entitled SCRIPTURE HARMONY; being a concordance of near Half a Million of References, by the editors of the French Latin Vulgate, and German Bibles, and from Blayney, Canne, Scott, Brown, and others; printed so as to interpage with any part of the above Polyglott Bible, or to be used, as a distinct work, with any edition of the Holy Scriptures.'

This beautiful little pamphlet unfolds a plan of typographical combination, for adapting the proposed work to the different taste and convenience of readers, which surprises us by its ingenuity as much as it pleases us by its usefulness. And as to the work itself, it is impossible in our opinion, for any Christian scholar to refrain from highly approving it. It is true that it does not rise to the construction of a Polyglott that should answer all the purposes of critical study, that shouldimbody with Walton's vast work the Versions discovered since his time, and that should accompany them with subsidia corresponding to the present state of Oriental and Biblical learning. Such a Polyglott is an object of desire, but hardly of hope. Private resources cannot be expected, that shall be able to accomplish it. We must wait till better times and nobler patriotism shall apply parliamentary munificence, and the resources of royalty, to literary and Christian objects, upon a broader scale than has yet been known.

The plan of this proposed publication is such, that each purchaser may, at his option, have either the Original Texts and the Versions mentioned in the Title of the Prospectus, presented to his eye in parallel columns, upon a quarto page, or the same printed separately, yet capable of being variously combined in couples, so as to make four duodecimo pocket volumes. The complete quarto volume will be published in parts, amounting to five guineas in the whole; and the small form is to be published in the same way, but its total amount will be about six pounds. The types are exquisitely beautiful. The marginal references annexed to the English Version, include the usual diversities of rendering which our translators thought it advisable to give; and a series of parallel or elucidatory passages, the plan of which, with respect to its novelty, its judiciousness, and its utility, merits high commendation. There is one point on which we feel some objection. We regret the intention of printing the Syriac Version in Hebrew letters. It is a very idle economy in any scholar, to save himself the trouble of learning the Syriac alphabet and points; and the language when printed in Hebrew characters, always appears to us disguised and obscured. There is one consideration, however, which may have influenced the Publisher in this arrangement; namely, the difficulty of printing a due quantity of matter in the Syriac letters, in order to preserve uniformity in the pages.

Art. VI. A Practical Treatise on Gas Light; exhibiting a summary Description of the Apparatus and Machinery best calculated for illuminating Streets, Houses, and Manufactories, with Carburetted Hydrogen or Coal Gas; with Remarks on the Utility, Safety, and general Nature of this new Branch of Civil Economy. By Frederick Accum. Second Edition, pp. 190. Ackerman, 1815.

SOON

OON after the nature and properties of elastic fluids were rendered familiar to the public mind, and when every one came to know that water is composed of oxygen and hydrogen, it was suggested whether the river Thames might not be made use of as the grand source of illumination to the streets of London, by the separation of the hydrogenous or inflammable principle of its waters, and the conveyance of such principle through the several parts of the Town. In that case, setting 'the Thames on fire,' would have been actually accomplished, and we must have sought for some other proverbial banter of extraordinary stupidity. The project of effecting the purpose of lighting London by means of coal, would not seem quite so far-fetched, as the one just referred to; yet, thirty years ago, it would have appeared as being grounded on almost as much of philosophical extravagance. At present, however, the public talk of coal gas light with as much familiarity, and as much knowledge too, as of the light from candles and lamps.

Mr. Accum commences the treatise before us, with a slight dissertation upon a subject which might at first sight seem irrelative to the proposed subject of discussion; and indeed there is some little appearance of book-making in the preliminary matter respecting lamps and candles. It must, however, be admitted, that this discussion serves to familiarize the mind of the reader with the general theory and principle of combustion, and as such, it has not improperly found a place in a popular treatise like the present.

Our Author, then, having first announced the assumption that flame is constituted, in all cases, by the combustion of a gaseous fluid called hydrogen, and that light is more or less perfect, as this combustion is more or less complete, proceeds to consider the action of candle and lamps in furnishing this material; and this investigation leads him to a statement of the comparative advantages of wax candles, tallow candles, and lamps of oil, with the principles upon which depends their difference in illuminating power. As this is a matter of some curiosity, and may be made the subject of nightly observation, we shall extract some of Mr. Accum's own statements on this head.

There are three articles which demand our attention in the lampthe oil, the wick, and the supply of air. It is required that the oil should be readily inflammable; the office of the wick seems to be

chiefly, if not solely, to convey the oil by capillary attraction to the place of combustion; as the oil is decomposed into carburetted hydrogen gas and other products, other oil succeeds, and in this way a continual current and maintenance of flame is effected. When a candle is for the first time lighted, a degree of heat is given to the wick sufficient first to melt and next to decompose the tallow surrounding its lower surface, and just in this part the newly generated gas and vapour, is by admixture with the air, converted into a blue flame. The tallow now liquified as fast as it boils away at the top of the wick, is by the capillary attraction of the same wick, drawn up to supply the place of what is consumed by the cotton. The congeries of capillary tubes which form the wick, is black, because it is converted into coal; a circumstance common to it with all other vegetable and animal substances, when part of the carbon and hydrogen which enter into their composition having been acted upon by combustion, the remainder and other fixed parts are by any means whatever covered and defended from the action of the air. In this case the burning substance owes its protection to the surrounding flame. For when the wick, by the continual wasting of the tallow, becomes too long to support itself in a perpendicular situation, the top of it projects out of the cone formed by the flame, and thus being exposed to the action of the air, is ignited, loses its blackness, and is converted into ashes; but that part of the combustible which is successively rendered volatile by the heat of the flame, is not all burnt, but part of it escapes in the form of smoke through the middle of the flame, because that part cannot come in contact with the oxygen of the surrounding atmosphere; hence it follows, that with a large wick and large flame, this waste of combustible matter is proportionably much greater, than with a small wick and with a small flame. In fact, when the wick is not greater than a single thread or cotton, the flame, though very small, is peculiarly bright and free from smoke, whereas in lamps with very large wicks, such as are often suspended before butcher's shops, or with those of the lamplighters, the smoke is very offensive, and in a great measure eclipses the light of the flame.' pp. 14, 15.

