good land in two years. This is only at the rate of 136 bushels of potatoes (fuppofing the fack to be 3 bushels) per acre; and it is well known that three times that quantity has been obtained, and 4 quarters 3 bushels and a half of wheat per acre, which would not be reckoned a great crop on any well-cultivated field. It thus appears that neither the crop of wheat nor of potatoes was so great as if the two crops had been obtained in fucceffive years. Nor is it poffible to cultivate the ground at any time fo perfectly by this half-husbandry, as Mr. Clofe calls it, as could be done by fucceffive crops of potatoes and grain.

We next find an account of fome drilled crops, by Mr. Whitmore. The crop of barley he mentions, which, when drilled in rows at 18 inches diftance, yielded fixty bushels of barley per acre, is a very good one. But Mr. Whitmore, who feems to be but a beginning farmer, has already found out one very material defect that will ever attend the mode of culture he is fo highly enamoured with, that of giving late and unequally ripe grain. After he has had at leaft twenty years experience we shall be much more difpofed to follow his practice, than his advice at prefent. He is certainly in a great mistake, when he fuppofes the roots of barley extend no farther than fix inches in queft of food. Let him confult Tull's experiments, to afcertain how far the roots of plants extend.

The gold medal was adjudged to Mr. Thomas Robins, near Tetbury, Gloucestershire, for the greateft quantity of turnip rooted cabbages per acre. The certified weight per acre is 13 tons 10 cwt. and 76 pounds. This, he admits, is a small produce in comparison of turnips; but he thinks, as it comes into ufe at a time when food is fcarce, the value makes up for the smallness of the quantity. After the turnips were all gone, he found that 200 ewes with their lambs (quere, the average weight of the ewes), could be kept a day on one ton, or twenty hundred weight of these cabbage. The whole value of this crop depends on its keeping as a green food late in the fpring. This is the fact therefore that thould be chiefly attended to, that it may be fully afcertained.

It appears by a letter from Mr. John Rofs, profeffor of church hiftory in the Univerfity of Aberdeen, that the turnipcabbage refifts the feverity of the winter in the northern parts of Scotland.

In the fubfequent article Mr. Wagftaff, of Norwich, communicates to the Society the refult of fome experiments which he had made on cultivating unimproved and healthy foils. Thofe who are poffeffed of foils which come under that defcription, fhould be cautious how they follow his example; for should they attempt it on many foils of that denomination, their

Seventy tons is no very extraordinary crop of turnips,

crops

crops would be-nothing. Certainly some peculiarity, not mentioned in Mr. Wagftaff's foil, has been the cause of its producing fuch fingular crops under the culture he gave it. Ought not the Society to have taken notice of this peculiarity?

Next follows an account of fome experiments on the culture of a giant hemp, which grows to 14 feet high; and of a kind of flax, the feeds of both which were brought from China. But neither of them appears to be adapted to our climate.

The most interefting paper in this department, is an account of the manner of inclofing Rufhley ifland, fituated between Great Wakering in Effex, and Foulnefs ifland; by which two hundred and fixteen acres of land, which were covered every floodtide, but left dry on the ebb, were totally recovered from the fea, and effectually defended againft being ever overflowed by it. This work was atchieved by Mr. John Harriot of Rochford, between the middle of June 1781, and the 17th of January 1782; for which he obtained the Society's gold medal.

Though this would have been reckoned a small undertaking in Holland, where much land has been recovered from the fea that was in a fituation far more difficult to be cleared of water, and fecured from it; yet as fuch undertakings are little known in this country, we think much praife is due to Mr. Harriot for having ventured fo far out of the common road, and fo happily accomplished his aim. As we think the method he followed was fimple, natural, and not very expensive, while it, at the fame time, bids fair for being effectual, we shall briefly give an account of it to our Readers, hoping it may ftimulate fome to follow his example: for we know, from our own observation, that many thousands of acres of valuable land might. be recovered from the fea at a small expence, round the skirts of this our native ifle, and its appurtenances.

