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fiant. He then makes a mixture in this proportion, and exposes it to the action of heat till the olefiant gas is decomposed--and he finds, of course, that it has increased by the quantity of olefiant gas in the original mixture-which only proves, that the olefiant gas has changed, by decomposition, into double the quantity of hydrogen ;-which he knew beforehand must be the case,—and that the remainder is the hydrogen which he himself put into the mixture, and the quantity of which he might, therefore, have guessed without this process. He goes on to expose the mixture with chlorine to the action of light-and finds, after the chlorine and olefiant gas have been absorbed, that the original quantity of hydrogen remains in the jar-thus demonstrate ing that there are six of the one and half a dozen of the other, It surely would have sufficed, if he had told us that, upon submitting chlorine and oil gas to the action of daylight, after the chlorine and olefiant gases were absorbed, the remainder proved to be one-third of the original quantity of the oil gas of pure hydrogen-or of hydrogen mixed with other gases, as the case might be.
The latter part of Mr Brande's paper relates to the illuminating and heating powers of the olefiant, the coal, and the oil gases. As some of his results may prove useful in a practical point of view, we shall shortly detail them. The first point is to ascertain the quantity of gas consumed in a given time. For this purpose, a gasometer, with regulating weights which hang over pullies on each side, was used. It contained about 5000 cubical inches of gas, and had jets of different dimensions attached to it, which were furnished in the usual way with stopcocks, The pressure was measured by the difference in the level of the water within and without the reservoir, to which a graduated scale was attached. The gasometer being first filled with olefiant. gas, the stopcock of a jet having a single perforation of oth of an inch diameter was turned, and the stream which issued from it inflamed ;-the pressure was equal to a half-inch column of water. The light was so regulated as to be equal to that of one wax candle, the intensity being ascertained by a comparison of shadows. In these circumstances, the consumption of gas was found to be 640 cubical irches in an hour;-with oil gas, under the same circumstances, the consumption was 800 cubicat inches in an hour. We are not informed how much coal gas was consumed by a single burner. The next burner employed was on the argand construction, being a circular plate, containing twelve boles, each a'th of an inch in dianieter. "The pressure was the same; and the flame regulated to burn with its
sity, without producing smoke; and yet the consump
of being twelve times as great as in the case where
one jet was used, was only 2600 cubical inches in the hour the light being found equal to that of ten wax candles. We can easily comprehend that the light should be as much as this
-because the quantity increases in proportion to the elevation of temperature. With an argand burner which gave the light of eight wax candles, the consumption of oil gas was formed to be 3900 cubical inches in the hour. In the border for coal gas, the apertures require to be larger. Those used by Mr Brande were oth of an inch in diameter: the light was found equal to five wax candles, and the consumption was 6560 cubical inches in an hour.
• It appears from the above data,' says Mr B., 'that to pre• duce the light of ten wax candles for one hour, there will be
required 2600 cubical inches of olefiant gas, 4875 of oil, and • 13120 of coal gas.' Now, we profess oprselves totally unable to comprehend this arithmetic. We take the data for the ole fiant and oil gases to be, that a burner giving a light equal to one wax candle consumes 640, and a burner giring a light.com qual to ten candles, consumes 2600 cubical inches of olefiant gas, in an hour; that is, to increase the light tenfold, the maltiplier must be 4.0625. Now, with the same orifice and pressure, the consumption of oil gas in an hour is 800 cubical inches, to produce a light equal to one wax candle; therefore, it must be $250 to produce a light ten times as great. Perhaps it may be, that the single burner did not produce a light equal to one KIX candle when oil gas was used, although the quantity of gas consumed was greater,-from the intensity of the light lieing. less than in the olefiant gas: but if this be the case, Mr Brande should have so stated it, -as that is the only datum from which we can deduce the consumption when the greater light is produced. In the case of the coal gas, it is certainly erroneous to say, because the consumption in a light equal to fire wax candles is 6560 cubical inches, that therefore double this consumption will be necessary to produce a light equal to ten candles. As well might we contend, that the consumption for a light of one candle being 640, therefore it requires 640 x 10 = 6400 cubical inches, to give a light of ten candles with the olefiant gas, or 8000 cubical inches of oil gas to produce the same light. It may be, that Mr Brande has found by actual experiment, by a proper adjustment of burners-by an ade. quate regulation of stopcocks-by a careful comparison of shadows--that the numbers he has stated are the correct quantities consumed by these different gases in order to produce the same light;-and if so, we have nothing to say ;- but, from the data before us, he has no right to draw these conclusions as matter of calculation.
• One thing, however, may be safely gathered from this paper, that olefiant gas is by far the best for purposes of illumination; but unfortunately it is too expensive to be of much practical use. Oil gas is decidedly better than coal, although we apprehend, if our calculations are right, that it is not so superior to it as Mr Brande would make it appear. He says, that a gasometer containing 1000 cubical feet of oil gas, is adequate to furnish the same quantity of light as one containing 3000 of coal gas.
To ascertain the heating powers of these gases, Mr Brande boiled water over a burner of each, and found, that to raise a quart of water from 50° to 212°, it required 870 cubical inches of olefiant gas-1300 of oil, and 2190 of coal. Hence it is evident, that the air of a room equally lighted by oil and coal gas, will be much less heated by the former than by the latter; a very material consideration, when this species of illumination is introduced into houses. '
In conclusion, we must call the reader's attention to the very curious analogy established in Mr Brande's experiments with the battery, between the operation of the solar and electric light; and we strongly recommend the subject also to the author, exhorting him to pursue this inquiry. In a subject where so little is known as that of Electricity, every new view that can be opened is a matter of high interest and importance; and no fact should be disregarded, which may give farther insight into a field still so imperfectly explored.
