Page images
PDF
EPUB

quisite workmanship, which were executed | at that time, entirely by his hands.

The shop of Watt became, too, a sort of academy, where all the learned in Glasgow resorted to discuss points of literature and science. Whenever any puzzle came in their way, they went to this young mechanician, knowing that every thing to which his attention was directed, was the beginning of a new and serious study, and that he would not quit it until he had turned it to some account. On one occasion the solution of a problem seemed to require the perusal of a work of Leupold's, and he forthwith learned German. At another time, and for a similar reason, he made himself master of Italian. Yet with an extraordinary acquaintance with mathematical and mechanical philosophy, and an aptitude and disposition for making constant attainments, there was nothing of that pride and ostentation which so greatly detract from the influence of some men, but a simplicity, candour, and generosity of spirit, which awakened the strong and cordial attachment of his numerous acquaintances. It is worthy of remark, that his various studies were pursued in the night, and never interfered with the proper labours of the day. He seemed to find pleasure not only in almost unceasing labours, but in the most difficult undertakings, and those for which he might have been considered the least adapted. As a proof of this, it may be stated, that though he was utterly insensible to the charms of music, and never learned to distinguish a single note from another, he undertook to build an organ. Even here he was also successful. "The new instrument, says his biographer, "displayed the most important improvements in its mechanical parts, in the stops, in the indications and regulations of the strength of the blast; but you will be astonished to learn, that its harmonic qualities were not less remarkable, and delighted the best performers. Watt solved an important part of the problem; he found out the temperament assigned by a master of the art, by help of the phenomena of the beats of imperfect consonances, then very ill understood, and of which he could have gained no knowledge, except from the profound but very obscure work of Dr. Robert Smith of Cambridge."

[ocr errors]

At the period in which those labours were pursued, the steam engine was a rude machine, the result of simple experiments on the compression of the at

mosphere, and the condensation of steam. On his exertions for its improvement, it would be interesting to enlarge; but a brief notice is all that is now practicable. The chief result was the condensation of the steam in a vessel detached from the cylinder in which the piston works, by which incalculable advantages were secured. After overcoming much opposition from interest and prejudice, he constructed an engine, and used it with complete success at Carron, with the founder of which, Dr. Roebuck, he entered into partnership. On some reverse, leading to temporary embarrassment, Watt gave up his invention, for which he had taken out a patent, changed his course, and was employed for the next eight years, in trigonometrical surveys and operations in Scotland. In 1774, he became connected with Mr. Boulton of Soho, near Birmingham, which led to the two friends petitioning parliament for an extension of the patent for the steam engine, it having now only a few years to run, and after violent opposition, they gained their object. Steam engines now came into use in all the mining districts, and Boulton and Watt received, as their remuneration, the third part of the fuel which was saved by each of their machines.

It appears, however, that the Cornish miners discovered increased reluctance from year to year in paying the rent due for their engines, and availed themselves of the first difficulties occasioned by pirates of the invention, to pretend that they were free from all obligations. A long and costly litigation was the consequence; but in the end, Boulton and Watt were successful. Happily, the annoyance and irritation experienced by the latter, did not impede his efforts for the improvement of his engines, and the enlargement of their power. The pumps, which were at first merely instruments of exhaustion, he changed into agents of great power and utility. Regularity of action was also attained, so that the steam engine is equally successful in embroidering muslins, or forging anchors; in weaving the most delicate fabrics, or giving rapid motion to ponderous machinery. A further discovery was that of the expansion of steam; so that in the steam engines of Cornwall, one bushel of coal did the work of twenty men, for nearly ten hours, and at the cost in those districts of only nine-pence.

Sir John Herschel has strikingly illustrated the importance of this invention by the following comparisons:

the steam engine, enlarged the resources of his country, increased the power of man, and rose to an eminent place among the most illustrious followers of science, and the real benefactors of the world."

"The ascent of Mont Blanc, from the | Watt; who directing the force of an orivalley of Chamouni, is considered, and ginal genius, early exercised in philosojustly so, as the most toilsome undertak-phical research, to the improvement of ing that a man can perform in two days. Thus the maximum of mechanical exertion, which we are capable of making in twice twenty-four hours, is measured by the raising the weight of our body to the height of Mont Blanc. This exertion, or its equivalent, a steam engine will make by consuming two pounds of coal! Watt has then made it appear, that the strength which a man working for a day can exert, is no more than is contained in a pound of coal. Herodotus relates, that the construction of the great pyramid of Egypt occupied a hundred thousand men for twenty years. The pyramid is built of calcareous stone; its cubic contents can be easily calculated; and hence the conclusion is drawn, that its weight is about thirteen millions of millions of pounds. To raise this weight to the height of a hundred and twenty-five feet, the height of the centre of gravity of the pyramid, it would be necessary to burn, under the boiler of a steam engine, six hundred and thirty chaldrons of coal. There is a foundry which consumes a greater quantity of fuel than this every week!"

