ture of the place. In the above table, Mr Anderson's theory is again completely verified-the result of his formula, at 10 o'clock in the morning, being only one tenth of a degree, and for both morning and evening eight tenths of a degree different from the mean minimum. The greatest difference, as usual, is during the spring months, which, however, may be accounted for, from the prevalence of dry north and north-east winds. In assigning this as the cause of a similar difference last year, I expressed my self, I believe, somewhat inaccurately, when I stated, that the hygrometer in dicated a greater degree of dryness than actually existed. This, strictly speaking, is impossible; for Mr Leslie has satisfactorily shewn, that though wind may quicken, it cannot possibly augment, the depression of temperature of the moistened bulb of the hygrometer. Still, however, the prevalence of north and north-east winds may sufficiently explain the anomalies in the above table, inasmuch as a continued succession, for days together, of dry cold air from the northern regions, must augment the dryness of the atmosphere beyond what is natural to this climate, a new wave, as it were, flowing in before the preceding one can receive any sensible augmentation of moisture.

At the risk of being thought a little hobby horsical, I must beg leave again to draw the attention of your readers to a fact which I have on former occasions laboured to establish, and which is amply confirmed by the preceding table. In my observations on the abstract for 1817, I stated, that on an average of fifty-two months, the mean, of the daily extreme temperatures, differed, from the mean of 10 o'clock morning and evening, little more than three tenths of a degree. The difference of the same two means, for the whole of 1818, is exactly three tenths-a quantity so very inconsiderable, especially when the nature of the subject is taken into the account, that I may now, I think, venture to recommend, with still more confidence than formerly, these hours (10 in the morning and 10 in the evening) for the observations of temperature, as the hours that will certainly give the average of the whole year correct to a small fraction. Other hours, indeed, have sometimes been recommended,

some for theoretical reasons sufficiently plausible, and some for no reasons at all; but if a copious induction of facts be of any value in physical science, the periods that I am now recommending are surely entitled to the consideration of meteorologists.

The coincidence between the mean temperature of spring water and the mean temperature of the atmosphere, is very remarkable, the difference be ing only about two-tenths of a degree. During the years 1814 and 1815, I kept a similar register of the temperature of pump-water, raised from a depth of 25 feet, and found the mean to coincide very nearly with the annual mean of the open air; but where the depth is so small as three feet, and the fluctuations, of course, greater, I was not prepared to expect such a coincidence as that which the table exhibits. I am aware, that one year's observations do not afford sufficient data for the establishment of any theory, and shall not therefore venture to speculate much on the subject. I may be allowed to remark, however, that a series of observations on the temperature of water near the surface of the ground, may in time furnish results of considerable importance to agriculture, not only in giving the average heat of the ground for the whole year, but in marking more distinctly, as well as more correctly, the gradual progress of the seasons. The farmer, it is true, can neither hasten [nor retard these; but the observation of years might enable him to ascertain more correctly than he can at present do, how far any season is really forward or otherwise, and teach him so to regulate his operations, as to take advantage of favourable, and prevent in some degree the consequences of unfavourable circumstances.

In the averages of the barometer and hygrometer, there is nothing de serving of particular notice. The mean height of the former during the year is one hundreth of an inch higher than that of 1817; the average of the latter is nearly the same for both years. In a former communication to your Magazine, I proposed and explained at some length a contrivance for constructing Leslie s hygrometer so as to register the extreme points to which it rises or falls in the absence of the observer. Of the practicability of the contrivance I have no doubts, and with

regard to its value, it must obviously be to the hygrometer in its original form, what a self-registering thermometer is to one of the common kind. As it has been satisfactorily shown, however, by Mr Anderson, that any observation of the hygrometer, unaccompanied by a contemporaneous observation of the thermometer, is in reality useless; and as the self-registering hygrometer which I formerly proposed does not afford the means of ascertaining the temperature at the moment the hygrometer reaches its extreme points, I have been led to abandon my purpose of constructing the instrument in that form, for a contrivance which I apprehend will be more useful. I propose to employ two self-registering thermometers, graduated so as to coincide as exactly as possible with the two that I presently make use of for ascertaining the extreme temperatures, and to cover the bulbs of both with wet silk. The whole four being adjusted, the two that are dry will stand higher than the others, in proportion to the dryness of the air, and at the next period of adjustment the difference between the maximum thermometers, reduced from Fahrenheit to the millesimal scale, will shew the state of the hygrometerat, or at least very near, the moment of the maximum temperature, and the difference between the minimum ones will shew the state of the hygrometer at or near the moment of the minimum temperature. It may happen that the results thus obtained will not indicate the state of the hygrometer, at the precise moment of the extreme heat and cold, but they must in general be so very near it, I conceive, that there will be no sensible error in supposing them to be contemporaneous with these temperatures. I hope to be able, at no very distant period, to carry my plan into effect. Meantime I remain, Sir, your obedient servant, January, 13th, 1819.

