Fig. 74.—GLOW-WORM USING HIS BRUSH.
Fig. 74.—GLOW-WORM USING HIS BRUSH.
1127.Why has the glow-worm a brush attached to its tail?
Because it is necessary to keep its back very clean, thatthe light which its body emits may not be dimmed.
1128.Why does the glow-worm emit a light?
Because the female glow-worm is without wings, but the male is a winged insect. The female, therefore, is endowed with the power of displaying a phosphorescent light. The light is only visible bynight, but it is, nevertheless, beautifully adapted for the purpose stated, because themale is a night-flying insect, and never ventures abroad by day.
"They that go down to the sea in great ships, that do business in great waters these see the works of the Lord, and his wonders in the deep."—Psalm cvii.
There exists some difference of opinion between naturalists upon the uses of the light of a glow-worm; there are some who doubt that it is exhibited to attract the flying insect. The objectors, however, offer no explanation of the luminous properties of the worm. Sir Charles Bell says the preponderance of the argument is decidedly in favour of the explanation we have given.
1129.Why does not the iris of the fish's eye contract?
Because the diminished light in water isnever too strong for the retina.
1130.Why is the eye of the eel covered with a transparent horny covering?
Because, as the eel lives in holes, and pushes its head into mud, and under stones, &c., it needed such a covering todefend the eye.
1131.Why is the whale provided with an eye, having remarkably thick and strong coats?
Because, when he is attacked by the sword-fish and the shark, he is almost helpless against his enemies, as they fix themselves upon his huge carcase. He therefore dives with them down to a depth where the pressure of the water is so great that they cannot bear it. The eye of the whale is expressly organisedto bear the immense pressure of extreme ocean depths, without impairing the sight.
1132.Why have fishes no eyelids?
Because the water in which they swim keeps their eyes moist. Eyelids would therefore beuseless to them.
1133.Why have fishes the power of giving their eye-balls very sudden motion?
Because, having no eyelids (such organs being unnecessary to keep their eyes moist), they still need the power of freeing their eyes from the contact of foreign matters; and this is secured to them by the power they have of giving the eyeball a very rapid motion, which causes reaction in the fluid surrounding it, andsweeps the surface.
This motion may frequently be seen in the eyes of fishes, in glass globes.
"And God made the beast of the earth after his kind, and cattle after their kind, and everything that creepeth upon the earth after his kind: and God saw that it was good."—Genesis i.
1134.Why is the lachrymal secretion of the horse's eye thick and glutinous?
Because, as his eye is large, and constantly exposed to dust on journeys, it is provided with aviscid secretion, which cleanses the eye, and more instantly and securely removes the dust, than awaterysecretion would.
1135.Why does the lower bill of the sea-crow project beyond the upper one?
Because the bird obtains his food byskimming along the water, into which he dips his bill, and lifts his food out.
1136.Why do the mandibles of the cross-bill overlap each other?
Because the bird requires a peculiar bill, to enable it tosplit seeds into halves, and to tear the open cones of the fir-tree.
1137.Why are the tails of fishes so much larger than their fins?
Because their tails are theirchief instruments of motion, while their fins are employed simply to direct their progress, and steady their movements.
1138.Why have oxen, and other quadrupeds a tough ligament called the "pax-wax," running from their backs to their heads?
Because their heads are of considerable weight; and having frequent occasion to lift them, they are provided with an elastic ligament, which is fastened at the middle of their backs, while its other extremity is attached to the head. This enables them to raise their heads easily; otherwise the effort to do so would be a work of great labour. To the horse, the pax-wax acts as a natural bearing-rein, assisting it to hold its head in that position which adds to the grace and beauty of the animal.
In carving beef, this ligament may be seen passing along the vertebræ of the neck, the chuck, and the fore ribs.
"He shall feed his flock like a shepherd; he shall gather the lambs with his arm, and carry them in his bosom, and shall gently lead those that are with young."—Isaiah xl.
1139.Why have the females of the kangaroo and opossum tribes pouches, or pockets, formed in the skin of their breasts for the reception of their young?
Because their young ones are remarkablysmall and helpless; in fact, more so than those of any other animal of equal proportions. Besides which, the full grown animals have very long hind-legs, and they progress by a series of extraordinary leaps. It would consequently be impossible for their helpless young ones to follow them: God has therefore given to female kangaroos and opossums curious pockets,formed out of their own skin, in which they place their little young ones, and bear them through their surprising leaps with the greatest ease and safety.
1140.What is the difference between an animal, a plant, and a mineral?
The great naturalist, Linnæus, used to say that animalsgrow,live, andfeel; plantsgrowandlive; and mineralsgrow.
Animals are here defined to enjoythreeconditions of existence; plantstwoconditions; and mineralsonecondition.
This definition has, in latter days, been held to be unsatisfactory, since thereare a few plantsthat aresupposed to feel, anda few animalsthat are supposed to have evenless feelingthan thesensitive plantsalluded to.
The concise definition by Linnæus, nevertheless, is true, as far as regards avast majorityof the bodies constituting the three great kingdoms of nature. And it may be sufficient to say that
Animals—grow, live, feel, and move.
Plants—grow and live.
Minerals—grow, by the addition of particles of inorganic matter.
If we now state the few exceptions that are admitted to this definition, we shall bring the explanation as near to the truth, as the present state of knowledge will permit.
"And God said, Behold, I have given you every herb bearing seed, which is upon the face of all the earth, and every tree, in the which is the fruit of a tree, yielding seed; to you it shall be for meat."—Genesis i.
1141.Why is it understood that some plants feel?
Because thesensitive plantcloses its leaves on being touched; theVenus's fly trapcloses its leaves upon flies that alight upon them; otherscloseupon the approach of rain, and at sunset, andopenat sunrise, and turn towards the sun during its daily transit.
1142.Why is it understood that some plants move?
Because certainsea-weedsthrow off undeveloped young plants, which move through the water by the aid of finecilia, or muscular hairs, until they find a suitable place upon which to attach themselves.