The health of Watt seemed to strengthen with his advancing years, while his mental powers retained all their former vigour. Once he thought they were beginning to fail: he then sought for some mode of study to try them by; and testing himself by the Anglo-Saxon language, which is one of some difficulty, he found in the facility with which he mastered it, there was little ground for apprehension. He afterwards constructed a machine designed to copy with despatch and mathematical exactness, pieces of statuary and sculpture of all dimensions. As he made presents of its performances, he used to describe them as "the first attempts of a young artist entering on his eighty-third year. He died on the 25th of August,

1819.

[ocr errors]

A colossal statue of Watt, by Chantrey, from which the engraving at the head of this article was taken, is in Westminster Abbey. The inscription, recording simply his birth and his death, is as follows:

"Not to perpetuate a name which must endure while the peaceful arts flourish, but to show that mankind have learnt to honour those who best deserve their gratitude, the King, his Ministers, and many of the Nobles and Commoners of the realm, raised this monument to Jaines

No less than five statues have been erected to Watt's memory. The benefits conferred on mankind by his labours, have been described by many eminent men, in terms of the highest panegyric. It may, however, be well to observe, particularly for the sake of the youthful reader, that the sketch of his course now given, is one that may serve to refute a popular error. The natural endowments of some men are obviously superior to those of the multitude; but it ought not to be assumed, as it often is, that to these alone great success in life is to be traced. On the contrary, it is to the diligent and unwearied culture and improvement of the powers God has bestowed, that distinguished persons are mainly indebted for their celebrity and usefulness. The harvest is reaped in these instances, as in others, not as the result of spontaneous and exuberant growth, but as the reward of solicitude and toil. Watt was no less remarkable for his indefatigable labours, than for the early activity and versatility of his powers. It may indeed be questioned whether the latter were not far surpassed by the former. When sir Isaac Newton was asked how he discovered gravitation, he answered, By always thinking about it," and, says M. Arago, "in these few simple words of the immortal author of the Principia, we may lay open to the eyes of all, the true secret of men of genius." Let no one, then, suppose that either the inferiority or the superiority of his powers, exempts him from diligent and continued effort. It is with all, a matter of solemn obligation to improve to the utmost every gift of the all-wise and gracious Creator.

66

It ought, at the same time, to be clearly perceived, that the welfare of the soul should receive the first and chief regard. Compared with eternal salvation, all the honours of this life are lost in abject insignificance. The Christian is the highest style of man; and eminence in piety is to be traced to the Divine blessing on "patient continuance in well doing.'

At the commencement of a new year, then, let us all be concerned to enter on a

new career.

There is not one of us who | emanates from Him of whom it is written, "Thou hidest thy face, they are troubled: thou takest away their breath, they die, and return to their dust. Thou sendest forth thy spirit, they are created: and thou renewest the face of the earth," Psa. civ. 29, 30,

may not do more than he has hitherto accomplished, and that with a simpler reliance on Him who is Almighty. Let each one, therefore, begin with himself, and then he may listen to the words of the poet, as he recurs to the past:

"Wake thou that sleepest in enchanted bowers,
Lest these lost years should haunt thee on the
night

When death is waiting for thy numbered hours,
To take their swift and everlasting flight;
Wake, ere the earth-born charm unnerve thee
quite,

And be thy thoughts to work divine address'd;
Do something, do it soon, with all thy might;
An angel's wing would droop, if long at rest,
And God himself, inactive, were no longer bless'd.

Some high or humble enterprize of good
Contemplate, till it shall possess thy mind,
Become thy study, pastime, rest, and food,
And kindle in thy heart a flame refined.
Pray Heaven for firmness, thy whole soul to bind
To this thy purpose-to begin, pursue,
With thoughts all fixed, and feelings purely kind;
Strength to complete, and with delight review,
And grace to give the praise where all is ever
due."

W.

SPONGES AND ZOOPHYTES.-No. I. SPONGES and Zoophytes are considered as beings lowest in the scale of animal organization; but they are by no means among the least wonderful of the works of the Creator. Indeed, in some respects, they excite more than common interest, as discovering to the reflective mind the utmost simplicity of organization, conjoined with animal, not vegetable life. Their organization is, in fact, surpassed in intricacy by that of many vegetables, perhaps by most; yet, simple as it is, it is only the first of a series of gradations, which leads us through a succession of forms, up to the highest orders, namely, fishes, reptiles, birds, and mammalia.

