This fly is, according to the Linnean System, a species of the fourth order, Neuroptera, (from two Greek words, signifying a nerve, and a wing,) having four wings, membranaceous, transparent, and naked, reticulated with veins or nerves, and the tail being without a sting.

This fly is about a quarter of an inch in length; head black and small, with two large eyes, which, together constitute two-thirds of the head; antennæ about one-eighth of an inch in length; moniliformes, or like a necklace of beads: the head is joined to the thorax by a long flexible and retractile neck. The thorax is particularly strong, and the insect appears, as it were, high shouldered. Strong nerves appear at the insertion of the wings; the thorax is of a dark orange-colour, with black spots at the insertion of the wings. The wings are four, transparent, with a strong black nerve on the outer edge of the superior wings. It has six legs, of a light orange colour,-the tarsus, or last joint of the leg, has black joints, with a double unguis, or two short claws. The abdomen or belly is of a bright orange colour.

ON THE ACQUIREMENT OF

KNOWLEDGE.

W. C.

In the endeavour to acquire knowledge, it is of importance that we do not suffer ourselves to be bewildered by attempting too many things at once, or by neglecting those gradations in the scale of intellect, without a due regard to which, it is impossible to arrive at the higher departments. We must begin with first principles, and lay the foundation of the edifice in a clear and comprehensive acquaintance with elementary facts.

When science and imagination first unfold their treasures to an individual possessed of aptitude of acquirement, fond of knowledge, and enthusiastic in his admiration of everything elegant and sublime, he is like one who enters a room splendidly illuminated. He is for a while dazzled with the profusion of lights, and the beautiful variety of colours; and it is some time before he can apply his mind to the objects most worthy of his attention. Such, indeed, is the case with most persons in the earlier stages of their intellectual cultivation; and it is of importance to their real improvement, that they reduce their expectations and confine their researches to sober limits. The great secret of doing much, said Locke, is to do one thing at a time.

With a view to the moral influence of scientific pursuits, and to the prevention of those evils which they may be liable to produce, we should never allow our love of knowledge to interfere with our duties, whether they be those which we owe to the great Author of our being, or those which arise from our relations in life. Prudence, and a sense of obligation, -in many instances necessity,-operates as a sufficient guard against this evil. Wherever the love of knowledge is so predominant, as in some cases it is found to be, and the opportunities of acquiring it few and rare, there is no slight danger of with

It is greatly to be lamented that a disposition to cultivate science, independently of all connexion with religion, is widely and alarmingly prevalent. But there should be that practical recognition of religion as a personal concern, and as entering into the education suited to an immortal being, which its nature so justly demands. There is a spirit gone abroad among certain classes, which occasionally vents itself in extravagant terms, as descriptive of that era of light and glory which the diffusion of intellect, by its own agency, is expected to usher in upon the world. It is possible to carry this notion of the efficiency of knowledge and mental cultivation to an extent that will prove not only false, but also in the highest degree injurious. There is a danger lest the young aspirant after distinction should forget that there are other duties to perform than the mere improvement of his own mind,-than the mere expansion of his own faculties,-and that the hour which he employs in prayer and meditation, so far from being wasted, as he may sometimes think, is the hour of all others most profitably spent. In order, therefore, that science may be religiously, morally, and socially beneficial, the pursuits of knowledge, however delightful in themselves, must never interrupt the regular duties of life, and still less those duties which man owes to his Maker. But when these claims have been fully, honestly, and conscientiously met, science may lawfully come in for the surplus of time which remains.

It is essential in a well-regulated mind, and a wellordered frame of character, to guard against a contemptuous feeling with regard to those who are necessarily destitute of literary and scientific endowments. Independently of the testimony of observation and experience, we have the declaration of an apostle, that, at a certain stage, and, for the most part, before habits of sound judgment and mature reflection are formed, "Knowledge puffeth up." There is something in the elevation of genius, and in the dignity of science, which, like the pride of ancestry, is apt to swell the mind with imaginary importance. He who has advanced towards this fancied eminence is sometimes tempted to think that he has a right to despise those who have been left behind in ignorance, or to view with envy and dissatisfaction those who, perhaps, with inferior intellectual pretensions, have been able by other means to ascend to honour and emolument. Without derogating from the excellency of mental endowments, from its superiority over external and adventitious appendages of the human character, it can no more justify a contempt of comparative and unavoidable ignorance in others, than the power of thegreat, or the wealth of the affluent, can justify a similar feeling towards those who are debarred from such advantages.

