On the Barometer. By RICHARD WALKER, Esq, WATER exists in the atmosphere in two different states, viz. 1st, in a state of chemical combination; that is, so completely incorporated with the air, as to form with it one homogeneous transparent fluid-and, 2dly, in a state of me chanical combination; which is, when the minute particles of water are merely suspended in the air, forming that state of the atmosphere, which is denominated cloudy or misty. The dense state of the air being fittest for the chemical combination above mentioned; clear, dry weather, generally speaking, accompanies the higher degrees of the mercury in the barometer, whilst, a rare state of the air being less capable of receiving the water into chemical combination, it is then merely suspended in a state of mechanical combination, forming clouds, mists, &c. Hence it follows, that, when the mercury stands at or near FAIR, clear dry weather is indicated generally; and when at or near RAIN, cloudy or wet weather; and when fluctuating mid-way, changeable weather. It occasionally happens, however, that the atmosphere is cloudy, and even wet, whilst the barometer is as high as FAIR; and clear and dry, whilst the barometer stands as low as RAIN. The reason of this, in the first instance, is, that the air, having become replete or over-loaded with water, is incapable (by an alteration of temperature, viz. the air and its contents having become colder) of retaining or suspending it in a state of chemical combination; and in the latter case, which happens after rain, succeeding a continued dry state of the atmosphere, which having swept down the vapour with it in its descent; the air, though then in a rarer state, is yet sufficient to retain the proportion of water, now much reduced in quantity, in a state of chemical combination. The particular or more immediate indication of the wea ther which is coming, arises from the alteration which is taking place in the density of the atmosphere, and which the barometer exhibits by the rising or sinking state of the mercury; the weather becoming comparatively clearer as the atmosphere is becoming denser, and duller as the atmosphere is becoming rarer*. * The difference that might be supposed to arise in the height of the barometer from the effects of different degrees of heat on the atmosphere, may in observations of this nature be entirely disregarded, these effects being very nearly equalized by the expansion and contraction of the mercury in the barometer, from the same cause. Hence, 1 Hence, if the barometer were as portable and as convenient for reference as a watch, we should seldom be at a loss to know, at least for short intervals, what kind of weather was coming*. The ordinary range of the barometer in this climate is from RAIN to FAIR; rising however, occasionally, as high. as SETTLED FAIR; and sometimes, though very rarely, as high as VERY DRY: and sinking, occasionally, as low as MUCH RAIN; and sometimes, though very rarely, as low as STORMY. It is scarcely necessary to observe that north and east winds, in consequence of passing to us from a colder climate, and over land, bring a denser, colder, and dryer atmos phere; and south and west winds, coming to us from a warmer climate, and over the sea, bringing a rarer, warmer, and damper atmosphere; and moreover, that the capacity of air for retaining water in a state of chemical combination, is increased by coming from a colder to a warmer temperature; and diminished, by coming from a warmer to a colder tem perature. It must be equally apparent, that the greater or less eleva tion of the clouds depends upon their own degree of density, and that of the atmosphere which supports them. With regard to the immediate causes of the direction and: changes of the wind in this climate, I consider them as involved in too much obscurity and uncertainty to say any thing satisfactorily about them; and with respect to electri city, which though doubtless a powerful agent in meteorolo-> gical effects, I consider it rather as a matter of curious speculation than of practical utility. I have therefore only to add, that by a due consideration of the causes enumerated above, connected with the more obvious effects of the sun's varying influence in raising and dispelling vapours, we may, I think, account pretty satisfacto rily for the various vicissitudes of weather, which mark the different seasons throughout the year; and by the relation of the barometer to those causes, be enabled to foresee, with a considerably greater degree of certainty than is commonly supposed, the different changes of weather which are, at all times, about to take place. As the atmosphere is almost constantly varying in its degree of density; so is the barometer, which is an accurate measure of its density, as constantly varying in its altitude, and should therefore be frequently referred to. New Mode of improving Grass Lands. By Mr. SALTER of Norfolk. (Communications to the Board of Agriculture.) As Mr. Coke, President to the Norfolk Agricultural Society, has expressed himself in terms of approbation so highly gratifying to me upon my method of improving poor pastures and boggy meadows, and particularly when he honoured me with a visit this summer for the purpose of examining a meadow, which was then in its highest state of improvement with a crop growing upon it; I readily comply with your request, and have sent you the best informa: tion I can of the method, which I have pursued now ten years in that line of farming; a method, which originated in accident, but which has ever since been carried on systematically. : At Michaelmas 1795, I entered upon this farm, consisting of upwards of six hundred acres, of which the greatest part. is wet, springy, cold land. There were at that time, about! one hundred acres of bad meadow, so over-run with rushes, sedges, and all sorts of aquatic plants, that no sheep had ever been known to be pastured upon them; whereas, for the last eight years, I have not