The reason why

Partly because of its original formation; but also because, _as the shell grows_, the opening is elongated; and thrown up, causing the spiral body of the shell to turn, and so t...

Because the skin is filled with very _minute pores_, which act as outlets for a portion of the water of the blood, that serves to _moisten and cool_ the surface of the body, and...

Vegetable oils and fats constitute, next to starch and sugar, the most important secretion of the vegetable creation. There are very few plants from which some amount of oil can...

Because they everywhere form the _food of the animal creation_. Without them, neither man nor beast could exist. Even the flesh-eating animals are sustained by them, since they...

It exists in various natural bodies in which carbon and oxygen are combined; it is evolved by the decomposition of numerous bodies called carbonates, in which carbon is united w...

Because the films of the bubbles constantly change in thickness, through the atoms from the upper part descending towards the bottom, and therefore the varying thickness of film...

Because the light and air would _act too powerfully for the young ear_; two leaves therefore join, and embrace the ear, and protect it until it has acquired strength, when they...

Because its smoothness enables it to work under ground _without the soil sticking to its coat_, by which its progress would be impeded. From soils of all kinds, the little worke...

Because, by the violence of the electric force, vast _fields of air are divided_; great volumes of air are _rarefied_; and _vapours_ are _condensed_, and thrown down as _rain_....

Another distinction is, that _heat expands all bodies_, and alters their atomic condition; while _light_, though usually attended by heat, does not display the same expansive fo...

A _breeze_ travels ten feet in a second; a _light gale_, sixteen feet in a second; a _stiff gale_, twenty-four feet in a second; a _violent squall_, thirty-five feet in a second...

Because, but for this, deep waters might be frozen through their whole depth. This would destroy the myriads of fish and other living things that inhabit the water. Parts of the...

Because it is found, by experiment and observation, that the air becomes _less dense_ in proportion to its altitude from the earth's surface. The gradual decrease of atmospheric...

Because a larger amount of heat has entered into it than can remain latent in water. The water therefore expands and rises in the form of vapour, or _water attenuated by heat_.

If we take a tuning fork, and hold it to the ear, we hear _no sound_. If we move it rapidly through the air, or if we blow upon it, it produces _no sound_; but if we _strike it_...

The fact that they are _bad conductors_ assists their ignition. The heat which would pass from particle to particle of the dense substance of iron, and be _conducted away_, accu...

Because the light which is reflected from them enters our eyes and produces images of their forms upon a membrane of nerves called the _retina_, just as images are produced upon...

Because, in the course of its formation, it has not only undergone change of condition and colour; but, if examined now by the microscope, it will be found to consist of million...

The mingling of the electricities of the earth and the air must be continually going on. But _lightning_ does not attend the phenomena, because all natural bodies, vapours, tree...

When rays of light fall _obliquely_ upon the surface of any _transparent medium_, they are slightly diverted from their course. This alteration of the course of the rays is call...

Because the air does not abstract the heat of the hand so rapidly as the water did, and the change in the degree of rapidity with which the heat is abstracted _produces a sensat...

Because they are encased in a hard covering upon which the gastric juice of animals takes no effect. This provision has been made by the Creator, _for the preservation of seeds_...

Light, according to Newton, is the effect of luminous particles which dart from the surfaces of bodies in all directions. According to this theory, the solar light which we rece...

Because the atoms of which our bodies are composed are _continually changing_. Those atoms that have fulfilled the purposes of nature are removed from the system, and, therefore...

The spinal cord is a long and large cord of nervous matter, which extends from the brain through a continuous tube formed by corresponding hollows in the bones of the back. It s...

Because the drops, in falling, _meet and unite_, and also gather _moisture_ in their descent. The greater the height from which a rain drop has descended, _the larger it is_, pr...

It is never found but in a state of combination; united with oxygen, it exists in _water_; with nitrogen, in _ammonia_; with chlorine, in _hydro-chloric acid_; with fluorine, in...

_Gutta-percha_ is an invaluable substance lately added to the list of known vegetable productions. It is obtained by cutting the bark of trees of the class called _Sapotacea_. I...

This definition has, in latter days, been held to be unsatisfactory, since there _are a few plants_ that are _supposed to feel_, and _a few animals_ that are supposed to have ev...

Professor Buckland, in his _Bridgewater Treatise_, speaking of the impressions of plants found in the coal mines, says; "The finest example I have ever witnessed is that of the...

[Verse: "Neither do men light a candle, and put it under a bushel, but on a candlestick; and it giveth light unto all that are in the house."--MATT. V.]

[Verse: "And God said, Let us make man in our own image, after our likeness; and let them have dominion over the fish of the sea, and over the fowl of the air, and over the catt...

[Verse: "But the wise answered saying, Not so; lest there be not enough for us and you: but go ye rather to them that sell, and buy for yourselves."--MATT. XXV.]

Because most food contains some particles that are indigestible, or that, if digested, are innutritious, and not necessary for the system. The _liver_ is the organ by whose secr...

