-importance to its interefts, have induced the Society to offer the prefent publication as the first part of a volume which was promised to be brought forward every two years.' This circumftance, probably, will not give any great concern to the purchasers of these memoirs :whatever be the fize of the book, they will be fatisfied if the quality of its contents be good, and the price fair in proportion to its bulk.

We shall divide the memoirs, firft, into

PHYSICAL and CHEMICAL Papers.

Reasons for fuppofing that lakes have been more numerous_than they are at prefent; with an attempt to affign the causes whereby they have been defaced. By J. Gough, of Kendal.

Mr. Gough affumes that the prefent continents have emerged from the bottom of the ocean in confequence of fubterraneous convulfions. To this theory, he thinks, it might be objected that the number of lakes, or bodies of water, intercepted between the inequalities of the land, ought to be very confiderable. In order to remove the objection, he confiders, fir, what means are in the poffeffion of nature' for filling up lakes; and then he endeavours to difcover whether any proofs of fuch alterations having taken place are ftill extant.

Lakes are filled up partly by the products of fubaqueous vegetation, and partly by materials, brought from a distance; they have been drained totally, or in part, by the dilapidation of their banks; fo that, wherever the iffuing water could wear down its bed below the level of the bottom of the lake, we find, at prefent, a valley in its room, containing very ftrong proofs of its own formation in the ftratum of fand and pebbles with which its fides are covered.

Mr. G. imagines that the bed of every river would undergo infenfible changes from the friction of its own ftream, after it had ceafed to be deepened by the more manifeft ravages of a torrent, were it not for a contrivance of nature, which he defcribes in the following terms:

When a pebble has been a while depofited in water, it is covered with feveral of the imperfect plants, most commonly with the conferva rivularis, and different fpecies of tremella. These fingular productions of the vegetable kingdom are enabled by fome peculiarities of their conftitution to bear the friction of a stream without receiving the leaft injury: and, to whatever circumftance this property is owing, It is plain that the fabstances in queflion, while they provide for their own fecurity, muft enfure the protection of whatever they envelop. By spreading over every part in contact with the water, they preferve one continued furface, and prefent themfelves entire and uninterrupted to the action of the current; and by occupying the crevices arifing from the inequalities of contiguous ftones, they form a kind of cement, in which the lighter fragments being entangled, are prevented

from

from being moved by every trivial force. Thus is permanence given to the course of every river by this fimple provifion of nature; and bounds are fet to a procefs, which without it must have been unlimited.'

The truth of Mr. G.'s fecond propofition will hardly be difputed. In every country, we find flat lands where there were, probably, at fome remote period, refervoirs of water; often of immenfe extent. Though the fact itself, therefore, be abundantly notorious, we fhall quote what Mr. G. fays on this head, as it contains fome curious and pleafing particulars:

There are many vallies in the north of England, which, if we may judge from their appearance, have formerly been filled with water. The coves which feem fcooped out of the fides of feveral hills are perhaps the most fingular objects of the kind. The entrance into one of thefe places always lies through a narrow pass, between two fteep banks. A rivulet moft commonly flows through this opening, which, in fome cafes, conveys away the fuperfluous water of a bafon lying in the centre of the natural amphitheatre. If the courfe of this ftream be traced to fome part where its declivity is interrupted by a plane, the observer may have an opportunity of discovering what has once been its employment. For he will frequently find it flowing along a channel confiderably elevated by a broad bed of pebbles. The fragments conftituting this ridge are in all probability the remains of a rock, that formerly occupied the opening which is now the entrance to the cove.

Befides thefe, there are other vallies of greater extent, and more diftant from the fummits of the hills, which appear to be the wornout refervoirs of ancient lakes. For, in them, the natural trata of the country are buried under deep beds of fand and pebbles. Their fides are frequently diverfified with little eminences, which, in figure and structure, very much refemble the banks that are thrown up by currents: but their elevation above the neighbouring rivers forbids us to imagine that they were formed by them, as it is not uncommon to meet with small hills of the kind many yards above the limits of the greatest floods, but at the fame time, it is evident that they have been raised by ftreams of confiderable force, as they confift wholly of rolled ftones, arranged in ftrata with beds of fand between them. The fineft fand is found in the lowest and most fequeftered places of thefe hollows, in fuch situations as theory afligns to it on the fuppofition that the bottom of a lake is the leaft agitated by storms, where the water is deepest.