R. G.

OBSERVATIONS ON THE REVOLT OF ISLAM.*

A PERNICIOUS system of opinions concerning man and his moral government,

The Revolt of Islam; a poem, in twelve cantos. By Percy Bysshe Shelly. London, C. and J. Ollier. 1818.

a superficial audacity of unbelief, an overflowing abundance of uncharitableness towards almost the whole of his race, and a disagreeable measure of assurance and self-conceit-each of these things is bad, and the combination of the whole of them in the character of any one person might, at first sight, be considered as more than sufficient to render that one person utterly and entirely contemptible. Nor has the fact, in general, been otherwise. In every age, the sure ultimate reward of the sophistical and phantastical enemies of religion and good order among mankind, has been found in the contempt and disgust of those against whose true interests their weapons had been employed. From this doom the most exquisite elegance of wit, and of words, the most perfect keenness of intellect, the most flattering despotism over contemporary opinion-all have not been able to preserve the inimitable Voltaire. In this doom, those wretched sophists of the present day, who would fain attempt to lift the load of oppressing infamy from off the memory of Voltaire, find their own living beings already entangled, "fold above fold, inextricable coil." Well may they despair :-we can almost pardon the bitterness of their disappointed malice. Their sentence was pronounced without hesitation, almost without pity-for there was nothing in them to redeem their evil. They derived no benefit from that natural, universal, and proper feeling, which influences men to be slow in harshly, or suddenly, or irrevocably condemning intellects that bear upon them the stamp of power,-they had no part in that just spirit of respectfulness which makes men to contemplate, with an unwilling and unsteady eye, the aberrations of genius. The brand of inexpiable execration was ready in a moment to scar their fronts, and they have long wandered neglected about the earth-perhaps saved from extinction, like the fratricide, by the very mark of their ignominy.

Mr Shelly is devoting his mind to the same pernicious purposes which have recoiled in vengeance upon so many of his contemporaries; but he possesses the qualities of a powerful and vigorous intellect, and therefore his fate cannot be sealed so speedily as theirs. He also is of the " COCKNEY SCHOOL," so far as his opinions are

concerned; but the base opinions of the sect have not as yet been able entirely to obscure in him the character, or take away from him the privileges of the genius born within him. Hunt and Keats, and some others of the School, are indeed men of considerable cleverness, but as poets, they are worthy of sheer and instant contempt, and therefore their opinions are in little danger of being widely or deeply circulated by their means. But the system, which found better champions than it deserved even in them, has now, it would appear, been taken up by one, of whom it is far more seriously, and deeply, and lamentably unworthy; and the poem before us bears unfortunately the clearest marks of its author's execrable system, but it is impressed every where with the more noble and majestic footsteps of his genius. It is to the operation of the painful feeling above alluded to, which attends the contemplation of perverted power-that we chiefly ascribe the silence observed by our professional critics, in regard to the Revolt of Islam. Some have held back in the fear that, by giving to his genius its due praise, they might only be lending the means of currency to the opinions in whose service he has unwisely enlisted its energies; while others, less able to appreciate his genius, and less likely to be anxious about suppressing his opinions, have been silent, by reason of their selfish fears-dreading, it may be, that by praising the Revolt of Islam, they might draw down upon their own heads some additional marks of that public disgust which followed their praises of Rimini.

Another cause which may be assigned for the silence of the critics should perhaps have operated more effectually upon ourselves; and this is, that the Revolt of Islam, although a fine, is, without all doubt, an obscure poem. Not that the main drift of the narrative is obscure, or even that there is any great difficulty in understanding the tendency of the under-current of its allegory-but the author has composed his poem in much haste, and he has inadvertently left many detached parts, both of his story and his allusion, to be made out as the reader best can, from very inadequate data. The swing of his inspiration may be allowed to have hurried his own eye, pro tempore, over many chasms; but

Mr Shelly has no excuse for printing a very unfinished piece-an error which he does not confess, or indeed for many minor errors which he does confess in his very arrogant preface. The unskilful manner in which the allegory is brought out, and the doubt in which the reader is every now and then left, whether or no there be any allegory at all in the case; these alone are sufficient to render the perusal of this poem painful to persons of an active and ardent turn of mind; and, great as we conceive the merits of Mr Shelly's poetry to be, these alone, we venture to prophecy, will be found sufficient to prevent the Revolt of Islam from ever becoming any thing like a favourite with the multitude.

