but, when the air is fhut out, the furface becomes foft and loofe, fo that the roots of the plants are not able to fupport the weight of the top. When corn is thin fown upon land where there are no weeds, the air at firft has free accefs, and, though the plants fhould tiller in fuch a manner, as to form as many stalks on the field as when the corn is thicker fown, yet the ftalks, ftanding nearer to each other at the root, the air has easier access round the plants. Hence corn fown thin upon clean land, is not so apt to be lodged, as corn that is thick fown, though there fhould be an equal crop on the field. But it must be observed, that, if feed is too thin fown, the corn is as apt to lodge as when it is too thick fown. When feed is fown very thin, and the land in very good order, the plants have fo much room to tiller, that the top becomes too heavy for the root, and falls over almost of itself. Inftead therefore of infifting with the farmers to fow lefs feed than they commonly do, which in fome cafes may be dangerous, they fhould rather be directed to make their land as clear of weeds as poffible, and then thin fowing, fo far as is proper, will follow in course,'

In this manner the Author explains the reasons of every operation in a plain familiar manner, adapted to the apprehenfions of the clafs of men for whom he writes: for which the more remote Scottish farmers, who are ftrangers to the different methods of tillage, are under obligations to him.

In the course of his ftrictures on the horse-hoeing husbandry, Mr. Dickson furnishes a curious hiftorical anecdote of this method of culture being known to the ancients, to whom it was taught in a manner very foreign to the intention of the teach

ers.

Having mentioned the Roman husbandry, upon this occafion, it will not be amifs to obferve further, that a practice refembling horfe-hoeing, prevailed in fome parts of Italy that lie under the Alps. For this we have the authority of Pliny, who informs us likewife upon what occafion it was introduced. The Salaffi, fays he, when ravaging the lands that lie under the Alps, attempting to deftroy the panic and millet, that at that time had fprung up, and were above the ground. When they found that the ordinary ways of deftroying the fruits of the earth were infufficient, they plowed in the corn that was come up: but the very remarkable crop produced by these fields, taught the inhabitants the practice of plowing while the crop was growing. They gave this plowing when the ftalk was beginning to appear, or when the plant had ferft forth two or three leaves. It is natural to fuppofe, that perfons plowing in corn, on purpose to deftroy it, would not be very careful in this operation, but would run the furrows at such a distance from each other, as to leave rows of plants betwixt them untouched.

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touched. These plants, from the culture given by this plow ing, would foon make their appearance; and upon this, as is probable, being carefully hoed, they would branch out and produce a confiderable crop. The greatnefs of the crop naturally led the farmers to plow fome of their corn-fields in the fame manner next year; and this, it would feem, they continued to do every year with success.

Although this fhews that horfe-hoeing was practised by the ancients, yet it does not derogate from the merit and genius of Mr. Tull, who was certainly the perfon that introduced this method amongst the moderns, and who has brought it to fuch perfection, that it may be juftly eftimated a different kind of culture.'

We fhall now difmifs a work, which, if it contains little that may be new to the fouthern parts of Britain, will afford many good practical leffons to the northern husbandman.

Phyfiological Effays and Obfervations. By John Stedman, M. D. Fellow of the Royal College of Phyficians in Edinburgh. 8vo. 2s. 6d. Edinburgh printed, for Kincaid and Bell, and fold by T. Cadell, in London. 1769.

IN

N the first of thefe effays, which treats of the divifions of pulfes, Dr. Stedman gives nearly the fame account of the pulle, which is delivered by the celebrated Dr. Haller *.

His fecond effay treats of menftruation. This fingular appearance in the female oeconomy, has been accounted for by fome from a general, by others from a partial, plethora. Our Author does not clearly adopt either of thefe fyftems, neither does he fhew the fame precifion, as in difcuffing the fubject of the preceding effay.

Á method of measuring proportional quantities of heat, is pointed out in the third effay; and the defign of the fourth and laft effay is to afcertain the infalutary conftitutions of the air, from a defect of winds of the higher degrees.

In the registers of the weather, fays Dr. Stedman, which have been kept with a view to afcertain the remote caufes of of epidemical difeafes, the gravity, heat, and humidity of the air, have been regularly attended to; the quantities of rain, and the direction of winds, have likewife fometimes been noted; but the degrees of winds have frequently been † neglected. It is intended, in this fhort effay, to fhew the impropriety of this omiffion, in these registers.

* Element. Phyfiolog. Tom. ii. p. 247, &c.

+ Dr. Huxham, in his Obfervationes de dere, &c. generally points out not only the leffer degrees, but likewife the ftorms or higher degrees of the winds,

As the caufe of winds hath been frequently a fubject of enquiry among naturalifts in general, fo have their effects upon animal bodies more particularly attracted the attention of medical authors ever fince the days of Hyppocrates.

• When we endeavour to trace the caufes of epidemical difcafes from journals of the weather, if in thefe journals the degrees of winds have been omitted, we are not only unable to draw any fatisfactory conjecture from them, but are frequently led to believe, either that the ftate of the air, or that of difeafes, ought to have been oppofite to that which appears from the regifters.

Thus, when we find, in a journal of the weather, that the barometer hath been very low for a confiderable time, the humidity and heat being at a mean degree, we are apt to conclude this conftitution of the air to have been unwholefome; which is often the cafe, when a low barometer is attended with continucd calms. But when this low ftate of the mercury proceeds from high and ftormy winds, it, for the most part, indicates a falutary conftitution of the air, and, in fo far, the agitation of the air feems to compenfate its defect of gravity.

