The First Course of these Lectures will commence on Tuesday, the 11th October, at Nine in the Morning precisely. The Second Course will begin on the Second Tuesday in February, at the same hour.

The Royal Institution.

ALBEMARLE-STREET.

PLAN

OF AN EXTENDED AND PRACTICAL COURSE OF LECTURES AND DEMONSTRATIONS ON

CHEMISTRY,

DELIVERED IN THE LABORATORY OF THE ROYAL INSTITUTION,
BY WILLIAM THOMAS BRANDE, F.R.S.,

Secretary of the Royal Society of London, and F.R.S. Edinburgh; Professor of Chemistry in the Royal Institution, and of Chemistry and Materia Medica

to the Apothecaries' Company.

AND

M. FARADAY, F.R.S., &c.

These Lectures commence on the SECOND TUESDAY in OCTOBER, at Nine in the Morning, and are continued every Tuesday, Thursday, and Saturday. Two Courses are given during the Season, which begins in October, and terminates in June.

The Subjects comprehended in the Courses are treated of in the

DIVISION I.

following order*.

OF THE POWERS AND PROPERTIES OF
MATTER, AND THE GENERAL LAWS
OF CHEMICAL CHANGES.

1. Attraction-Crystallization-Chemical Affinity
-Laws of Combination and Decomposition.
§ 2. Heat-Its Influence as a Chemical Agent in
Art and Nature.

3. Electricity-Its Laws and Connexion with Chemical Phenomena. § 4. Radiant Matter.

DIVISION II.

OF UNDECOMPOUNDED SUBSTANCES AND THEIR MUTUAL COMBINATIONS. 1. Substances that support Combustion: Oxy. gen-Chlorine-Iodine.

62. Inflammable and Acidifiable Substances: Hydrogen-Nitrogen-Sulphur-PhosphorusCarbon-Boron.

3. Metals-and their Combinations, with the va rious Substances described in the early part of the Course.

DIVISION III.

VEGETABLE CHEMISTRY.

1. Chemical Physiology of Vegetables.

Mr. BRANDE'S MANUAL OF CHEMISTRY, intended as a Text Book to these Lectures, is published by Mr, Murray, Albemarle-Street.

In the FIRST DIVISION of each Course, the principles and objects of Chemical Science, and the`general Laws of Chemical Changes, are explained, and the phenomena of Attraction, and of Light, Heat, and Electricity developed and illustrated by numerous Experiments.

In the SECOND DIVISION, the undecompounded bodies are examined, and the modes of procuring them in a pure form, and of ascertaining their chemical characters, exhibited upon an extended scale.-The Lectures on the Metals include a succinct account of Mineralogy, and of the methods of analyzing and assaying Ores.

This part of the Course will also contain a full examination of Pharmaceutical Chemistry; the Chemical Processes of the Pharmacopoeia will be particularly described, and compared with those adopted by the Manufacturer.

The THIRD and FOURTH DIVISIONS relate to Organic Substances.-The Chemical changes induced by Vegetation are here inquired into; the Principles of Vegetables, the Theory of Fermentation, and the Character of its Products are then examined.

THE CHEMICAL HISTORY of ANIMALS is the next object of inquiry-it is illustrated by an examination of their component parts, in health, and in disease; by an inquiry into the Chemistry of Animal Functions, and into the application of Chemical Principles to the treatment of Diseases.

The Courses conclude with an ACCOUNT OF THE STRUCTURE OF THE Earth, of the Changes which it is undergoing, of the objects and uses of Geology, and of the principles of Agricultural Chemistry.

The applications of Chemistry to the Arts and Manufactures, and to Economical Purposes, are discussed at some length in various parts of the Courses; and the most important of them are experimentally exhibited. The various operations of Analysis are also shewn and explained.

The Admission Fee to each Course is Four Guineas; or, by paying Eight Guineas, Gentlemen are entitled to attend for an unlimited time. Gentlemen, who are in actual attendance at the Medical and Anatomical Schools in London, are admitted to attend Two Courses of the above Lectures, upon the payment of Six Guineas. Life and Annual Subscribers to the Royal Institution are admitted to the above Lectures, on payment of Two Guineas for each Course; or, by paying Six Guineas, are entitled to attend for an unlimited time.

Further Particulars may be had by applying to Mr. BRANDE, No. 20, Grafton-street, or at the Royal Institution, Albemarle-street.

THE

QUARTERLY JOURNAL.

January, 1826.

ART. I.-On the Lignites. By J. Mac Culloch, M.D., F.R.S., &c. &c.

[Communicated by the Author.]

THE substances included under this term, form the link which, in some measure, unites coal and peat, so distant in geological time and place; partaking at one extreme of the mineral nature of the former, as much as at the other they approximate to the vegetable character of the latter.

The gradation of geological relations among these three combustible families is not indeed very perfect; for while peat is absolutely superficial in position, or covered with very slender deposites of recent soil, the lignites are found under alluvia of a high antiquity, or else are imbedded in the strata which succeed to the coal series. Thus, from the lignites to the proper coal, there is a regular gradation of geological relations; just as by means of the coal of the old red sandstone, we continue an ana logous gradation through the primary strata. The mineralogical, or chemical transition is more perfect: and, in this respect, the lignites hold a station more nicely intermediate between coal and peat; some of the varieties approaching as nearly to the submerged wood of peat in their chemical characters, as they do in their appearance; while, in both these respects, there are varieties at the VOL. XX.

Q

other extremity of the series, scarcely differing from coal, and finally identical with it. The term coal must therefore be taken in a geological light, as applied to that substance in a particular position, and not in a merely mineral sense. This seems the most convenient arrangement, while it also corresponds with the views of other geologists; and thus every stratum or series, generally considered as coal, which has been ascertained to lie in the strata above the magnesian limestone, or red marl, will be here considered as lignite.

While the superior antiquity of every lignite to peat, is proved by the comparative nature of its geological position in all cases, it is also inferred, from the more perfect change to bituminization which the vegetable matter has undergone. And while the production of the former appears to have ceased long ago, that of the latter is matter of daily observation.

Further, to prevent misapprehension respecting the meaning of the term, under the name of lignite are here included, together with all the coals just alluded to, those remains of trees or vegetables, which are buried under alluvial soil or very recent rocks, and which combine, with remains of the vegetable structure more or less perfect, marks of bituminization or charring; which yield bitumen, however modified, on distillation. Thus indeed, even the submerged wood which is found only under the very recent alluvia, and which is more or less connected with peat, would become necessarily included under that substance, whenever it corresponds in its chemical nature; were it not more convenient to distinguish it by geological characters, and to consider it a variety of peat.

The chemical nature of woody lignite will not perhaps be found, in every instance, to correspond as precisely with its geological position as, on this view, it should; and it is also possible that submerged wood may be so far bituminized as to be really undistinguishable from it. This indeed ought to be the case, if the gradation through the whole of these three combustible families is perfect. If it be perfect, the difficulty of distinguishing them, which would be the blemish of a mere arrangement, becomes