Because, by breaking the stem, we rupture the vessels of the plant, and cause the nutritive fluid to escape. The sap of the plant is _analogous to the blood of man_, and the ves...

Because, if it is spun with _great force_, and its peg is _struck sharply_ against the pavement, _the wood is set in vibration_, and the surface of the top, repelling the air by...

Because in all probability, where the difference between the first and the ultimate form is considerable, the organs of the insect having to undergo great changes, it would suff...

The _angle_ of reflection is the angle which is formed by the returning rays of light, and a line perpendicular to the reflecting surface. It is always _equivalent_ to the angle...

_Refraction_ is the deviation of rays of light from their course through the interference of a _different_ medium; _reflection_ is the return of rays of light which, having fall...

Ligaments consist of bands and cords of a _tough_, _fibrous_, _and smooth substance_, by which the bones are bound together and held in their places, allowing them freedom to mo...

The inclosure of zone within zone is owing to the mode in which the wood is produced, and the position in which it is deposited. Wood is formed by the leaves during the growing...

A delicate thermometer, placed among the leaves and petals of flowers, will at once establish the fact, not only that flowers and plants have a temperature differing from that o...

Because, also, there is always a degree of atmospheric motion _upward_, caused by the _convection of heat_ from the earth's surface. And, although there must also be downward mo...

Because the tails of birds are used to guide them through the air, by a _kind of steerage_. When birds with long legs take to flight, they throw their legs behind, and they then...

Because it consists of a tube containing _quicksilver_, closed at one end and open at the other, so that the pressure of the air upon the open end balances the weight of the col...

Because the various creatures which God has created have different modes of life, and the forms of their bodies will be found to present _a perfect adaptation to the lives allot...

Because they radiate heat from _both their surfaces_. A piece of glass, laid horizontally over the earth, would radiate heat both _upwards_ and _downwards_. But on its lower sur...

Because the _tympanum_ of the ear _receives impressions from sounds_, and transmits those impressions to the brain in a similar manner to that in which the retina of the eye tra...

[Verse: "Behold there ariseth a little cloud from the sea, of the bigness of a man's hand. And it came to pass in the meantime, that the heaven was black with clouds and wind, a...

By passing the top of the finger along the wooden handle of the coffee-pot, until it reaches the point where the wood meets the metal. The wooden handle will be found to be _coo...

Heat is a principle in nature which, like light and electricity, is best understood by its _effects_. We popularly call that heat, which raises the temperature of bodies submitt...

Because oxygen, _by itself_, is incombustible. The wick of a candle, which retains the slightest spark, being immersed in oxygen, will instantly burst into a brilliant flame; an...

Thales, a Greek philosopher, observed that, by briskly rubbing _electrum_, it acquired the property of _attracting_ light particles of matter, which moved towards the amber, and...

Because by wetting the outer coat of their feathers before the rain falls, by sudden dashes of water over the surface, they _prevent the drops of rain from penetrating to their...

Because it subsists upon fish, generally of the smaller kind, and uses its pouch _as a net_ for catching them; the pouch also serves as a _paunch,_ in which the fish are stored,...

Because, having no wings, and being deficient in the active muscular powers of other spiders, they have been endowed with the power of spinning a web which is so light that it f...

Cartilage 32·17 parts Blood-vessels 1·13 " Carbonate of lime 11·30 " Phosphate of lime 51·04 " Fluate of lime 2·00 " Phosphate of Magnesia 1·16 " Soda, chloride of sodium 1·20 "...

Because the tongue is endowed with _gustatory_ nerves, having the function of _taste_ as their _special sense_, just as the _optic_, the _auditory_, and the _olfactory_ nerves,...

[Verse: "Behold, the nations are as a drop of a bucket, and are counted as the small dust of the balance: behold, he taketh up the isles as a very little thing."--ISAIAH XL.]

Because we are so created that the substances of our bodies are constantly undergoing change, and this resolving of solid matter into a gaseous form, is the plan appointed by ou...

There are _three_, viz., slow oxydation, _when little or no light is evolved_; a more rapid combination, _when the heat is so great as to become luminous_; and a still more ener...

Snow is _warm_ by virtue of its light and woolly texture. But it is also warm on account of its _whiteness_; for, had it been _black_, it would have _absorbed the heat of the su...

If we set a metal plate (or any other body, though metal is best for the experiment) before the fire, _rays of heat will fall upon it_. If we turn the plate at a slight angle, a...

196. _But if (as stated in the Lessons upon Conduction) metal is a better conductor of heat than stone or earthenware, why does not the metal jug conduct away the heat of the wa...

Because their inventors, after whom they are named, adopted a different system of _notation_, or _thermometrical marks_; and as their thermometers have been adopted by various c...

Knowledge enables us to understand that, in order to live healthily, we require to breathe fresh and pure air. It also tells us that animal and vegetable substances, undergoing...