The roots of plants will penetrate through the ground in the direction of water, and of favourable soil.
1143.Of what elementary substances are plants composed?
Of carbon, oxygen, hydrogen, and nitrogen.
1144.Whence do plants derive those substances?
From the air, the earth, and water.
1145.How do plants obtain carbon?
They obtain it chiefly from the air, in the form ofcarbonic acid gas. The carbon, of the carbonic acid gas, which is thrown out by the breath of animals, and by other processes in nature, isabsorbed by the leaves of plants, and theoxygenwhich had united with the carbon to form thecarbonic acid gas, is again set free for the use of animals.
1146.How do plants obtain oxygen?
They obtain it from theatmospheric air. But as they do not require a large amount of oxygen for their own use,they throw off the amount which is in excess, after having separated it from the other elements with which it was combined when taken up by them. From the humble blade of grass, to the stately tree of the forest, plants operate to purify the air, and to correct and counteract the corruption of the air, by the myriads of animals inhabiting the earth.
It has been generally stated that plants in rooms purify the air by absorbing carbonic acidby day, and releasing a part of the oxygen; but that, as the presence of light is necessary to produce this action, they do not restore oxygen tothe air, by night, but, on the contrary, give off carbonic acid gas. Therefore it has been stated that plants in rooms by night are unhealthy. Mr. Robert Hunt, one of the ablest chemists of the present time, makes the following remarks upon this subject in his "Poetry of Science:"—
"The heavens declare the glory of God: and the firmament showeth his handy work. Day unto day uttereth speech, and night unto night showeth knowledge."—Psalm xix.
"The power of decomposing carbonic acid is a vital function which belongs to the leaves and bark. It has been stated, on the authority of Leibig, that during the night the plant acts only as a mere bundle of fibres—that it allows of the circulation of carbonic acid and its evaporation, unchanged. In his eagerness to support his chemical hypothesis of respiration, the able chemist neglected to enquire if this was absolutely correct. The healthy plant never ceases to decompose carbonic acid during one moment of its existence; but during the night, when the excitement of light is removed, and the plant reposes, its vital powers are at their minimum of action, and a much less quantity is decomposed than when a stimulating sun, by the action of its rays, is compelling the exertion of every vital function."
In hot, swampy countries, where vegetation is very rapid, and the soil loaded with decomposing carbonic matter, the plants absorb more carbonic acid than they require, and theythenevolve carbonic acid gas from their leaves. Hence such climates as the West Indies are injurious tolife, though favourable tovegetation.
1147.How do plants obtain hydrogen?
They obtainhydrogenin combination withoxygenin water, and withnitrogen, in the form ofammonia, as which it exists in animal manures.
1148.How do plants obtain nitrogen?
From theatmospheric air, and from thesoil, in which it is combined with other elements.
1149.How do plants apply these elements to the formation of their own structures?
When those substances which form the food of plants are absorbed, either by their leaves or their roots, they are converted, with the aid of water, into anutritive sap, which answers the same purposes inplantsasblooddoes inanimals.
1150.How is the nutritive sap applied to the growth and enlargement of the plant?
Every seed contains a small amount of nutrition, sufficient for the sustentation of thegerm of the plant, until those vessels are formed, by which the nutritive elements can be absorbed and used for the further development of the living structure.
The earth, penetrated by the sun's rays, warms the sleeping germ, and quickens it into life. For a short time the germ lives uponthe seed, which, moistened and warmed by the soil, yields a kind of glutinous sap, out of which the first members of the plant are formed. And then the tender leaf, looking up to the sky, and the slender rootlet penetrating the soil, begin to draw their sustenance from the vast stores of nature.
"He causeth the grass to grow for the cattle, and herb for the service of man: that he may bring forth food out of the earth."—Psalm civ.
1151.Of what do vegetable structures consist?
Ofmembranes, or thin tissues, which, being variously arranged, form cells, tubes, air passages, &c. Offibres, which form a stronger kind of membrane, and which is variously applied to the production of the organs of the plants. And oforgans, formed by those elementary substances, by which the plants absorb, secrete, and grow, and fulfil the conditions of their existence.
1152.Why are seeds generally enveloped in hard cases?
Because the covering of the seed, like the shell of an egg, is designedto preserve the germwithin from the influence of external agencies, until the time for development has arrived, and the conditions of germination are fulfilled.
1153.Why does a seed throw out a root, before it forms a leaf?
Because moisture, which the root absorbs from the earth, is necessary to enable the germto use the nutrition which the seed itself contains, and out of which the leaf must be eliminated. Moisture forms a kind of gluten, in which the starch of the seed is dissolved, and converted into sugar, the sugar into carbonaceous sap, and the sap into cellular tissue and woody fibre, as the leaves present themselves to the influence of the air and light.
1154.Why does a plant grow?
Because, as soon as membranes and vessels are organised in the young germ, the nutritive fluid, formed by its first organs,begins to move through the fine structures, and from that time the plant commences to incorporate with its own substance the elements with which it is surrounded, that are suitable to its development.
"Can the rush grow up without mire? can the flag grow without water? Whilst it is yet in his greenness, and not cut down, it withereth before any other herb."—Job viii.
1155.Why, if we break the stem of a hyacinth, do we see a glutinous fluid exude?
Because, by breaking the stem, we rupture the vessels of the plant, and cause the nutritive fluid to escape. The sap of the plant isanalogous to the blood of man, and the vessels, to the arteries and veins of the animal body.
1156.Why, if we split the petal of a tulip, do we see cells containing matter of various colours?
Because, by splitting the petal of the flower, we disclose the anatomy of its structure, and bring to view those cells, or organs, of the vegetable body, by whichthe different colouring matters are secreted.
1157.Why, if we break a pea-shell across, do we discover a transparent membrane which may be removed from the green cells underneath?
Because we separate from the cellular, or fleshy part of the shell, the membrane,which forms the epidermis, and answers to the skin of the animal body.