In many places it is as fmall as that thrown up by the fea; but it differs in this refpect--fea-fand is more or lefs mixed with thells, but this contains none, though the lime-ftone that is often found in the neighbourhood abounds with them. From this fa& it may be very properly inferred, that the matter in queftion is of a more recent date than the primitive ftrata of the furrounding country; and that the tides of the ocean were not concerned in lodging it where we now find it. For though it would be folly to feek for fhells in the heaps of pebbles defcribed above, because they would be unavoidably crushed

to pieces, during the formation of these eminences, by the fragments" of which they confist being thrown forcibly together by the currents; yet, it is equally evident, that the gentler undulations of the water would tranfport fach light substances along with the finest particles of tone into the calmeft parts of the refervoir, and there leave them to fubfide together. On this account it is highly reasonable to fuppofe, that the beds of fand here alluded to are not productions of the fea; but that they have been depofited by rivers, which, after running over ftrata in a ftate of decompofition, difcharged all the impurifies collected in their respective courfes into vallies full of water at the time; and that the rubbish, which now covers their fides,' confifts of these impurities, difpofed in their prefent order and arrangement, by the currents of the primitive lakes.'

An account of, and obfervations on, different blue colours produced from the mother-water of foda phofphorata, &c. By Mr. Thomas Willis, of London.

Thefe colours were discovered by an accident of much the fame kind as that which furnished the arts with Pruffian blue.. After extracting all the chryftals of foda phofphorata from a combination of the phofphoric acid with pure mineral alkali, or with the best Spanish barilla, Mr. W. threw away the mother-water as ufelefs. It ran through an iron grate, and, on the pavement beyond, left a blueish colour. This appearance induced him to add some of this mother-water to a folution of alum and martial vitriol, on which a fine blue colour was pro-' duced; the fame effect followed whenever the experiment was repeated, though the colour was not always of the fame beauty and intenfity. When the precipitation was made with the mother-liquor of fal fodæ, a pale blue colour was fometimes produced. It remains, therefore, to be determined, by future experiments, what the nature of the mother-water of foda phosphorata is, and how the phosphoric acid enables the alkali to precipitate iron of a blue colour.-It fhould be added that Mr.W.'s phosphoric acid was obtained from bones burned to a perfect whiteness.

On the action of metallic oxyds and earths on oils in low degrees of heat. By Mr. Peter Henry.

In this useful inquiry, Mr. H. found white arfenic to have a greater power of rendering the unctuous oils clear and limpid than the oxyds of lead and copper. Vitriolic acid precipitated the arfenic, leaving the oil colourless. Litharge, in degrees' of heat above 200°, difcoloured train oil. Earth of alum decoloured the oils more powerfully than most of the metallic oxyds, and equally with any of them. It drew down a mucilage from oil of fpermaceti and linfeed.

Meteorological obfervations made on different parts of the western esaft of Great Britain: arranged by T. Garnett, M. D.

The obfervations and tables brought together under this article form a very valuable contribution toward the advancement of meteorology. We could wish to fee them reprinted, partly in order to diffeminate useful information, and partly to incite perfons, ftationed in different parts of the kingdom, to make fimilar obfervations. It would be ftill better perhaps, if fome perfon would digeft all the information which we poffefs concerning the weather of our island, and publish it in a cheap pamphlet.

The prefent paper is compofed of materials furnished by feveral obfervers; thofe by Mr. Copland, furgeon at Dumfries, are the moft confiderable in bulk and importance. In 1781, this gentleman published a number of remarks, on the weather in the Dumfries Weekly Journal, which are here reprinted with fome additional fpeculations. Mr. C. is of opinion that the changes of the barometer indicate approaching hot and cold, with much greater certainty than dry and wet, weather.

