of tissue forms the great bulk of the stems of plants, and constitutes the wood or timber which they afford. In such plants as the flax, hemp, and cocoa-nut, these tubes are so loosely held together that they may be separated, and are then used for weaving the various kinds of linen, hempen-cloth, and cocoa-nut fibre fabrics. They are also formed into string and ropes.

3

Fig. 9,

15. The vessels which contain spiral fibres, or portions of them, present a great variety of appearances (fig. 2), and have obtained the names of ducts, dotted ducts, porous vessels, spiral vessels, trachea, and glandular woody tissue.

16. One set of vessels are branched, and in plants with milky juices are easily seen to convey a current of sap. They have been supposed to form an important system in but their true nature and They are called laticiferous

the structure of the plant,
functions are still doubtful.
tissue, or vessels of the latex (fig. 9).

EDWIN LANKESTER.

HYMN ON THE SEASONS.

THESE, as they change, Almighty Father, these
Are but the varied God. The rolling year
Is full of thee. Forth in the pleasing Spring
Thy beauty walks, thy tenderness and love.
Wide flush the fields; the softening air is balm ;
Echo the mountains round; the forest smiles,
And every sense and every heart is joy.
Then comes thy glory in the Summer months,
With light and heat refulgent. Then thy sun
Shoots full perfection through the swelling year:
And oft thy voice in dreadful thunder speaks,

And oft at dawn, deep noon, or falling eve,
By brooks and groves, in hollow-whispering gales
Thy bounty shines in Autumn unconfined,
And spreads a common feast for all that lives.
In Winter awful thou! with clouds and storms
Around thee thrown, tempest o'er tempest rolled.
Majestic darkness! on the whirlwind's wing,
Riding sublime, thou bid'st the world adore,
And humblest nature with thy northern blast.
Mysterious round! what skill, what force divine,
Deep-felt in these appear! a simple train,
Yet so delightful mixed, with such kind art,
Such beauty and beneficence combined;
Shade, unperceived, so softening into shade;
And all so forming an harmonious whole,
That, as they still succeed, they ravish still.
But wandering oft, with rude unconscious gaze,
Man marks not thee, marks not the mighty hand
That, ever busy, wheels the silent spheres ;
Works in the secret deep; shoots, steaming, thence
The fair profusion that o'erspreads the spring:
Flings from the sun direct the flaming day;
Feeds every creature, hurls the tempest forth,
And, as on earth this grateful change revolves,
With transport touches all the springs of life.

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Should fate command me to the farthest verge Of the green earth, to distant barbarous climes, Rivers unknown to song; where first the sun Gilds Indian mountains, or his setting beam Flames on the Atlantic isles; 'tis nought to me; Since God is ever present, ever felt,

In the void waste as in the city full;

And where He vital breathes, there must be joy.
When even at last the solemn hour shall come,
And wing my mystic flight to future worlds,
I cheerful will obey; there with new powers,
Will rising wonders sing. I cannot go
Where universal love not smiles around,
Sustaining all yon orbs, and all their suns;
From seeming evil still educing good,
And better thence again, and better still,
In infinite progression.

THOMSON.

"His going forth is from the end of the heaven, and his circuit unto the ends of it: and there is nothing hid from the heat thereof."

1. WARMTH IS ESSENTIAL TO LIFE.-As travellers go into the colder regions of the earth, they find fewer and fewer living creatures, until, at length, in the frozen waters that surround the pole, scarcely a plant, or an animal is to be seen during the greater part of the dreary year.

The warmth on the earth's surface is mainly dependent upon the influence of the sun. Sunshine falls on the ground, and the ground grows warm under its presence, exactly as a book, or a piece of wood does, when placed in front of a burning fire. But the amount of heat the terrestrial surface acquires, is in proportion to the directness with which the sun's rays strike on the ground, and to the length of time they continue to do so without interruption. Hence, the earth's surface gets hotter and hotter, during a summer's day, and then colder and colder during the ensuing night. In India the sun sometimes heats the earth's surface so much, that it is half-way between the temperature of freezing and boiling water. The wooden furniture of houses then warps and shrinks, as it would if placed in an oven. Glass has been known to crack. Under such circumstances, people are compelled to lie in the shade, and do nothing during the middle of the day. The slightest exertion seems to be too much for their oppressed frames. Excessive heat is as unsuitable to the offices of life, as warmth is essential for their healthy performance.