1158.Why, if we cut through a cabbage stump, do we find an outer coat of woody fibre, and an inner substance of cellular matter?
Because the woody fibreforms a kind of skeleton, which supports the internal stricture of the plant, and gives form and character to its organisation. The woody fibre of plants is analogous to the bony structure of animal bodies.
1159.Why, if we cut across the stem of a plant do we see numerous tubes arranged in parallel lines?
Because we thereby bring to viewthe vessels formed by the membranes and fibresof the vegetable body, for the transmission of the fluids, by which the structure is sustained.
"It was planted in a good soil by great waters, that it might bring forth branches, and that it might bear fruit, that it might be a goodly vine."—Ezekiel xvii.
Skeleton leaves, and seed vessels of plants, form exceedingly interesting objects, and serve to illustrate the wonderful structure of plants. With patience and care, they may be produced by any person, and will afford an interesting occupation. The leaves should be gathered when they are in perfection—that is, when some of the earliest leaves begin to fall from the trees. Select perfect leaves, taking care that they are not broken, or injured by insects. Lay them in pans ofrain water, and expose them to the air to undergo decomposition. Renew the water from time to time, taking care not to damage the leaves. They need not be examined more than once a week, and then only to see that the water is sufficient to cover them. Give them sufficient time for their soft parts to become decomposed, then take them out, and laying them on a white plate with a little water, wash away carefully, with a camel-hair pencil, the green matter that clings to the fibres. The chief requirement ispatienceon the part of the operator, to allow the leaves and seed vessels sufficient time to decompose. Some leaves will take a few weeks, and others a few months, but a large panful may be put to decompose at the same time, and there will always be some ready for the process of cleansing. When they are thoroughly cleaned, they should be bleached, by steeping for a short time in a weak solution of chloride of lime. They should then be dried, and either pressed flat, or arranged in bouquets for preservation under glass shades. The result will amply reward the perseverance of the operator.
1160.Why are clayey soils unfavourable to vegetation?
Because the soil istoo close and adhesiveto allow of the free passage of air or water to the roots of the plants; it also obstructs the expansion of the fibres of the roots.
1161.Why are sandy soils unfavourable to vegetation?
Because they consist of particles that havetoo little adhesion to each other; they do not retain sufficient moisture for the nourishment of the plants; and they allow too much solar heat to pass to the roots.
1162.Why are chalk soils unfavourable to vegetation?
Because they do not absorb the solar rays,and are therefore cold to the roots of plants.
1163.Why are mixed soils favourable to vegetation?
Because they contain theelements of nutritionessential to the development of the vegetables, and the plants absorb from them those constituents which are necessary to their growth.
1164.Why do farmers sow different crops in rotation?
Because every plant takes something from the soil, and givessomething back; but all kinds of plants do not absorb nor restore the elements in the same proportions. Therefore a succession of crops of one kind would soon impoverish the soil; but a succession of crops of different kinds will compensate the soil, in some degree, for the nourishment withdrawn.
"He watereth the hills from his chambers; the earth is satisfied with the fruit of thy works."—Psalm civ.
1165.Why do farmers manure their lands?
Because, as soils vary, and crops impoverish the soils, the farmer employs manureto restore fertility, and toadapt the soils to the wants of the plantshe desires to cultivate.
It is remarkable that Nature herself points out to man the necessity for changing the succession of vegetable growths.
When plants have exhausted the soil upon which they grow, they will push their roots far in search of sustenance, and in time migrate to a new soil, while other plants will spring up and thrive upon the area vacated. When a forest in North America is destroyed by fire, the trees that grow afterwards are unlike those that the fire consumed, and evidently arise from seeds that have long lain buried in the earth, waiting the time when the ascendancy of the reigning order of plants should cease.
1166.Why are grasses so widely diffused throughout nature?
Because they form thefoodof a very large portion of the animal kingdom. They have therefore been abundantly provided. No spot of earth is allowed to remain idle long. When the foot of man ceases to tread down the path, grass immediately begins to appear; and by its universality and the hardihood of its nature, it clothes the earth as with a carpet.
Many grasses, whose leaves are so dry and withered that the plants appear dead, revive and renew their existence in the spring by pushing forth new leaves from the bosom of the former ones.—Withering's Botany.
Grasses are Nature's care. With these she clothes the earth; with these she sustains its inhabitants. Cattle feed upon their leaves; birds upon their smaller seeds; men upon the larger; for, few readers need be told that the plants which produce our bread-corn, belong to this class. In those tribes which are more generally considered as grasses, their extraordinary means and powers of preservation and increase, their hardiness, their almost unconquerable disposition to spread, their faculties of reviviscence, coincide with the intention of nature concerning them. They thrive under a treatment by which other plants are destroyed. The more their leaves are consumed, the more their roots increase. The more they are trampled upon, the thicker they grow. Many of the seemingly dry and dead leaves of grasses revive, and renew their verdure in the spring. In lofty mountains, where the summer heats are not sufficient to ripen the seeds, grasses abound which are viviparous, and consequently able to propagate themselves without seed. It is an observation, likewise, which has often been made, that herbivorous animals attach themselves to the leaves of grasses; and, if at liberty in their pastures to range and choose, leave untouched the straws which support the flowers.—Paley.
"For the earth bringeth forth fruit of herself; first the blade, then the ear, after that the full ear in the corn."—Mark v.
1167.Why do some plants droop, and turn to the earth after sunset?
Because, when the warmth of the son's rays is withdrawn, they turn downwards, andreceive the warmth of the earth by radiation.
1167.Why does the young ear of corn first appear enfolded in two green leaves?
Because the light and air wouldact too powerfully for the young ear; two leaves therefore join, and embrace the ear, and protect it until it has acquired strength, when they divide, and leave the ear to swell and ripen.
1168.Why are the seeds of plants usually formed within the corollas of flowers?