"Every remarkable elevation of the barometer, where it is of any duration, is followed by very warm or by dry weather, and moderate as to wind, or by all of them; but heat feems to have moft influence and connexion; and when it is deficient, the continuance of the other two will be the longer and more remarkable; therefore the calculation must be in a compound ratio of the excefs and deficiency of the heat, and of the dryness of the weather in comparison of the medium of the feafon; and with regard to the want of ftrong wind, itappears to be intimately connected with the laft, as they show that no precipitation is going on in any of the neighbouring regions.' In his 14th and 15th remarks, he had faid

14th. That the barometer being lower, and continuing fo longer than what can be accounted for by immediate falls, or ftormy weather, indicates the approach of very cold weather for the feafon; and alfo, cold weather, though dry, is always accompanied by a low barometer, till near its termination.

15th. That warm weather is always preceded and mostly accompanied by a high barometer; and the rifing of the barometer in the time of broken or cold weather, is a fign of the approach of warmer weather and alfo if the wind is in any of the cold points, a fudden rife of the barometer indicates the approach of a foutherly wind; which in the winter generally brings rain with it.'

In the two following remarks, Mr. Copland had explained certain phenomena from a principle fimilar to that on which Dr. Darwin has fo much infifted: (BOTANIC GARDEN, I. notes P. 79. &c.)

That the falling of the barometer may proceed from a decompofition of the atmosphere occurring around or near that part of the globe where we are placed, which will occafion the electricity of the atmosphere to be repelled upwards in fine lambent portions; or driven downwards or upwards in more compacted balls of fire; or laftly, to be carried along with the rain, &c. in an imperceptible

F 3

manner

manner to the furface of the ear th: the precipitation of the watery parts generally very foon takes place, which diminishes the real gravity of the atmosphere, and alfo by the decompofition of fome of the more active parts, the air lofes part of that elaftic and repulfive power which it fo eminently poffeffed, and will therefore prefs with lefs force on the mercury of the barometer than before, by which means a fall enfues.

• That the caufe of the currents of air, or winds, may also be this way accounted for: and in very fevere ftorms, where great decompofitions of the atmosphere take place, this is particularly evident, fuch as generally occur in one or more of the Welt India islands at one time, a great lofs of real gravity, together with a confiderable diminution of the fpring of the air immediately enfues, hence a current commences, firft in that direction whence the air has most gravity, or is moft difpofed to undergo fuch a change; but it being foon relieved of its fuperior weight or fpring on that fide, by the decompofition going on as fast as the wind arrives on the island, it immediately veers to another point, which then rushes in motlly with an increafe of force; thus it goes on till it has blown more than half way round the points of the compafs during the continuation of the hurricane. For in this manner the Weft India phenomena, as well as the alteration of the wind during heavy rains in this country (fee remar No. 4.) can only be properly accounted for.'

Thefe extracts, we truft, will induce every curious reader to feek farther information in the original paper, to which we muft refer for the tables and remarks of Mr. Gough, Dr. Campbell, and others.

[To be concluded in our next Review.]

ART. XXII. Eight Sermons preached before the University of Oxford, in the Year 1792, at the Lecture founded by the late Rev. John Bampton, M. A. Canon of Salisbury. By John Eveleigh, D. D. Provost of Oriel College, and Prebendary of Rochester, 8vo. pp. 286. 4s. Boards. White and Son.

THE pious founder of this lecture, in providing that, for ever,

eight fermons should be preached annually in defence of the Chriftian faith, and in ordering that one printed copy fhould be given to the head of every college, and one be put into the Bodleian library, certainly intended to furnish, in procefs of time, a complete armoury both offenfive and defenfive, to be used, as occafion fhould require, against all schismatics,

• Mr. C.'s 4th aphorifm is, that the heaviest rains, when of long continuance, generally begin with the wind blowing easterly, when it gradually veers round to the fouth; and that the rain does not then begin to ceafe till the wind has got to the weft, or rather a little to the northward of it,'-when, it may be added, it commonly blows with fome violence.

heretics,