightest impulse, and thus tends towards the Moon where her attraction is the strongest. Consequently, the waters are perpetually elevated immediately under the Moon. If, therefore, the Earth stood still, the influence of the Moon's attraction would raise the tides only as she passed round the Earth. But as the Earth turns on her axis every 24 hours, and as the waters nearest the Moon, as at a, are constantly elevated, they will, in the course of 24 hours, move round the whole Earth, and consequently from this cause there will be high water at every place once in 24 hours." —Comstock, 1850

Tides

"Let m be the Moon, and E the Earth covered with water. As the Moon passes round the Earth, its solid…

"The elevation of the tides at c and d is produced by the causes already explained; but their elevation is not so great as normal, since the influence of the Sun acting in the direction a b, tends to counteract the Moon's attractive influence. These small tides are called neap tides, and happen only when the Moon is in her quadartures." —Comstock, 1850

Neap Tides

"The elevation of the tides at c and d is produced by the causes already explained; but their elevation…

"Mercury manometer for recording blood-pressure. d g, glass U-tube partly filled with mercury. In one limb is borne a float, e, bearing a recording device f; the other limb is filled with a suitable liquid and connected water-tight with the heart end of a divided artery b, by means of glass connection a. Changes in the mercury level indicated changes of arterial pressure." —Martin, 1917

Manometer

"Mercury manometer for recording blood-pressure. d g, glass U-tube partly filled with mercury. In one…

"Eggs of mosquitoes. A, Culex; B, Anopheles photographed on the water, natural size." —Davison, 1906

Mosquito Eggs

"Eggs of mosquitoes. A, Culex; B, Anopheles photographed on the water, natural size." —Davison,…

"Pea weevil; adult. The pea weevil (Bruchus) is often found in peas in its larval state during summer and autumn, as a pupa in winter, and in the adult form in late spring, when it comes forth to lay its eggs on the pods of the growing peas. To find the weevil in the fall, soak peas in water for a day." —Davison, 1906

Pea Weevil

"Pea weevil; adult. The pea weevil (Bruchus) is often found in peas in its larval state during summer…

"Pea weevil; pupa. The pea weevil (Bruchus) is often found in peas in its larval state during summer and autumn, as a pupa in winter, and in the adult form in late spring, when it comes forth to lay its eggs on the pods of the growing peas. To find the weevil in the fall, soak peas in water for a day." —Davison, 1906

Pea Weevil

"Pea weevil; pupa. The pea weevil (Bruchus) is often found in peas in its larval state during summer…

"The water fleas just visible to the naked eye are present in nearly all waters and become very abundant in stagnant water." —Davison, 1906

Daphnia

"The water fleas just visible to the naked eye are present in nearly all waters and become very abundant…

Babcock and Wilcox water-tube boiler fitted with superheaters

Water-tube Boiler

Babcock and Wilcox water-tube boiler fitted with superheaters

Stirling Water-tube boiler

Water-tube Boiler

Stirling Water-tube boiler

Yarrow Water-tube Boiler

Yarrow Water-tube Boiler

Yarrow Water-tube Boiler

Babcock and Wilcox Water-tube Boiler, longitudinal section

Babcock and Wilcox Water-tube Boiler

Babcock and Wilcox Water-tube Boiler, longitudinal section

Babcock and Wilcox Water-tube Boiler, section at AB-front elevation

Babcock and Wilcox Water-tube Boiler

Babcock and Wilcox Water-tube Boiler, section at AB-front elevation

"AB is a strong metal tube, closed at the lower end, and carrying at the upper a bent pipe for admitting the compressed gas and a stop-cock R pierced with holes in a T form. DE and FG are two graduated glass tubes communicating at their lower ends by a narrow passage in the metal block to which they are hermetically fixed. DE and AB Also communicate at the upper ends by a passage in a metal piece attached bermetically to them. By the stop-cock R', having radial holes at right angles to each other, DE can communicate either with AB or with the atmosphere at O; and by the stop-cock R'' it can communicate either with FG or with the open air. The three tubes are surrounded by a cylinder MM' containing water to keep the temperature constant. The tube AB is filled with the compressed gas whose pressure is to be ascertained. Mercury is poured into FG till it fills DE and runs out at O." —The Encyclopedia Britannica, 1903

Regnaults Manometer

"AB is a strong metal tube, closed at the lower end, and carrying at the upper a bent pipe for admitting…

"For a laboratory microscope, the pattern represented here has been found very convienient, —the framework being of mahogany or other hard wood, the stage being large enough to admit a dissection or carry a water-trough of considerable size, and the bent armthat carries the "powers" being made capable of reversion, so as to permit the use of lenses of very long as well as of very short focus." —The Encyclopedia Britannica, 1903

Microscope

"For a laboratory microscope, the pattern represented here has been found very convienient, —the…

A white or brown arthropoda. Has a pair of cirri, which form a net used to scoop food particles out of the water and into its mouth. Usually very sharp around the opening.