Because the petals of the flowers, surrounding the seeds,afford them protection until they are ripened, when the flower dies, and the petals fall to the ground.
1169.Why does the flower of the poppy turn down during the early formation of seed?
Because the heat would probably be too great for the seed in its early stage. The plant is therefore provided with a curiouscurve in its stalk, which turns the flower downward. But when the seeds are prepared for ripening,the stalk erects itself, and the seeds are then presented to the ripening influences of the sun.
1170.Why have plants of the pea tribe, a folding blossom called the "boat," or "keel?"
Because, within that blossom the pea is formed, and the shape of the blossom is exactly suited to that of the pea which is formed therein. The blossom is itself protected by external petals; and when the wind blows, and threatens to destroy the parts upon which the seeds depend, the plantsturn their backs to the wind, and shelter the seed.
"The fruit of the righteous is a tree of life; and he that winneth souls is wise."—Proverbs xi.
1171.Why are the leaf buds enclosed in scales which fall off as the leaf opens?
Because the scalesserve as a shelterto the tender structure of the young leaf. The scales are rudimentary leaves, formed at the end of the previous season, and which, being undeveloped then, serve to guard the young leaves of the future year.
In trees, especially those which are natives of colder climates, this point is taken up earlier. Many of these trees (observe in particular theashand thehorse-chestnut) produce the embryos of the leaves and flowers in one year, and bring them to perfection the following. There is a winter therefore to be gotten over. Now what we are to remark is, how nature has prepared for the trials and severities of that season. These tender embryos are, in the first place wrapped up with a compactness, which no art can imitate; in which state they compose what we call the bud. This is not all. The bud itself is enclosed in scales; which scales are formed from the remains of past leaves, and the rudiments of future ones. Neither is this the whole. In the coldest climates, a third preservative is added, by the bud having acoatof gum or resin, which, being congealed, resists the strongest frosts. On the approach of warm weather this gum is softened, and ceases to be an hindrance to the expansion of the leaves and flowers. All this care is part of that system of provisions which has for its object and consummation, the production and perfecting of the seeds.—Paley.
1172.Why are the seeds of many plants enclosed in a rich juice, or pulp?
Because the matter by which the seed is surrounded, as well as being intended for thenourishment and care of the seed, is designed for the use of man and of animals, by whom the seed is set free to take its place in the earth.
By virtue of this process, so necessary, but so diversified, we have the seed, at length, in stone-fruits and nuts, incased in a strong shell, the shell itself enclosed in a pulp or husk, by which the seed within is, or hath been, fed; or, more generally (as in grapes, oranges, and the numerous kinds of berries), plunged overhead in a glutinous syrup, contained within a skin or bladder; at other times (as in apples and pears) embedded in the heart of a firm fleshy substance; or (as in strawberries) pricked into the surface of a soft pulp.
These and many more varieties exist in what we callfruits. In pulse, and grain, and grasses; seeds (as in the pea tribe) regularly disposed in parchment pods, which, though soft and membranous, completely exclude the wet even in the heaviest rains; the pod also, not seldom, (as in the bean), lined with a fine down; at other times (as in the senna) distended like a blown bladder; or we have the seed enveloped in wool (as in the cotton-plant), lodged (as in pines) between the hard and compact scales of a cone, or barricadoed (as in the artichoke and thistle) with spikes and prickles; in mushrooms, placed under a pent-house; in ferns, within slits in the back part of the leaf; or (which is themost general organisation of all) we find them covered by strong, close tunicles, and attached to the stem according to an order appropriated to each plant, as is seen in the several kinds of grains and of grasses.
"And I will send grass in thy fields for thy cattle, that thou mayest eat, and be full."—Deuteronomy xi.
In which enumeration, what we have first to notice is, unity of purpose under variety of expedients. Nothing can be moresinglethan the design; morediversifiedthan the means. Pellicles, shells, pulps, pods, husks, skin, scales armed with thorns, are all employed in prosecuting the same intention. Secondly; we may observe, that in all these cases, the purpose is fulfilled within a just andlimiteddegree. We can perceive, that if the seeds of plants were more strongly guarded than they are, their greater security would interfere with other uses. Many species of animals would suffer, and many perish, if they could not obtain access to them. The plant would overrun the soil; or the seed be wasted for want of room to sow itself. It is, sometimes, as necessary to destroy particular species of plants, as it is, at other times, to encourage their growth. Here, as in many cases, a balance is to be maintained between opposite uses. The provisions for the presentation of seeds appear to be directed, chiefly against the inconstancy of the elements, or the sweeping destruction of inclement seasons. The depredation of animals, and the injuries of accidental violence, are allowed for in the abundance of the increase. The result is, that out of the many thousand different plants which cover the earth, not a single species, perhaps, has been lost since the creation.
When nature has perfected her seeds, her next care is to disperse them. The seed cannot answer its purpose, while it remains confined in the capsule. After the seeds therefore are ripened, the pericarpium opens to let them out, and the opening is not like an accidental bursting, but for the most part, is according to a certain rule in each plant. What I have always thought very extraordinary; nuts and shells, which we can hardly crack with our teeth, divide and make way for the little tender sprout which proceeds from the kernel. Handling the nut, I could hardly conceive how the plantule was ever to get out of it. There are cases, it is said, in which the seed-vessel, by an elastic jerk, at the moment of its explosion, casts the seeds to a distance. We all, however, know, that many seeds (those of most composite flowers, as of the thistle, dandelion, &c.) are endowed with what are not improperly calledwings; that is, downy appendages, by which they are enabled to float in the air, and are carried oftentimes by the wind to great distances from the plant which produces them. It is the swelling also of this downy tuft within the seed-vessel that seems to overcome the resistance of its coats, and to open a passage for the seed to escape.
But theconstitutionof seeds is still more admirable than either their preservation or their dispersion. In the body of the seed of every species of plant, or nearly of every one, provision is made for two grand purposes: first, for the safety of thegerm; secondly, for the temporary support of the future plant. The sprout, as folded up in the seed, is delicate and brittle beyond any other substance. It cannot be touched without being broken.