At present, having entered our general protest against the creed of the author, and sufficiently indicated to our readers of what species its errors are, we are very willing to save ourselves the unwelcome task of dwelling at any greater length upon these disagreable parts of our subject. We are very willing to pass in silence the many faults of Mr Shelly's opinions, and to attend to nothing but the vehicle in which these opinions are conveyed. As a philosopher, our author is weak and worthless;-our business is with him as a poet, and, as such, he is strong, nervous, original; well entitled to take his place near to the great creative masters, whose works have shed its truest glory around the age wherein we live. As a political and infidel treatise, the Revolt of Islam is contemptible ;-happily a great part of it has no necessary connexion either with politics or with infidelity. The native splendour of Mr Shelly's faculties has been his safeguard from universal degradation, and a part, at least, of his genius, has been consecrated to themes worthy of it and of him. In truth, what he probably conceives to be the most exquisite ornaments of his poetry, appear, in our eyes, the chief deformities upon its texture; and had the whole been framed like the passages which we shall quote,-as the Revolt of Islam would have been a purer, so we have no doubt, would it have been a nobler, a loftier, a more majestic, and a more beautiful poem.

We shall pass over, then, without comment, the opening part of this work, and the confused unsatisfactory

allegories with which it is chiefly filled. It is sufficient to mention, that, at the close of the first canto, the poet supposes bimself to be placed for a time in the regions of eternal repose, where the good and great of mankind are represented as detailing, before the throne of the Spirit of Good, those earthly sufferings and labours which had prepared them for the possession and enjoyment of so blissful an abode. Among these are two, a man and a woman of Argolis, who, after rescuing their country for a brief space from the tyranny of the house of Othman, and accomplishing this great revolution by the force of persuasive eloquence and the sympathies of human love alone, without violence, bloodshed, or revenge,—had seen the fruit of all their toils blasted by foreign invasion, and the dethroned but not insulted tyrant replaced upon his seat; and who, finally, amidst all the darkness of their country's horizon, had died, without fear, the death of heroic martyrdom, gathering consolation, in the last pangs of their expiring nature, from the hope and the confidence that their faith and example might yet raise up successors to their labours, and that they had neither lived nor died in vain.

In the persons of these martyrs, the poet has striven to embody his ideas of the power and loveliness of human affections; and, in their history, he has set forth a series of splendid pictures, illustrating the efficacy of these affections in overcoming the evils of private and of public life. It is in the pourtraying of that passionate love, which had been woven from infancy in the hearts of Laon and Cythna, and which, binding together all their impulses in one hope and one struggle, had rendered them through life no more than two different tenements for the inhabitation of the same enthusiastic spirit ;-it is in the pourtraying of this intense, overmastering, unfearing, unfading love, that Mr Shelly ..as proved himself to be a genuine poet. Around his lovers, moreover, in the midst of all their fervours, he has shed an air of calm gracefulness, a certain majestic monumental stillness, which blends them harmoniously with the scene of their earthly existence, and realizes in them our ideas of Greeks struggling for freedom in the best spirit of their fathers.We speak of the

general effect ;-there are unhappily not a few passages in which the poet quits his vantage-ground, and mars the beauty of his personifications by an intermixture of thoughts, feelings, and passions, with which, of right, they have nothing to do.

It is thus that Laon narrates the beginning of his love for Cythna,-if, indeed, his love can be said to have had any beginning, separate from that of his own intellectual and passionate life.

An orphan with my parents lived, whose eyes Were loadstars of delight, which drew me home When I might wander forth; nor did I prize Aught human thing beneath Heaven's mighty dome

Beyond this child: so when sad hours were

come,

And baffled hope like ice still clung to me,

Since kin were cold, and friends had now become

Heartless and false, I turned from all, to be, Cythna, the only source of tears and smiles to thee.

What wert thou then? A child most infantine, Yet wandering far beyond that innocent age In all but its sweet looks and mien divine; Even then, methought, with the world's tyrant rage

A patient warfare thy young heart did wage, When those soft eyes of scarcely conscious thought,

Some tale, or thine own fancies would engage To overflow with tears; or converse, fraught With passion o'er their depths its fleeting light had wrought.

She moved upon this earth a shape of bright