Barnacles

A white or brown arthropoda. Has a pair of cirri, which form a net used to scoop food particles out…

A scene of turtles and water.

Turtles and Water

A scene of turtles and water.

A hollow sphere of ball attached to the end of a lever, which turns the stop—cock of a water pipe and regulates the supply of water.

Ball Cock

A hollow sphere of ball attached to the end of a lever, which turns the stop—cock of a water pipe…

A hand-box which protects plants from wind and water running into it.

Hand-box

A hand-box which protects plants from wind and water running into it.

A Thornycroft-Shulz water-tube boiler

Boiler

A Thornycroft-Shulz water-tube boiler

The larva is curious little creatures, living under water in rather swiftly flowing streams, clinging to rocks, sticks, or logs, and feeding upon vegetable matter.

Buffalo Gnat Larva

The larva is curious little creatures, living under water in rather swiftly flowing streams, clinging…

The larva are curious little creatures, living under water in rather swiftly flowing streams, clinging to rocks, sticks, or logs, and feeding upon vegetable matter.

Buffalo Gnat Pupa

The larva are curious little creatures, living under water in rather swiftly flowing streams, clinging…

The larvae are elongated, somewhat flattened creatures, some living in the soil, some in water, and some in marshes, preying upon what ever comes in their way.

Horse Fly Larva

The larvae are elongated, somewhat flattened creatures, some living in the soil, some in water, and…

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A type of buoy

Buoy

A type of buoy

A backwoods girl

Girl

A backwoods girl

Series of sepals, petals, and stamens of White Water-Lily, showing the transitions.

White Water-Lily

Series of sepals, petals, and stamens of White Water-Lily, showing the transitions.

A scene from the story, "The Drop of Water."

The Drop of Water

A scene from the story, "The Drop of Water."

Seed of White Water-Lily, enclosed in its aril.

White Water-Lily

Seed of White Water-Lily, enclosed in its aril.

Magnified view of some of a simple fresh water Alga, the Tetraspora lubrica, each sphere of which may answer to an individual plant.

Alga

Magnified view of some of a simple fresh water Alga, the Tetraspora lubrica, each sphere of which may…

A detached cell, with rhaphides being forced out, as happens when put in water.

Detached Cell

A detached cell, with rhaphides being forced out, as happens when put in water.

Also known as the Seventeen-Year Locust, derives its specific name from the fact that it makes its appearance in certain districts at stated intervals of seventeen years in immense numbers, when the millions of them, swarming on the forest and fruit trees, almost deafen the observer with their trilling calls to the female, and form an abundant feast to the swine, fowls, and wild animals on the land, and if near a river or lake, to the fishes in the water.

Cicada Septendecim

Also known as the Seventeen-Year Locust, derives its specific name from the fact that it makes its appearance…

A girl standing in the ocean crying while a crab looks at her.

Girl in Ocean

A girl standing in the ocean crying while a crab looks at her.

A little girl on a sail boat holding onto the main sail.

Little Girl Sailing

A little girl on a sail boat holding onto the main sail.

A little girl sitting in a hamock above water looking at a frog.

Girl Sitting In A Hamock

A little girl sitting in a hamock above water looking at a frog.

River with two boats on it. Scenery that of the north east.

Portait of a River

River with two boats on it. Scenery that of the north east.

An outdoor scene

Great Outdoors

An outdoor scene

When the remains of an animal or plant are exposed to the air or buried in dry earth, they generally decompose and pass off almost entirely as gasses; but when buried under water or in damp earth, their preservation is probable. Therefore, the species most likely to become fossilized are those living in water or marshes, or in the neighborhood of water or marshes.

Fossil Encrinite

When the remains of an animal or plant are exposed to the air or buried in dry earth, they generally…

In this age the animals and plants begin to resemble existing species. The age is characterized mainly by the preponderance of reptiles, many of which were very large, as, for example, the <em>plesiosaurus</em>, an animal with a long, snake-like neck and a huge body, or the <em>ichthyosaurus</em>, with a head like a crocodile and short neck and large body. Both of these animals were furnished with fin-like paddles, and lived in water.

Reptiles

In this age the animals and plants begin to resemble existing species. The age is characterized mainly…

The Amazon River is the largest, most voluminous river on earth, having a greater total flow than the next six largest rivers combined.

Amazon River

The Amazon River is the largest, most voluminous river on earth, having a greater total flow than the…

Fiords are valleys that were deeply eroded by slowly moving masses of ice called glaciers, subsequently partially submerged.

Fiords on Norway Coast

Fiords are valleys that were deeply eroded by slowly moving masses of ice called glaciers, subsequently…

A collage of different water scenes.

Water, Collage of

A collage of different water scenes.

A spring is a point where groundwater flows from the ground, and is thus where the aquifer surface meets the ground surface

Origin of Springs

A spring is a point where groundwater flows from the ground, and is thus where the aquifer surface meets…