Yet in beans, peas, grass-seeds, grain, fruits, it is so fenced on all sides, so shut up and protected, that whilst the seed itself is rudely handled, tossed into sacks, shovelled into heaps, the sacred particle, the miniature plant remains unhurt. It is wonderful, also, how long many kinds of seeds, by the help of their integuments, and perhaps of their oils, stand out against decay. A grain of mustard-seed has been known to lie in the earth for a hundredyears; and as soon as it had acquired a favourable situation, to shoot as vigorously as if just gathered from the plant. Then, as to the second point, the temporary support of the future plant, the matter stands thus. In grain, and pulse, and kernels, and pipins, the germ composes a very small part of the seed. The rest consists of a nutritious substance, from which the sprout draws its aliment for some considerable time after it is put forth; viz., until the fibres, shot out from the other end of the seed, are able to imbibe juices from the earth, in a sufficient quantity for its demand. It is owing to this constitution that we see seeds sprout, and the sprouts make a considerable progress, without any earth at all.
"Say not ye, There are four months, and then cometh harvest? behold, I say unto you, Lift up your eyes, and look on the fields; for they are white already to harvest."—John iv.
From the conformation of fruits alone, one might be led, even without experience, to suppose, that part of this provision was destined for the utilities of animals. As limited to the plant, the provision itself seems to go beyond its object. The flesh of an apple, the pulp of an orange, the meat of a plum, the fatness of the olive, appear to bemorethan sufficient for the nourishing of the seed or kernel. The event shows, that this redundancy, if it be one, ministers to the support and gratification of animal natures; and when we observe a provision to be more than sufficient for one purpose, yet wanted for another purpose, it is not unfair to conclude that both purposes were contemplated together.—Paley.
1173.Why have climbing plants tough curly tendrils?
Because,having no woody stalks of their ownto support them, they require to take hold of surrounding objects, and raise themselves from the ground by climbing. Their spiral tendrils are, therefore, so many hands, assisting them to rise from the earth.
1174.Why does the pea put forth tendrils, and the bean not?
Because the bean has in its stalksufficient woody fibre to support itself, but the pea has not. We do not know a single tree or shrub having a firm strong stem sufficient for its support which isalsosupplied with tendrils.
1175.Why do the ears of wheat stand up by day, and turn down by night?
Because, when the ear is becoming ripe, the cold dew falling into the ear, mightinduce blight; the ears therefore turn down to the earth, andreceive warmth by radiation.
1176.Why have grasses, corn, canes, &c., joints, or knots in their stalks?
Because a long hollow stem would be liable to bend and break. But the joints are so many points where the fibres are bound together, and the structuregreatly strengthened.
"Then shall the earth yield her increase; and God, even our own God, shall bless us."—Psalm xlvii.
1177.Why have the berries of the mistletoe a thick viscid juice?
Because the mistletoe is aparasiticalplant, growing upon the bark of other trees. It will not grow in the ground; its seeds are therefore filled with an exceedingly sticky substance, which serves to attach them to the bark of trees, to which the berries attach themselves at once, by throwing out tough fibres; and the next year the plant grows.
Fig. 75.—THE MISTLETOE.
Fig. 75.—THE MISTLETOE.
1178.How are the seeds of the mistletoe transferred from its own stem to the bark of trees?
Various birds, and particularly themissel thrush, feed upon the berries. As the bird moves in pursuit of its food, the viscid berries attach themselves to its feathers, and in this way the thrush is the instrument which conveys the seed to the spot to which it adheres, and from which the tree ultimately grows.
1179.What is the circulation of the sap in plants?
The circulation of the sap is the movement of the nutritive juices by which the plant is sustained. There is a slow uninterruptedmovement of the sap from the root through the stems to the leaves, and downwards from the leaves through the bark to the root.
"For the sun is no sooner arisen with a burning heat, but it withereth the grass, and the flower thereof falleth, and the grace of the fashion of it perisheth: so also shall the rich man fade away in his ways."—James i.
1180.Why does the sap of plants thus ascend and descend?
Because itconveys upwardfrom the ground some of the matter by which the plant is to be nourished, and which must undergo digestion in the leaves; and itbrings downwardfrom the leaves the matters absorbed, for the nourishment of the plant, and discharges through the root the substances which the plant cannot use.
The movement of the sap is most active in the spring; but in the depths of the winter it almost ceases.
There are other motions of the sap in plants, which are calledspecial, in distinction from the ascending and descending of the sap, which is calledgeneral, or common to all plants. The special movements of the sap are peculiar to certain plants, in some of which a fluid, full of little green cells, is found to have a rotatory motion; in other plants, a milky fluid is found to move through particular tissues of the vegetable structure.
1181.Why are the leaves of plants green?
Because they secrete a carbonaceous matter, namedchlorophyll, from which they derive their green colour.
1182.Why are the hearts of cabbages, lettuces, &c., of a pale yellow colour?
Because the action oflightis necessary to the formation ofchlorophyll; and as the leaves are folded upon each other, they exclude the light, and the green matter is not formed.
1183.Why do leaves turn brown in the autumn?
Because, when their power of decomposing the air declines, theoxygenabsorbed in the carbonic acid gas,lodges in the leaf, imparting to it a red or brown colour.
1184.Why do succulent fruits, such as gooseberries, plums, &c., taste acid?
Because, in the formation of juices, a considerable amount ofoxygenis absorbed, and the oxygen imparts acidity to the taste.
"The earth is full of the goodness of the Lord."—Psalm xxxiii.
1185.Why do ripe fruits taste sweet, and unripe fruits taste sour?
Because the juices of the ripe fruit contain a large proportion ofsugar, which in the unripe fruit has not been formed.
1186.Why do some leaves turn yellow?