It is our present design to carry out the subject, to which, brief allusion has been already made. (See Visitor 1840, page 429.) We may begin by observing that naturalists have given the term acrita (a a, negative, кow, crino, to perceive) to a group or assemblage of animals, the lowest in the scale, because in their composition (regarding the assemblage in a general light) no distinct nerves are to be perceived. To this group belong the sponges and zoophytes. The acrita are, with a few exceptions, tenants of the water. Their forms are very varied; but they consist essentially of a gelatinous substance, of which the solid constituents bear but a trifling proportion to the fluid. This gelatine is sometimes unsupported by any kind of framework, but generally it either invests, or is contained in a horny or a calcareous support, which is elaborated from it, and which varies greatly in outward form and appearances.

It has often been said, that nature does nothing per saltum; in other words, that the Almighty has been pleased to show his power in the establishment of a plan of creation, founded upon an increase in the gradual developement of organization. Thus, as we ascend the scale of animated nature, we trace the first appearance, the expansion and the perfection of organs; we discover what are the essential conditions of life, and what are the accessories; with what simplicity of structure vitality may be associated, and with what complexity and perfection of structure it is conjoined. We learn, moreover, that structure itself, whether simple or complex, is the result of the power of God in creation, and that the vital principle

Though no nervous fibres have been detected, still it is most probable that nervous matter, in the form of a subtle fluid, or of atoms beyond our detection, may be blended with the gelatine. True blood vessels do not exist; yet in some groups canals are excavated in the substance of the gelatine, through which absorbed fluids circulate and are carried to a central cavity. This apparatus fulfils at once the double office of aerating the system, (for oxygen is the sine qua non of animal life,) and of supplying it with nutrition; which it cannot be doubted is absorbed and assimilated. In some of the acrita, indeed, a more perfect alimentary and aerating set of organs is present, and their use cannot be mistaken.

The powers of locomotion enjoyed by the acrita differ exceedingly; and many, fixed plant-like, live and die on one spot. None have true limbs, but many have tentacles, or feelers, by means of which they secure their prey. There is no distinction of sexes; and reproduction takes place either by simple division, or by buds termed gemmules, which sprout, and become detached from the parent, and ultimately assume their true and permanent form. In numerous instances,

the acrita present the singular condition | servations respecting the mode in which of compound animals. Groups of living the nutrition and reproduction of the beings vitally united together, consti- sponge is effected. We may add, howtute one animal, if we regard it in some ever, that as every part of a sponge is points of structure; but many, if we re- similarly organized, and, that as every gard it in others The acrita then forms part carries on the same functions, it will the lowest great section of the animal not surprise us to learn that if divided kingdom: and of this section, the sponges into pieces, every portion becomes an are the lowest. independent and distinct being, growing and assuming the characteristics of the species.

The sponges (Porifera) have been regarded by naturalists at no distant date, and are so by some at present, as belonging to the vegetable kingdom; nor can we be surprised at it. Who that takes up a piece of common sponge, as sold in commerce, but would consider it as a sort of vegetable, even if told that when first procured it was covered with a gelatinous film; he would, or might reply, with some degree of force, So are many species of sea-weed, (algæ et fuci,) and he might add, Where is its sensibility, and its motion? it does not betray even the irritability of the sensitive plant, the sunflower, or the daisy that folds at eventide. It is fixed, rooted to one spot, it has no definite alimentary canal, and it cannot even select its food. True! so close, indeed, does the animal kingdom trench upon the vegetable; so nearly at one point do they approximate.

But still there is one important distinction; sponges differ from plants, as do all animals, in the chemical components of their substance. Azote, or nitrogen, enters as an essential element into the composition of animal matter; hydrogen into that of vegetables, carbon and oxygen being common to both. Tested by chemistry, the sponge is truly animal; that is, a living animal jelly, investing a curious frame-work, which it elaborates and builds up, and to which, as it grows, it is perpetually adding. Sponges exhibit a great variety of forms, and often the most fantastic shapes. Fixed plant-like to the rock, they festoon the deep sea caves; they line the walls of submarine grottoes, and hang as grotesque ornaments from the roof; some like inverted goblets, aptly termed Neptune's drinking cups; some like fans, some like globes, and others like intertwined branches of uncouth growth.

The common sponge of commerce is procured in the Mediterranean, and was well known to the ancients, who applied it to the same purposes as we do at present. They used it also as a soft and elastic lining for their heavy brazen helmets. We shall not recapitulate our ob

We have designated the fibrous structure of the sponge, as the framework or rude skeleton of the living animal; and it is to be observed, that the characters presented by this framework, differ greatly in the various species, which indeed are extremely numerous.