As to the directions of winds, independent of their force, thofe which move along the fame climates, though with oppofite directions at different times, have been found to acquire particular qualities, according to the nature of the tracts of land or water over which they pafs. But, in latitudes confiderably diftant from the equator, winds coming from oppofite climates are obferved to poffefs different, and, frequently, oppofite qualities, befides thofe which they acquire from caufes common to all winds. This is the cafe with north and fouth winds in the higher latitudes.

The ancients univerfally afcribe a baneful quality to fouth winds; and the learned Hoffman, though living in a much more northern climate than the ancient medical authors, agrees with them in the effects of fouth winds. It must be owned, however, that fouth winds are not fo much to be feared in thefe northern latitudes, nor have north winds always the fame falutary effects with us, that Hyppocrates, Ariftotle, Celfus, and Galen found them to have in the more fouthern climates. With us the good or bad effects of north winds feem to depend on the period of the year in which they blow: for, about the end of the fpring, or the beginning of fummer, when pinching north winds follow a warm ftate of the air, thefe winds are productive of rheums, coughs, and inflammations, affecting chiefly the pleura and lungs. But, from the fummer folftice to the autumnal equinox, or fome time after it, northerly winds are obferved to correct that state of the air which promotes puerefaction, the caufes of which in the air are heat, humidity, and REV. Nov. 1769. continued

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continued calms, or warm fouth winds. The air, when in this flate, feems frequently to be impregnated with a fulphureous gas, which, at times, manifefts itfelf by meteors, corufcations, thunders, and luminous appearances on fwampy grounds.

us.

• North winds, in general, check or retard vegetation with But, in those parts of Afia and Africa which lie next to the Mediterranean fea, thefe winds are favourable to vegetation, as we are told by those who have vifited those countries.

High winds are no where more neceffary than in great cities, and chiefly after long calms; for the feculencies of different kinds, being collected, contract a more noxious quality than can be corrected by winds of the lower degrees.

By a computation of the quantities of winds of particular degrees, made from a regifter of the weather, which had been kept for five years, it appeared that seven months, in two years of that period, were remarkable for a defect of winds of the higher degrees, and bore a finall proportion to winds of these degrees in the fame months of the other three years.'

Our Author then fhews that these two periods were remarkably infalutary; that, in the first, the influenza occurred; and in the fecond, a number of other difeafes prevailed.-The effay concludes with the following obfervations:

We frequently hear of the plague being transported from one place to another in the cargoes of fhips, particularly in balegoods That infection hath been conveyed in this way, hath been fufficiently afcertained. But it may be doubted whether fuch imported infection be very dangerous in the higher latitudes, especially where the air of thefe climates is purified by high winds, which are frequent in mountainous countries. Even in the fouthern countries of Europe, the devastation, that is, fometimes made by that difeafe, feems to depend chiefly upon the conftitution of the air at the time when the infection is communicated.

The great plague at Meffina, in 1743, (which was the lateft in Europe fo far weft as that city,) is faid to have been brought thither by a Genoefe Tartana, and the great mortality. in that place was believed to have proceeded wholly from this imported infection. But the rapid propagation of the disease feems to have been more owing to the ftate of the air for fome time before the arrival of that veffel, and to a predifpofition in the bodies of the inhabitants to receive the infection, than to any other caufe. In the hiftory of that peftilence, it is obferved that fouthern winds, and cloudy weather, had prevailed all that feafon; and that the inhabitants were thus rendered liable to catarrhs, ulcers and tumours about the glands of the throat and fauces, tumours in the parotid and inguinal glands, acrid humours in the lungs, and fevers of a bad kind. From this we

may judge how much the body was rendered fufceptible of new infection; and it is not improbable that the infection from the Genoefe fhip would have had but little, or no effect, had the air been purified by cool and dry north winds, instead of the long continued warm and moist fouth winds. It may be obferved that the account of this state of the air, and of its effects, coincides entirely with thofe of Hyppocrates, and other authors living in those climates.

Now, though the difeafes of the two preceding periods might have proceeded from fomething in the air too fubtile for our investigation, yet these few obfervations feem to be attended with so much probability as may at leaft fuffice to fhew the impropriety of neglecting the degrees of winds in journals of the weather: fince, in judging of the conftitutions of the air, or in tracing the causes of diseases from them, we cannot avail ourfelves of these journals, when thus defective; but may be misled by them.'

N. B. The first and third of these effays are illuftrated with engravings.

Moral and Medical Dialogues. By Charles Collignon, M. D. Profeffor of Anatomy at Cambridge. 8vo. 2s. 6d. Cambridge printed, and fold by Cadell, &c. in London. 1769.

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'HE defign of these dialogues is to shew,-that whatever we complain of in this world, is either not worth complaining of, or what we might easily avoid if we pleased: and that all things are fo contrived, as that we have it in our power to make them fubfervient to our intereft.-A benevolent, but difficult undertaking!

Dr. Collignon, however, makes many ufeful and entertaining, though not many new obfervations; and the execution of his dialogues would have been more fatisfactory, had he not engaged to prove too much.-But let our Readers judge for themfelves.

Pain and fickness are the fubjects of that part of these dialogues which we fhall quote. Cleanthes is the principal fpeaker; Sophronius, Hortenfius, Philalethes, and Ariftus, make up the rest of the company.

HORT. You cannot furprize me more than you have already done; you have opened a fcene quite new to my imagination, and may (for the prefent at leaft) tranfport me whither you will.-I have read, that health for want of change becomes difeafe; nay, that there is a pleafure in madnefs which none but madmen know; but I must confefs these are pleasures I am not eager to tafte.

CLE. Thefe are very violent expreflions it must be allowed; but that fomething fimilar to the first of thefe affertions is not entirely without foundation, is not perhaps to difficult to make appear.

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• HORT.