Because they retain an excess ofnitrogen. Leaves undergoing decay turn either yellow, red, crimson, or violet. Yellow is due to the excess ofnitrogen; red and crimson to various proportions ofoxygen; violet to a mixture ofcarbon; and green tochlorophyll.
1187.Why do leaves fall off in the autumn?
Because they have supplied for a season the natural wants of the tree. Every part has received nutrition through the spring and summer months; and the wants of the tree being supplied, the chief use of the leaf ceases, and it falls to the ground to decay, and enrich the soil.
1188.Why do plants suffer from the smoke of cities?
Because the smokeinjures the porous structure of the leaves, and interferes with their free respiration.
1189.Why are vegetable productions so widely diffused?
Because they everywhere form thefood of the animal creation. Without them, neither man nor beast could exist. Even the flesh-eating animals are sustained by them, since they live by preying upon the bodies of vegetable-eaters.
They also enrich and beautify the earth. They present the most charming diversities of proportions and features. From the cowslip, the primrose, and the blue-bell of our childish days, to the broad oak under which we recline, while children gambol round us, they are all beautiful or sublime, and eminently useful in countless ways to man.
They spread a carpet over the surface of the earth; they cling to old ruins, and cover hard rocks, as though they would hide decay, andgive warmth to the coldness of stone. In tropical climates they supply rich fruits full of cool and refreshing juices, and they spread out upon the crests of tall trees those broad leaves which shelter the native from the scorching heat of the sun.
They supply our dwellings with furniture of every kind, from the plain deal table, to the handsome cabinet of satin or rose-wood; they afford rich perfumes to the toilette, and luscious fruits and wines to the desert; they charm the eye of the child in the daisied field; they adorn the brow of the bride; they are laid in the coffin with the dead; and, as the cypress or the willow bend over our graves, they become the emblems of our grief.
"The glory of the Lord shall endure for ever: the Lord shall rejoice in his works."—Psalm civ.
1190.What is mahogany?
Mahogany is the wood of trees brought chiefly from South America and Spain. The finest kind is imported from St. Domingo, and an inferior kind from Honduras.
We all know the beauty of mahogany wood. But we do not all know that mahogany was first employed in the repair of some of Sir Walter Raleigh's ships at Trinidad in 1597. The discovery of the beauty of its grain for furniture and cabinet work was accidental. Dr. Gibbons, a physician of eminence, was building a house in King-street, Covent-garden; his brother, captain of a West Indiaman, had brought over some planks of mahogany as ballast, and he thought that the wood might be used up in his brother's building, but the carpenters found the wood too hard for their tools, and objected to use it. Mrs. Gibbons shortly afterwards wanted a small box made, so the doctor called upon his cabinet-maker, and ordered him to make a box out of some wood that lay in his garden. The cabinet-maker also complained that the wood was too hard. But the doctor insisted upon its being used, as he wished to preserve it as a memento of his brother. When the box was completed, its fine colour and polish attracted much attention; and he, therefore, ordered a bureau to be made of it. This was done, and it presented so fine an appearance that the cabinet-maker invited numerous persons to see it, before it was sent home. Among the visitors was her Grace the Duchess of Buckingham, who immediately begged some of the wood from Mr. Gibbons, and employed the cabinet-maker to make her a bureau also. Mahogany from this time became a fashionable wood, and the cabinet-maker, who at first objected to use it, made a great success by its introduction.
1191.What is rose-wood?
Rosewood is the wood of a tree which grows in Brazil. It is, generally speaking, too dark for large articles of furniture, but is admirably adapted for smaller ones. It is expensive, and the hardness of the wood renders the cost of making articles of it very high.
"I am come up to the height of the mountains, to the sides of Lebanon, and will cut down the tall cedars thereof, and the choice fir trees thereof."—II. Kings xxiii.
Respecting the other woods used in the manufacture of furniture, we have nothing special to say, except of the oak—the emblem of our native land. This tree yields a most useful and durable wood, and as it not only defends our country by supplying our "wooden walls," but gives to us the floors of our houses, furnishes our good substantial tables, and comfortable arm-chairs, it will be well for us to know a few facts about this celebrated tree. It is said that there are no less than one hundred and fifty species of the oak. The importance of the growth of oaks may be gathered from the fact, that the building of a 70-gun ship would take forty acres of timber. The building of a 70-gun ship is estimated to cost about £70,000. Oak trees attain to the age of 1,000 years. The oak enlarges its circumference from 10½ inches to 12 inches in a year. The interior of a great oak at Allonville, in Normandy, has been converted into a place of worship. An oak at Kiddington, served as a village prison. A large oak at Salcey, was used as a cattle fold; and others have served as tanks, tombs, prisons, and dwelling-houses.
TheMammoth tree, which is exhibiting at the Crystal Palace, is one of the great wonders of the vegetable creation. It is the grand monarch of the Californian forest, inhabiting a solitary district on the elevated slopes of the Sierra Nevada, at 5,000 feet above the sea-level. From 80 to 90 trees exist, all within the circuit of a mile, and these varying from 250 to 320 feet in height, and from 10 to 20 feet in diameter. The bark is from 12 to 15 inches in thickness; the branchlets are somewhat pendent, and resemble those of cypress or juniper, and it has the cones of a pine. Of a tree felled in 1853, 21 feet of the bark from the lower part of the trunk were put in the natural form as a room, which would contain a piano, with seats for forty persons; and on one occasion 150 children were admitted. The tree is reputed to have been above 3,000 years old; that is to say, it must have been a little plant when Samson was slaying the Philistines. The portion of the tree exhibiting at the palace is 103 feet in height, and 32 feet in diameter at the base.
1192.What is tea?