It will be seen, by this account, that candles are in fact lamps, with this difference, that the combustible matter of which the latter are composed, is in a constant state of fluidity, while that of the former becomes fluid only at or near the point of ignition; and that the desirable qualities of candles are, that they should be constituted of materials sufficiently fusible to furnish a point of fluidity for ignition, at the same time that they are not too readily converted into burning matter. The superiority of wax over tallow candles, consists in this, that it is possible to burn a larger quantity of fluid by means of a smaller wick, inasmuch as the compact and less fusible nature of the wax, occasions a cup to be formed for the retention of the melted portion, and thus affords a regular uninterrupted supply of combustible matter, while the wick being small, a less formation of sooty and earbonaceous substance takes place, and, consequently, there is

a more clear and decided combustion. It is too on account of the thinness of the wick, that candles made of wax do not require to be snuffed. As the wick lengthens, the light indeed becomes less vivid and clear, in the same manner as in tallow candles with a large wick, but when its length 'becomes too great 'for the vertical position, it bends on one side; and its extremity, coming in contact with the air, is burnt to ashes.' An improvement in the mode of burning tallow candles has been suggested; namely, that of placing them in an inclined position, that the flame might rise perpendicularly from the upper side of the wick so inclined, and thus occasion a projection of the extremity of the wick into the air, by which it would be burnt to ashes in the same manner as the wick of a wax candle. And in order to prevent the guttering or running down of the tallow from this position, an apparatus has been contrived: we cannot here however afford room to particularize it.

These several methods of procuring light, are, it will be remarked, more or less interfered with, and the procured illumination more or less interrupted, by the media through which the process is effected; but in the case of gas-lights the machinery and the product are so entirely separate, that the effect is produced without any impediment-complete, and at once. Whether, therefore, oil, or tallow, or wax, or coal, be employed as the material of illumination, the principle is identical, and by varying the material we only vary the mode of producing and inflaming the same sort of gaseous product.

The second division of Mr. Accum's work, treats more immediately and particularly of the substance from which the gas is produced.

Pit coal is divisible into three classes. The first is principally made up of bitumen; it takes fire easily, and burns briskly, but does not swell and form itself into coke. Most of the coal from the West of England, is of this class, and it is burnt chiefly in inland counties. It is well adapted for the gas-light illumination; it requires less heat to be carbonized than the Newcastle coal, and gives out less sulphurated hydrogen during combustion. In the second class of coal, there is an inferior proportion of bitumen. These coals cake together into masses; they require more heat for carbonization than those of the first class, and the carburetted hydrogen which they afford, is usually loaded with sulphuretted hydrogen. The best and most economical mixture of coals for domestic purposes, is two parts of this, and one part of the first class. The bituminous coals occasion a vivid and blazing combustion; the other gives a more intense and permanent heat. In the third class of coal, the bituminous principle is exceedingly scanty. Coals of this class consist chiefly of carbonaceous,

combined with much earthy matter. They are not fit for the manufactory of combustible gas.

With regard to the origin and geological theory of coal, we cannot be expected here to engage in any inquiry; but there are some facts pointed out by our Author, from Mr. Edington's treatise, in reference to the tricks of the coal trade, to which we may be allowed slightly to advert. The coals which are taken from the mine round and in large masses, and in the same state put on board of ships, are capable of yielding a much larger measure when broken down into pieces fit for the sack, than when in the pool. On the other hand, the inferior small kind of coal will barely measure out the same quantity as they meted in the pool; so that when a coal merchant, as is sometimes done, offers to give sixty eight sacks instead of sixty three to the room, it must be of the small and inferior kind.

"In coal sheds," (says Mr. Edington,)" though measure as well as the mixing of one kind of coal with another is often scandalous, for the act of parliament does not take the least notice of the small measures. It is a known fact, when a fraudulent dealer orders in a room of coals, for every chaldron of 36 bushels, if he does not send them out at the rate of 42 bushels again, he will be dissatisfied with his measure. This is extremely hard upon the lower class of people, who are only able to purchase a peck or half a peck at a time; and let the measure be ever so bad they have no means of redress.",

Mr. Edington continues to remark, that justice to the purchaser of coals can be done only by the Legislature ordering the sale in all instances to be by weight, and not by mea

sure.

6

Immediately subsequent to the above dissertations, a short analysis of which we have presented to our readers, the treatise before us gives a sketch of the rise and progress of the discovery and application of coal-gas, as a substitute for procuring artificial light.' Mr. Murdoch seems entitled to the credit of being the first to bring the new mode of applying coal-gas to the purpose of illumination into practice, and Mr. Samuel Clegg, of Manchester, has the principal merit as it regards the construction and application of the requisite machinery. Our Author has entered into several calculations, in order to prove that the gas-light is not only more brilliant, but considerably less expensive, than the method of illuminating by oil; and from these calculations we shall select the very accurate statement on this head, given by Mr. Ackerman, the publisher of the present treatise. In a letter to the Author, Mr. A. gives the following account.

In answer to your request with regard to my gas-lights, which