Happily the temptation to intellectual and literary pride, the moment it is in danger of becoming general, carries with it its own correction. Let knowledge be extensively disseminated-let the whole mass of the people be elevated to the utmost of their capabilities in the scale of intellect, and the possession of a moderate portion of literary taste and scientific information will cease to be an object of distinction. Let it

so cease, and the danger of undue self-complacence will, of necessity, disappear; and the mass of general knowledge thus acquired, will mingle with the prineiples of common sense. Let there be a movement towards the higher regions of intellect, without any attempt to disturb the economy of nature, and to set at nought the collective wisdom of ages, by capricious change;-every planet moving in its appropriate orbit, and every luminary maintaining its allotted place; and, then, though occasionally an erratic star may shoot across the hemisphere, the whole system, thus mentally illuminated, will present a scene of moral beauty to the eye, resembling that girdle of refreshing light which we sometimes see encircling the nocturnal sky,-and its peaceful and accordant play of operations will convey a sound of moral melody to the ear more delightful than the harmony of the spheres.

[Abridged from DAVIES' Estimate of the Human Mind.]

FLIGHT OF THE EAGLE AND

HER YOUNG.

IN the Book of Deuteronomy, we have a very animated and beautiful allusion to the eagle, and her method of exciting her eaglets to attempt their first flight, in that sublime and highly mystic composition called Moses' Song; in which Jehovah's care of his people, and methods of instructing them how to aim at and attain heavenly objects, are compared to her proceedings upon that occasion. "As an eagle stirreth up her nest, fluttereth over her young, spreadeth abroad her wings, taketh them, beareth them on her wings; so the Lord alone did lead him." (Deut. xxxii. 11, 12.) The Hebrew lawgiver is speaking of their leaving their eyrie. Sir H. Davy had an opportunity of witnessing the proceedings of an eagle, after they had left it. He thus describes them :

Two

"I once saw a very interesting sight, above one of the crags of Ben Nevis, as I was going on the 20th of August, in the pursuit of black game. parent eagles were teaching their offspring,-two young birds,—the manoeuvres of flight. They began by rising from the top of a mountain, in the eye of the sun; it was about mid-day, and bright for this climate. They at first made small circles, and the young birds imitated them; they paused on their wings, waiting till they had made their first flight, and then took a second and larger gyration, always rising towards the sun, and enlarging their circle of flight, so as to make a gradually-extending spiral. The young ones still slowly followed, apparently flying better as they mounted; and they continued this sublime kind of exercise, always rising, till they became mere points in the air, and the young ones were lost, and afterwards their parents, to our aching sight."

What an instructive lesson to Christian parents does this history read! How powerfully does it excite them to teach their children betimes to look towards heaven, and the Sun of Righteousness, and to elevate their thoughts thither, more and more, on the wings of faith and love; themselves all the while going before them, and encouraging them by their own example.

[KIRBY'S Bridgewater Treatise.]

ODDITIES and singularities of behaviour may attend genius; when they do, they are its misfortunes and its blemishes. The man of true genius will be ashamed of them; at least he will never affect to distinguish himself by whimsical peculiarities.TEMPLE.

THE LOGAN-ROCK,

CORNWALL.

ONE of the most remarkable objects on the south coast of England, is the celebrated stone near the Land's End, called the "Logan-Rock." This stone, as many of our readers are probably aware, is a huge block of granite, so singularly poised on a sort of pivot, that the strength of one man, if properly exerted, is sufficient to produce a slight rocking motion, or to log it to and fro, whence, no doubt, its name has been derived.

The Logan-rock is situated about seven or eight miles from Penzance, and nearly five from the Land's End. At this spot, called Castle Treryn, from the ruins of one of those ancient fortifications, so common in this part of Cornwall, several huge piles of granite rocks project into the sea, forming a bold and lofty promontory, around which the ocean rushes with a tremendous and incessant roar.

On one of these piles the Logan-rock is situated. It is a large block of coarse granite, of a somewhat regular form, resting on the small flat top of the pile of rocks forming its base; and the actual point of contact is extremely small, to balance so large a mass. From this point, however, coinciding very nicely with its centre of gravity, the stone is as firmly and effectually supported as if it rested on a much larger surface.