Tea is the leaf of a shrub (Thea Chinensis). The plant usually grows to the height of from three to six feet, and resembles in appearance the well-known myrtle. It bears a blossom not unlike that of the common dog-rose. The climate most congenial to it is that between the 25th and 33rd degrees of latitude. The growth of good tea prevails chiefly in China, and is confined to a few provinces. Thegreenandblackteas are mere varieties, depending upon the culture, time of gathering, mode of drying, &c.Coffee was used in this country before tea.in 1664, it is recorded, the East India Company bought 2lb. 2oz. of coffee as a present for the king. In the year 1832, there were 101,687 licensed tea dealers in the United Kingdom. Green tea was first used in 1715. A dispute with America about the duty upon tea led to the American war, out of which arose American independence. The consumption of teathroughout the whole world is estimated at above 52,000,000 lbs., of which the consumption of Great Britain alone amounts to 30,000,000. (See1225).
"Every man should eat and drink, and enjoy the good of all his labour, it is the gift of God."—Ecclesiastes iii.
1193.What is coffee?
Coffee is the berry of the coffee plant, which was a native of that part of Arabia called Yemen, but it is now extensively cultivated in India, Java, the West Indies, Brazil, &c. (See1224).
The first coffee-house in London was opened in 1652, under the following circumstances. A Turkey merchant named Edwards, having brought along with him from the Levant, some bags of coffee, and a Greek servant who was skilful in making it, his house was thronged with visitors to see and taste this new beverage. Being desirous to gratify his friends without putting himself to inconvenience, he allowed his servant to open a coffee-house, and to sell coffee publicly.
Here we have another illustration of the great results springing from trifling causes. Coffee soon became so extensively used that taxes were imposed upon it. In 1660 a duty of 4d. a gallon was imposed upon all coffee made and sold. Before 1732 the duty upon coffee was 2s. a pound; it was afterwards reduced to 1s. 6d., at which it yielded to the revenue, for many years, £10,000 per annum. The duty has been gradually reduced, and the consumption has gone on increasing, until at last above 25,000,000 of pounds are consumed annually! Fancy this great result springing from a "friendly coffee party" that assembled in the year 1652.
1194.What is chocolate?
It is a cake prepared from the cocoa-nut. The nut is first roasted like coffee, then it is reduced to powder and mixed with water, the paste is then put into moulds and hardened. The properties are very healthful, but its consumption is very insignificant, as compared with tea or coffee. The cocoa tree grows chiefly in the West Indies and South America.
1195.What is cocoa?
Cocoa is also a preparation from the seeds or beans of the cocoa tree. But the best form of cocoa for family use is to obtain the beans pure, as they are now commonly sold ready for use, and to break them and then grind them in a large coffee mill.
1196.What is chicory?
Chicory is the root of the common endive, dried and roasted as coffee, for which it is used as a substitute. Some persons prefer the flavour of chicory admixed with coffee. But very oppositeopinions prevail respecting the qualities of chicory. We believe it to be perfectly healthful, and attribute the prejudice that prevails against it, to its having been used, from its cheapness, to adulterate coffee.
"He that tilleth the land shall have plenty of bread: but he that followeth after vain persons shall have poverty enough."—Proverbs xxviii.
1197.What is sugar?
Sugar is a sweet granulated substance, which may be derived from many vegetable substances, but the chief source of which is the sugar cane. The other chief sources that supply it are the maple, beet-root, birch, parsnip, &c. It is extensively used all over the world. Sugar is supposed to have been known to the ancient Jews. It was found in the East Indies by Newcheus, Admiral of Alexander, 325 B.C. It was brought into Europe from Asia.
The art of sugar refining was first practised in England, in 1659, and sugar was first taxed by name by James II., 1685. Sugar is derived from the West Indies, Brazil, Surinam, Java, Mauritius, Bengal, Siam, the Isle de Bourbon, &c. &c. Before the introduction of sugar to this country, honey was the chief substance employed in making sweet dishes; and long after the introduction of sugar it was used only in the houses of the rich. The consumption in England in 1700 reached only 10,000 tons; in 1834 it had reached 180,000 tons. The English took possession of the West Indies in 1672, and in 1646 began to export sugar. In 1676 it is recorded that 400 vessels, averaging 150 tons, were employed in the sugar trade of Barbadoes. Jamaica was discovered by Columbus, and was occupied by the Spaniards, from whom it was taken by Cromwell, in 1656, and has since continued in our own possession. When it was conquered there were only three sugar plantations upon it. But they rapidly increased. Until the abolition of slavery in the West Indies, the production of sugar was almost exclusively limited to slave labour. (See1226).
1198.What is wheat?
Wheat, rye, barley, oats, millet, and maize, all belong to the natural order of grain-bearing plants. They all grow in a similar manner, and all yield starch, gluten, and a certain amount of phosphates. They are commonly spoken of asfarinaceous foods.
"I clothed thee also with broidered work, and shod thee with badgers' skin, and I girded thee about with fine linen, and I covered thee with silk."—Ezekiel xvi.
From the Sacred writings we learn that unleavened bread was common in the days of Abraham. In the earlier periods of our own history, people had no other method of making bread than by roasting corn, and beating it in mortars, then wetting it into a kind of coarse cake. In 1596, rye bread and oatmeal formed a considerable part of the diet of servants, even in great families. In the time of Charles the First, barley bread was the chief food of the people. In many parts of England it was more the custom to make bread at home than at present. In 1804, there was not a single public baker in Manchester. In France, when the use of yeast was first introduced, it was deemed by the faculty of medicine to be so injurious to health that its use was prohibited under the severest penalties.Herault says that, during the siege of Paris by Henry the Fourth, a famine raged, and bread sold at a crown a pound. When this was consumed, the dried bones from the charnel house of the Holy Innocents were exhumed, and a kind of bread made therefrom. Bread-street, in London, was once a bread market. From the year 1266, it had been customary to regulate by law the price of bread in proportion to the price of wheat or flour at the time. This was called the assize of bread; but, in 1815, it was abolished. In the year 272 there was a famine in Britain so severe that people ate the bark of trees; forty thousand persons perished by famine in England in 310! In the year 450 there was a famine in Italy so dreadful that people ate their own children. A famine, commencing in England, Wales, and Scotland, in 954, lasted four years. A famine in England and France, in 1193, led to a pestilential fever, which lasted until 1195. In 1315 there was again a dreadful famine in England, during which people devoured the flesh of horses, dogs, cats, and vermin! In the year 1775, 16,000 people died of famine in the Cape de Verds. These are only a few of the remarkable famines that have occurred in the course of history. Let us thank God that we live in times of abundance, when improved cultivation, the pursuit of industry, and the settlement of the laws, render such a calamity as a famine almost an impossibility.