In the common sponge the fibres are elastic and horny in their texture, and when highly magnified appear to be tubular. In other species, the framework consists of a firm, inflexible tissue of intercrossing filaments, also tubular, and the living gelatine exhibits bands of a more cartilaginous consistency than ordinary, and is also more or less replete with minute crystallized spicula. The spicula are usually simple needle-like points, but sometimes they are three-pointed, thus:

[blocks in formation]

Multitudes of spicula are placed longitudinally around the internal canals of which they form the walls; they may be obtained by washing a sponge, of which the animal matter is decomposing, or by fusing it before the blow-pipe: they are mostly found to consist of silica or flint, and minute as they are, are capable of scratching glass. In the genus Tethya, the framework consists almost entirely of silicious spicula, and quantities are found in the ashes of spongia fluviatilis spongia tomentosa, and other allied species.

A small portion of silica has been detected in the ashes of the common sponge, as one of the constituents in the composition of its elastic fibres. It appears, moreover, that the proportion of silica increases according to the firmness of the fibres of sponge, and that where these are elastic, animal matter predominates. The forms of the spicula are constant in every species, and consequently become

tests in their identification. In some species, the spicula are calcareous; and whether calcareous or silicious, they assume the forms which the crystals of lime and silica present under ordinary circumstances.

Though every species of sponge has its characteristic figure, still no two individuals of the same species agree in external form, or in the number and precise directions of their large canals. Among the higher animals, as we know every species resembles the rest of its species, in the form of the limbs and teeth; in the length and figure of the ears, tail, muzzle, etc.; and also in the arrangement and colouring of the hairs, spines, scales, or feathers. But this definiteness of figure, involving a constancy in the number and arrangement of composing parts, diminishes in degree as we verge towards the lower groups, and when we arrive at the lowest, we see diversity in the midst of

sameness.

Nor can we be surprised at this, when we reflect upon the condition of the nervous system, and upon the vital laws by which these beings are governed. No two sponges of the same species correspond in figure, or in the number of their canals; for the latter multiply as the animal increases, and circumstances influence developement in one part more than another.

But still though this be the case, there are limits to this law of variation, so that no species puts on the appearance of another. The cup sponges never approach such as are branched, nor these, such as resemble tufts of moss; though two cup sponges are never precisely of the same outline, nor two branched sponges of the same shape, and with the same figure and proportion of their ramifications. In these particulars, sponges resemble plants and trees. We all know an oak by its specific characteristics; but no two oak-trees have the same contour of stem, number and direction of branches, or number of leaves. Thus it is, that while they preserve their genuine specific characters, they luxuriate in individual differences.

Sponges are universally distributed through the ocean; they are to be met with on every rocky coast from the polar circles to the meridian. It is, however, in the intertropical latitudes that they display gigantic forms, and strange or grotesque figures; in the colder latitudes they are smaller, and of firmer and more

rigid texture. They often grow in places which the returning tide leaves dry; but their congenial abode is in sheltered and tranquil spots, in caves, and fissures of rocks, where the water, never ruffled by the storm, is "deeply, darkly, beautifully blue." All sponges, however, are not marine; several species are peculiar to fresh waters, and constitute the genus Spongilla of Lamarck, and Ephydatia of Lamouroux.

The spongilla fluviatilis is not uncommon in clear rivulets, adhering to stones: its colour varies from bright green to pale brown, and, besides, changes according to the action of light. From this circumstance, an able writer in the Magazine of Natural History, inclines to the opinion that these fresh water sponges are really within the pale of the vegetable kingdom, and consequently that marine sponges are so. (See article on the action of light upon the colour of the river sponge, by John Hogg, M.A., F.R.S., L.S.) Dr. George Johnson, in his Natural History of British Zoophytes, advocates the same theory, on the grounds that sponges "have no animal structure or individual organs, and exhibit no one function usually supposed to be characteristic of that kingdom." On the other hand, Ellis, (see Linnean Correspond. vol. i.,) whose labours on zoophytes were rewarded (in 1768) by the Royal Society, the Copley medal being awarded to him, states as the result of his investigations, that the whole sponge is an animal, through the pores and canals of which the water circulates; and this is the belief of most naturalists and physiologists of the present day.

are

Sponges occur abundantly in a fossil state, both in the chalk strata, and in the deposit termed " crag," of Norfolk and Suffolk. Professor Phillips observes, that the interesting remains of sponges nowhere so well developed as in England, and perhaps, nowhere in England so well as in Yorkshire. On the shore near Bridlington, they lie exposed on the cliffs and scars, and being seldom enclosed in flint, allow their organization to be studied with the greatest advantage." M.

EUROPE HAPPILY SITUATED.

EUROPE belongs almost entirely to the northern temperate zone. Its most important countries lie between the fortieth and sixtieth degrees of north latitude.

« PreviousContinue »