Mr. Harriot, very judiciously, adopted the kind of fence fo particularly defcribed in a book, entitled, Effays relating to Agriculture and rural Affairs (publifhed, if we mistake not, about ten years ago), and there demonftrated to be the only effectual mode of refifting, at a moderate expence, the force of water. This contrivance was nothing more than that of forming the fence in the fhape of an oblique inclined plane towards the water. On this principle, Mr. Harriot raised a bank of earth round his little ifle, thirty feet wide at bottom, feven feet high, and four feet wide at top, giving the advantage of the batter, or flope, full two for one on the outfide: that is, every foot in height was drawn in two feet; by this means the violence of the waves is fo much abated, that inftead of beating, fhaking, and tearing the banks, which is the cafe of all that I have feen, they spend their fury in a gentle curl up the flope of the bank.'

See Rev. vol. lvi. p. 179, for an account of those Essays.

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With all due deference to Mr. Harriot's judgment and experience, we beg leave to offer it as our opinion, that the flope here. given to the banks is rather lefs than perhaps it ought to have been; but more especially we should be apt to dread, that the height may prove to be rather too fmall. When a ftrong wind chances to coincide with a high spring tide, we should think there was fome reafon to fear that the fea might be forced over the top of this dike, especially as it must be supposed that it will gradually fubfide fo far as to remain at last of a much less height than it was at firft. Had the base been larger, this defect, if it fhould be afterwards obferved, could have been remedied at a small expence, merely by raifing it higher; but in this case, to give much additional height would weaken the fence by bringing it too near to the perpendicular. These remarks we throw out merely with a view to direct others, who may afterwards be induced to attempt undertakings of this fort; and to. remove any objections that may arife to the practicability of effecting fuch a fence with fafety, fhould it chance (which we fincerely hope will not be the cafe) that any accident should hap pen to this new acquifition.

We hope Mr. Harriot will fucceed, by the plan which he has adopted, of at last obtaining fresh water in his pond; but he muft not expect it for fome time to be entirely fo. We do not ap-. prehend that the faltnefs he complains of is occafioned by per-. colation through the foil at bottom, feeing the lining preferves. water fo well from finking through it, but from other very obvious caufes. The whole of the earth that is in this ifle has been fo long drenched with falt water, that every drop of rain which touches any part of its furface, must wash away fome faline particles, fo that all the water which runs into the pond from the furface of the earth, muft neceffarily have a faline impregnation. This will be at the firft very flight, so as to produce no fenfible effect; but as part of the water is evaporated by the fummer fun, that part which remains will become fenfibly affected, fo that it will be neceflary once a year to have the pond cleared of all the water, and of the ftrong faline particles diffolved in it. If this be done, the impregnation will be lefs and lefs annually; fo that, in time, if this mode be adhered to, it will become entirely fweet. Thefe remarks will apply to every kind of ciftern, were it even made of lead, or any other fubftance totally impervious to moisture. In the mean time, Mr. Harriot will do well to be particularly attentive to preferve the water collected from the roofs of his houfes. For that purpose let his ciftern there be fo large as not to overflow; and fo fituated as neither to be expofed to the wind nor the fun, to forward the evaporation of it; and if thus preserved, should his ifland produce any confiderable proportion of corn, good water in abun

dance

dance may be always obtained. For if the open ciftern be drained each feafon, about the beginning of autumn, it will furnifh good water during winter; and if all the winter-water collected from the house be preferved in the ciftern till fummer, it will go a great way *.

We with Mr. Harriot much profit and happiness from his new acquired domain, and that his fuccefs may induce many others to follow his laudable example.

The only remaining paper in this department is a long one from Arthur Young, Efq. being a continuation of the experiments on the clustered potatoe, at Bradfield Hall, Suffolk, from the third volume of thefe Tranfactions.