had a single instance of a rotten sheep. I first cut the rivulet, which runs through the mea-. dows, three hundred and fifty-two rods in length, (reckon ing seven yards to a rod,) and eight feet wide. I also cut: one thousand one hundred and sixteen rods of open drains ; and the turf or sods, which came out of them, 1 laid to dry in the months of February and March; and as soon as dried I gathered them on large heaps of sixty and a hundred loads, and burnt them to ashes. On the &d of April, 1796, I dibbled about two acres of that part of the meadow which was most dry, and immediately I carried on, in half-load tum-¡ brils with broad wheels, about fifteen loads per acre of thei turf ashes: then I sowed sixteen or eighteen pounds of Dutch clover, and four bushels of ray grass; i. e. eight or nine pounds of Dutch clover, and two bushels of ray grass per acre. These I brushed with a pair of harrows bushed, and rolled three or four times with a very heavy roll, in order to make them as firm as possible. Upon that part of the meadow which was boggy and rushy, I laid from eighty to an hundred tumbril loads per acre of sand, fine gravel, and mould, as I could most conveniently come at them, cutting and carrying away every hillock of waste earth which I could find. Having barrowed and rolled this, I dibbled upon every acre two bushels of summer vetches, one bushel of early grey peas, peas, and two bushels of Poland oats, all mixed together; and then sowed Dutch clover and ray grass as I did проп the dry part of the meadow, in which I omitted the oats, knowing they would not have succeeded. In dibbling thus, the holes ought to be four inches square from each other, and from two to four seeds should be put into a hole. Peas and vetches thus growing upon grass land, whether on low meadows or dry uplands, have never failed with me of having excellent effect. They entirely destroy moss, and ameliorate the soil. It is to be observed, that upon dry uplands I omit the ray grass. When the crop is forward in the pod, I mow it for hay; and as soon as it is dry, I put it upon small cocks, and then on to large ones, so as to prevent the leaves from falling off. If I do not want this hay for my sheep, I cut it for my horses; and it is so nutritious, that it serves both as hay and corn. In the year 1803 I grew thirty acres of vetches, peas, and oats, managed as above: the crop was not less than from two and a half to three loads per acre: by a load, you know, I mean as much as a waggon drawn by four horses can carry. In the same year I sowed one hundred acres of turnips three times over, and at last lost my whole crop, except a single turnip. I had 532 breeding ewes to maintain in the following winter Having provided thirty troughs twelve feet long, and a straw-cutting machine, (which with a horse will cut ten coombs an hour), I cut the hay made of the vetches, peas, and oats, and thus fed my sheep, which produced me a greater number of lambs, and a greater quantity of milk for the lambs, than I ever had from turnips. They were kept in the straw-yard from the 10th of October to the middle of April; and thus I kept them last year, and shall always keep them whilst I remain upon a heavy-land farm. They eat the straw well, and make a far better yard of muck, than that from bullocks. It was by much the best muck I ever had, except a yard of muck, where I fatted 220 pigs, by scattering peas about the yard.-As a proof of my success in lambs in the year 1804, my shepherd, Thomas Nunn, gained one of the premiums (five guineas) from the Society. In February, 1805, a seventeen-acre meadow was become solid; I filled up the open drains, and cut nine hundred and ninety-five rods of under-drains, which I filled up part with bushes and part with stones. Upon April 4th, I began to dibble vetches and peas; then carried on about 15 loads per acre of out-hollowing, muck, and mould together; sowed Dutch clover and ray grass, and brushed them as usual: the crop was abundant-I got 63 loads of hay from the 17 acres. This was the meadow which Mr. Coke, Mr. Gurdon, you and other other gentlemen admired so much, and deemed an improve ment in the management of grass land deserving of high com mendation. I will not omit to tell you from what accident this method of managing grass lands originated:-In the year 1784 I had a piece of grass laud eaten up by grubs: I sowed vetches upon it, and barrowed them. They produced so good a crop, that I have continued the practice to the present time. Indeed 1 carry it on in every instance where I can; for whenever my lays of clover fail, instead of breaking them up, I dibble or drill vetches early in the spring. It is worthy of remark, that the ray grass and Dutch clover upon my meadows come much earlier, and grow faster, than the lays upon my arable land. Be assured, that I shall have pleasure in attending you to Reepham to examine your pasture there, in order to salter them, as you are pleased to call my method of improving grass land. P. S. I as often use the drill roll for the vetches and peas, as I do the dibbles: please to observe also that I never plough, pare, or scarify my grass lands. CRITICAL ANALYSIS OF RECENT PUBLICATIONS IN THE DIFFERENT BRANCHES OF PHYSIC, SURGERY, AND MEDICAL PHILOSOPHY, Transactions of the Medical Society of London. Vol. I. Part 1. 8vo. pp. 247. 1810. Maxwell. THE Society has changed the title of its volume, as well as the mode of publishing it. Transactions is certainly a more appropriate term for such a work than Memoirs, and by being favoured with it in parts, at shorter intervals, our curiosity is gratified without our patience being exhausted. The volume commences auspiciously, with a paper from Mr. Mason Good, on Medical Technology. After elo¿quently descanting on the imperfection of our language, and the consequent confusion of our ideas, Mr. Good refers the sources of the corruption to the following heads: "First, the intermixture of different tongues that have no family or |