Art. X. Lectures on the Dramatic Literature of the Age of
Elizabeth. Delivered at the Surrey Institution. By WiLLIAM HAZLITT. London. Stodart. 1820.
TF Mr Hazlitt has not generally met with impartial justice
from his contemporaries, we must say that he has himself partly to blame. Some of the attacks of which he has been the object, have no doubt been purely brutal and malignant; but others have, in a great measure, arisen from feelings of which he has himself set the example. His seeming carelessness of that public opinion which he would influence his love of startling paradoxes--and his intrusion of political virulence, at seasons when the mind is prepared only for the delicate investigations of taste, have naturally provoked a good deal of asperity, and prevented the due appreciation of his powers. We shall strive, however, to divest ourselves of all prepossessions, and calmly to estimate those talents and feelings which he has here brought to the contemplation of such beauty and grandeur, as none of the low passions of this . ignorant present time should ever be permitted to overcloud.
Those who regard Mr Hazlitt' as an ordinary writer, have little right to accuse him of suffering antipathies in philosophy or politics to influence his critical decisions. He possesses one noble quality at least for the office which he has chosen, in the intense admiration and love which he feels for the great authors on whose excellences he chiefly dwells. His relish for their beauties is so keen, that while he describes them, the pleasures which they impart become almost palpable to the sense; and we seem, scarcely in a figure, to feast and banquet on their • nectar'd sweets. '. He introduces us almost corporally into the divine presence of the Great of old tinie-enables us to hear the living oracles of wisdom drop from their lips--and makes us partakers, not only of those joys which they diffused, but of those which they felt in the inmost recesses of their souls. He draws aside the veil of Time with a hand tremulous with mingled delight and reverence; and descants, with kindling enthusiasm, on all the delicacies of that picture of genius which he discloses. His intense admiration of intellectual beauty seems always to sharpen his critical faculties. He perceives it, by a kind of intuitive power, how deeply soeverit may be buried in rubbish; and separates it, in a moment, from all that would encumber or deface it. At the same time, he exhibits to us those hidden sources of beauty, not like an anatomist, but like a lover: He does not coolly dissect the form to show the springs whence the blood flows all eloquent, and the divine expression is kindled; but makes us feel it in the sparkling or softened eye, the wreathed smile, and the tender bloom. In a word, he at once analyzes and describes,--so that our enjoyments of loveliness are not chilled, but brightened, by our acquaintance with their inward sources. The knowledge communicated in his Lectures, breaks no sweet enchantment, nor chills one feeling of youthful joy. His Criticisins, while they extend our insight into the causes of poetical excellence, teach us, at the same time, more keenly to enjoy, and more fondly to revere it...
It must seem, at first sight, strange, that powers like these should have failed to excite universal sympathy. Much, doubtless, of the coldness and misrepresentation cast on them has arisen from causes at which we have already hinted-- from the
Ess which usrepresentation, hinc on them ins apparent readiness of the author to give up to party what was meant for mankind '--and from the occasional breaking in of personal animosities on that deep harmony which should attend the reverent contemplation of genius. But we apprehend that .
there are other causes which have diminished the influence of Mr Hazlitt's faculties, originating in his mind itself;--and these we shall endeavour briefly to specify.
The chief of these may, we think, be ascribed primarily to the want of proportion, of arrangement, and of harmony in his powers. His mind resembles the rich stronde' which Spencer has so nobly described, and to which he has himself likened the age of Elizabeth, where treasures of every description lie, without order, in inexhaustible profusion. Noble masses of exquisite marble are there, which might be fashioned to support a glorious temple; and gems of peerless lustre, which would adorn the holiest shrine. He has no lack of the deepest feelings, the profoundest sentiments of humanity, or the loftiest aspirations after ideal good. But there are no great leading principles of taste to give singleness to his aims, nor any central points in his mind, around which his feelings may revolve, and his imaginations cluster. There is no sufficient distinction between his intellectual and his imaginative faculties. He confounds the truths of imagination with those of fact--the processes of argument with those of feeling the immunities of intellect with those of virtue. Hence the seeming inconsistency of many of his doctrines. Hence the want of all continuity in his style. Hence his failure in producing one single, harmonious, and lasting impression on the hearts of his hearers. He never waits to consider whether a sentiment or an image is in place--so it be in itself striking. That keen sense of pleasure in intellectual beanty which is the best charm of bis writings, is also his chief deluder. He cannot resist a powerful image, an exquisite quotation, or a pregnant remark, however it may dissipate or even subvert the general feeling which his theme shonli inspire. Thus, on one occasion, in the midst of a violent political invective, he represents the objects of his scorn as : bav. ing been beguiled, like Miss Clarissa Harlowe, into a house of ill-fame, and, like her, defending themselves to the last;'as if the reader's whole current of feeling would not be diverted from all political disputes, by the remembrance thus awakened of one of the sublimest scenes of romance ever embodied by human power. He will never be contented to touch that most strange and curious instrument, the human heart, with a steady aim, but throws his hand rapidly over the chords, mingling strange discord with most eloquent music.' Instead of conducting us onward to a given object, he opens so many delicious prospects by the way-side, and suffers us to gaze at them so long, that we forget the end of our journey. He is perpetually dazzled among the sunbeams of his fancy, and plays with them