From the account here given, it appears that Mr. Young is himself but very little converfant in the culture of this valuable plant; that he has been groping his way, to difcover facts that were well known to many perfons long before he began his experiments; and that he has not yet attained a due degree of knowledge on the subject he treats. By thofe who are lefs fkilful than himself, thefe experiments will be read with pleasure; but by fuch as have acquired much fkill in this branch of agriculture, they will be regarded as futile. The general inference he draws on the whole is a juft one; viz. that this plant may be cultivated with profit, perhaps, in every fituation; and that it is not yet fo generally cultivated as it ought to be. Mr. Young's conjecture about the exhaufting nature of potatoes, as a crop, feems not to be well founded. ·

CHEMISTRY.

Under this head we meet with only one Paper: an Effay on portable Furnaces, by the Secretary to the Society, Mr. More. After specifying the great utility of portable furnaces, and giv ing an hiftorical account of the means that have been adopted for rendering the fe as perfect as poffible, the ingenious Mr. More mentions a very effential improvement which he has made upon them; viz. to have the body of the furnace lined with a thin coating of fire bricks, properly fhaped for the purpose, inftead of the luting that Dr. Black of Edinburgh, and fome others,

*Twenty-eight inches of rain is about an average of what falls in moft parts of Great Britain in a year. If fo, each fquare foot would yield 4032 cubic inches of water, which is 17 gallons and a half nearly, or 157 gallons for each fquare yard of roofing, measured horizontally; fo that each yard in length of a house which was 21 feet, or seven yards wide, would afford 1099 gallons or about 17 hogfheads a year of courfe every 100 yards in length of fuch a building fhould afford 17 hundred hogfheads of water; which, fuppofing the pond water to be good for eight months, would leave about 8 hogsheads a day for the confumption of fummer, if it were neither fuffered to run to wafte Mor evaporate.

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have

have recommended. This, he obferves, can be got at a very fmall expence in London, and feems to be well calculated for answering every purpose that can be wanted in fuch kind of fur

naces.

POLITE ARTS.

Under this head, we find a defcription of an apparatus for enabling blind perfons to perform operations in arithmetic with eafe and celerity, by Thomas Grenville, who has the misfortune to be himself blind. It differs in feveral refpects from Saunderfon's numerical board, and is an improvement of it. The board is perforated full of holes, in exact lines, horizontally and perpendicularly. The lines confidered horizontally denote units, tens, hundreds, thousands, &c. reckoning from right to left, as ufual. And the perpendicular lines permit the figures to be placed below each other, as is ufual in every account. Pegs are made to fit these holes, on the head of each of which pegs is printed the figure (number) it reprefents, fo as that, to a perfon who has the ufe of fight, the account can be seen at once. The figures are diftinguished by the blind perfon, by means of certain pins placed in the heads of thefe pegs, which it is unneceffary for us here to enumerate. Between the rows of boles for thefe pegs are rows of fmaller holes, adapted to receive the bent ends of fmall wires, which perform the part of lines, placed either horizontally or perpendicularly, as is neceffary for any arithmetical operation. The box is formed into proper divifions for holding the pegs and wires, and is doubtless a most useful apparatus for those whom it was intended to affift; for there can be no doubt but that any blind perfon, with a little attention, by means of this fimple apparatus, may perform every arithmetical operation that could be performed by him if he had the use of fight.

We cannot help regretting that the Society did not cause the plate, which illuftrates it, to be fo engraved, as that the parts of it might be felt by the band (in the ftile of paper maché) for the ufe of the blind, who may be defirous of forming an idea of it. This could have been done by means of printers' lines, and dots, even without engraving at all; for by means of thefe, if done upon dry, thick paper, much preffed in the working, the lines would have been diftinctly perceptible by the finger.

MANUFACTURES.

Under this head, we meet with an interefting account of the manner of managing filk-worms in England, by Mifs Henrietta Rhodes, of Cann Hall, near Bridgenorth; in which are ascertained feveral important facts relating to this animal, that were not before fufficiently, if at all known, and will open views to the fpeculator, big with future confequences to the profperity of the manufactures of this country.

The