It is this circumstance which occasions the curious

property from which the stone derives its celebrity. If a man apply his back or shoulder to the end of the block, he is able, after several successive efforts, to produce a sensible rocking motion in it, notwithstanding its immense weight, which has been variously estimated at from sixty to ninety tons, though we should suppose the former number to be The stone, however, from its nearest the truth. great weight, and peculiar form, still rests firmly, and no exertion which could be readily applied, would produce any greater degree of motion, or much less remove it from its place.

It was this circumstance, no doubt, which gave rise to an idea among the neighbouring peasantry, who still look with a feeling of reverence (probably not unmixed with superstition) on this singular object, that although one man's strength could rock the stone, yet no power whatever was able to remove or displace it.

This popular idea gave rise, some years ago, to a curious incident, with which many of our readers are A lieutenant in the navy, probably acquainted. stationed on this part of the coast, and probably tired with the monotony and inactivity of his employment, determined on the exploit of putting this popular superstition to the test of experiment. He accordingly proceeded with his men to the spot; and, on applying the strength of a party of stout English sailors, the Logan-rock soon gave evidence of the fallacy of the superstition with which it was regarded, and which, like all mere superstitions, was immediately dispelled on being put to the test. The Loganrock was thus removed, though to only a trifling distance, from the spot where it had probably rested ever since the Creation, and the centre of gravity being altered, its rocking property was entirely destroyed.

The affair, however, did not terminate here, as the adventure, when it became known, excited considerable indignation, being regarded as little less than sacrilege by the neighbouring cottagers, whose feelings were probably still further excited, at the idea of losing an attraction which, as it is the means of bringing many visitors to this otherwise barren and

neglected spot, is frequently, of course, productive of some small pecuniary advantage to them.

It was also considered throughout Cornwall as a wanton and mischievous action, thus to deprive the county of an object which, from time immemorial, had been considered one of its greatest curiosities; and in the end, the officer received orders from his superiors, to replace the Logan-rock; a task of no small difficulty when its weight and situation are considered. Ropes and the necessary tackle were granted from Plymouth dock-yard, for the purpose, and, with admirable skill, the gentleman who had displaced it, hoisted the Logan-rock into its former position again, amidst the acclamations of the surrounding neighbourhood.

The form and situation of this singular stone will easily be understood by the reader from the accompanying drawing, which is taken from the opposite pile of rocks, on approaching it from the land. The small vessels shown in the drawing, it may be observed, are the " seine-boats," used during the pilchard fishery, which is carried on to a great extent on this part of the coast, chiefly during the months of August, September, and October.

It will naturally be asked, what is the origin of the Logan-rock, and does it owe its singular properties to design or accident? On this subject different opinions have prevailed. By the antiquary, it has always been considered as the work of art, being a Druidical monument employed in some of the ceremonies and superstitions practised by them, most probably in the trial by ordeal. Without at all disputing that such may have been the use to which it was applied, the geologist, however, considers the Logan-rock to be the work of nature alone, as granite is well known naturally to disintegrate into masses of a somewhat similar form.

To explain this opinion more clearly, we may observe that most kinds of stone have a natural tendency to separate into masses of a particular shape; thus, slate breaks into thin and flat pieces, and granite generally into cubical or tabular blocks, of which, on

the coast of Cornwall, there are numerous examples. These cubical blocks, owing to the action of the elements, have a tendency gradually to become rounded, by the decomposition of the corners or solid angles; and thus rude spheroidal blocks, like the Logan-rock, may occasionally be formed, although an exceedingly rare combination of circumstances will be required in order to produce a block possessing this peculiar property.

This explanation, it will be seen, is founded on strict observation and analogy, and we can therefore have little hesitation in preferring it to one based upon mere theory or conjecture. F. B.

THE RISING MOON. THE moon is up! How calm and slow She wheels above the hill! The weary winds forget to blow,

And all the world lies still. The way-worn travellers, with delight, The rising brightness see, Revealing all the paths and plains, And gilding every tree.

It glistens where the hurrying stream
Its little ripple leaves;

It falls upon the forest shade,
And sparkles on the leaves.
So once, on Judah's evening hils,
The heavenly lustre spread,
The Gospel sounded from the blaze,
And shepherds gazed with dread.
And still that light upon the world
Its guiding splendour throws:
Bright in the opening hours of life,
But brighter at the close.
The waning moon, in time, shall fail
To walk the midnight skies;
But God hath warmed this bright light
With fire that never dies.