1199.What is cotton?
Cotton is a species of vegetable wool, produced by the cotton shrub, called, botanically,Gossypium herbaceum, of which there are numerous varieties. It grows naturally in Asia, Africa, and America, and is cultivated largely for purposes of commerce.
The precise time when the cotton manufacture was introduced into England is unknown; but probably it was not before the 17th century. Since then, what wonderful advances have been made! The cotton trade and manufacture have become a vast source of British industry, and of commerce between nations. It was some years ago calculated that the cotton manufacture yielded to Great Britain one thousand millions sterling. The names of Hargreaves, Arkwright, Crompton, Cartwright, and others, have become immortalised by their inventions for the improvement of the manufacture of cotton fabrics. Little more than half a century has passed since the British cotton manufactory was in its infancy—now it engages many millions of capital—keeps millions of work people employed; freights thousands of ships that are ever crossing and re-crossing the seas; and binds nations together in ties of mutual interest. The present yearly value of cotton manufactures in Great Britain is estimated at £34,000,000. About £6,044,000 of the above sum is distributed yearly among working people as wages.
1200.What is silk?
Silk, though not directly a vegetable product, is, nevertheless, indirectly derived from the vegetable creation, since it is a thread spun by the silk-worm from matter which the worm derives from themulberry leaf.
"And there was a man in Maon, whose possessions were in Carmel; and the man was very great, and he had three thousand sheep, and a thousand goats: and he was shearing his sheep in Carmel."—I Samuel xxv.
Silk is supplied by various parts of the world, including China, the EastIndies, Turkey, &c., where the silk-worm has been found to thrive. The attempts that have been hitherto made to cultivate it in this country have proved unsuccessful. At Rome, in the time of Tiberius, a law passed the senate which, as well as prohibiting the wearing of massive gold jewels, also forbade the men to debase themselves by wearing silk. There was a time when silk was of the same value as gold—weight for weight—and it was thought to grow upon trees. It is recorded that silk mantles were worn by some noble ladies at a ball at Kenilworth Castle, 1286. It was first manufactured in England in 1604. In the reign of Elizabeth, the manufacture of silk in England made rapid strides. In 1666, there were 40,000 persons engaged in the silk trade. The silk throwsters of the metropolis were enrolled in a fellowship in 1562, and were incorporated in 1629. In 1685, a considerable impetus was given to the English silk manufactures. Louis the Fourteenth of France revoked the edict of Nantes. The edict of Nantes was promulgated by Henry the Fourth of France in 1598. It gave to the Protestants of France the free exercise of their religion. Louis the Fourteenth revoked this edict in 1685, and thereby drove the Protestants as refugees to England, Holland, and parts of Germany, where they established various manufactures. Many of these French refugees settled in Spitalfields, and there founded extensive manufactories, which soon rivalled those of their own country; and thus the intolerance of the king was justly punished. What important facts we see connected with the simple thread of the silk-worm!
1201.What is wool?
Wool is a kind of soft hair or coarse down, produced by various animals, but chiefly by sheep.
This is another of the useful productions of nature, for which we are indirectly indebted to the vegetable kingdom; for were it not for the rich pastures forming the green carpet of the earth, it would be impossible for man to keep large flocks of sheep for the production of wool. Wool, like the hair of most animals, completes its growth in a year, and then exhibits a tendency to fall off. For the production of wool in England and Wales it has been estimated that there are no less than 27,000,000 sheep and lambs; and, in Great Britain and Ireland, the total number is estimated at 82,000,000. Wool was not manufactured in any quantity in England until 1331, when the weaving of it was introduced by John Kempe and other artizans from Flanders. The exportation or non-exportation of wool has from time to time formed a vexed subject for legislators. Woollen clothes were made an article of commerce in the reign of Julius Cæsar. They were made in England prior to 1200. Blankets were first made in England in 1340. The art of dyeing wools was first introduced into England in 1608. The annual value of the raw material in wool is set down at £6,000,000; the wages of workmen engaged in the wool trade, £9,600,000. The number of people employed is said to be 500,000.
1202.What is starch?
Starch is one of the most useful products of the vegetable kingdom. As a rule,a vegetable, if nutritious at all, is soaccording to the amount of starch which it contains. It is most abundantly found in the seeds of plants, and especially in thewheattribe.
It is also met with in the cellular tissues of plants, and especially in such underground stems as thepotatoe,carrot,turnip,&c., and the stems of thesago-palmfig, &c. It is also found in thebarkof some trees.
"Every good gift and every perfect gift is from above, and cometh down from the Father of lights, with whom is no variableness, neither shadow of turning."—James i.
1203.Why is the horse chestnut, though containing a great quantity of starch, unfit for food?
Because (like many other vegetable productions) it contains with the starch anacrid juice, which renders it unhealthy; and although the juice can be separated from the starch, the process is too expensive to be made generally available.
The starch which is used for domestic purposes is an artificial preparation, and does not properly represent the starch of nutrition. A better idea of it is afforded bythe meal of a flowery potatoe. The starch used by laundresses is frequently prepared from diseased potatoes. This does not impair the quality of the starch, for the purposes of the laundress, and the reason why potatoes that are diseased are thus applied is, that it is one method of saving some part of their value. The finest kinds of starch are prepared from rice. It is prepared by breaking the pulp, and disengaging the starch from the cells; and it is then put through other processes to remove the fragments of the broken cells. But in the flowery meal of the potatoe, the starch cell may be seen entire.