2. The degree of heat, that people find it most pleasant to live in, is that which is experienced in the shade, during most English summer-days. Men of science,

in order that they may have a measure of temperature, divide the difference of warmth that separates freezing from boiling water into one hundred and eighty equal parts, and then term each of these parts a degree of heat. They thus say that boiling water is one hundred and eighty degrees hotter than ice. Now the agreeable warmth of the English summer-days is thirty of these same heat degrees hotter than freezing water. This is denominated, in the language of science, a temperature of sixty-two degrees, for the heat-reckoning is made to begin thirty-two degrees below the freezing point. In such a temperature men can sit still with very little clothing on them, and yet do not feel cold. When the air is colder than sixty-two degrees, they are mostly driven, by their feelings, to adopt some artificial plan to increase the warmth of their frames.

Over the greater part of the earth's surface, the heat is commonly less than this agreeable temperature of sixty-two degrees. In England it only reaches such a height, in the day-time, during four months of the year. Consequently, men are driven to adopt various devices for keeping themselves sufficiently warm. Of all these devices, the most common and the most successful one is the burning of artificial fires. They set light to fuel placed in iron grates, and then husband the heat which is produced during the burning of the fuel, by confining it in closed rooms as long as they can. In this way they make the air of these closed rooms take up the heat set free from the fuel, and then live in the heated air.

3. All kinds of fuel, which are capable of giving off heat when burned, contain more or less of two distinct principles; of these principles, one is the solid, black substance, known as carbon; the other is the light, inflammable gas, called hydrogen, which is the same that is employed in inflating balloons. Coal consists alinost entirely of these two bodies, mingled together. The carbon constitutes its dense, black mass: the hydrogen is the light vapour that escapes from it, when it is greatly heated, and bursts into flame. When coal is burned, it slowly wastes away, and gradually disappears

from sight. The reason for this is, that it is surrounded by a strong, although invisible agent, which is able to seize upon it piecemeal, and carry it away. This invisible and strong agent, that surrounds the coal, floats in the air; it is indeed itself a part of the air. It is called oxygen gas.

4. Now the little imperceptible atoms of which oxygen gas is composed, possess a peculiar affection for the analogous atoms, both of dense, solid carbon, and of light, gaseous hydrogen. This affection is held in control and rendered inoperative, so long as the carbon and the hydrogen are cold.

When these are considercomes into active play.

ably heated, however, it Oxygen-atoms then seize on carbon-atoms and float off with them, in intimate combination with themselves, the two assuming the air-like gaseous state, and becoming what is known as carbonic acid. Oxygen-atoms also seize on hydrogen-atoms and float away with them, the two being transmuted by the union into watery vapour. The carbonic-acid and watery vapour, formed when coal is burned in the presence of oxygen, are carried, with the stream of heated air, up the chimney, and are scattered, in the condition of thin, invisible vapour, abroad upon the wind. Such is the wonderful process that takes place whenever a combustible substance is burned-dense, visible matter is changed into light invisible vapour, or air, and the change is brought about by the combined influence of two things-the presence of great heat, to give a start to the transformation, and the presence, of corrosive oxygen, the chemically-powerful portion of the atmosphere, to keep up the process of transformation when once set going. Every one knows how the corrosive property of the air eats into bright iron, and wastes it away in rust. The same property eats into combustible coal when made red-hot, and wastes it away in vapour, which floats off into the air, instead of adhering all over its surface, as a coat of rust.

5. The animal body requires a temperature that is considerably higher than sixty-two degrees, in order that the blood may circulate freely, and all the several