compoft, thus prepared, is laid on the meadows at lefs expence, and that it is more efficacious and durable in its operation, than the fprinklings which, at stated times, they formerly received. For my land, though good, and in fine condition, is light and fandy; and the dunghill-water quickly paffed below the roots of the vegetables, which grow upon its furface. POST SCRIPT. It has been fuggefted to me, that the foregoing discovery has no claim to the patronage of the Agriculture Society, because in measured by the Hudibrastic stand- "What's the value of a thing? I truft, therefore, that the fociety will not, by declining to patronize the prefent difcovery, juftify the farcafm of an ingenious poet of this place, who has humorously charged fome of us with teaching. "By crops increas'd, and profits less, "The way t'enrich the nation." Gunpowder. HE dreadful accidents which Thappen from the explosion of magazines or mills for the manufacturing of gunpowder, make every hint that may tend to the prevention of fuch calamities of the utmost importance to the public. On that account, we fhall fubmit to our readers without further apology the following facts, which have already appeared in fome of the public papers. this manufacturing county it may Caution in building Magazines for eventually tend to check the cultivation of land, by robbing it of one fpecies of manure. But I conceive the operation of it will be entirely the reverfe: for it will promote the collection of every putrefcent article, and thus augment the farmer's dunghill, at the fame time that it excites a more univerfal attention to the preservation of muck water; the refervoirs for which are yet few, and have been made chiefly by thofe who follow husbandry for amufement, and not as an occupation. The public therefore will be gainers both by the faving, and by the acquifition; and a twofold branch of rural economy will be established, at once lucrative to the husbandman, and important to the artist and manufacturer. But admitting all the fuppofad force of the allegation, it muft furely be acknowledged, that the' main defign of our inititution is to increase the productiveness of agriculture, by ftimulating the farmer to every beneficial undertaking, confiftent with his profeffion. Now in this cafe, the beneficial is beft "A gentleman, in a letter from Withington, in Gloucefter fhire, fays, an accident, which happened to me a few days fince, may fuggeft, perhaps, an ufeful caution to fome of your readers. On the table I was writing at, food a fmall glafs decanter, and near that lay my handkerchief; the fun (through a fash-window, which was down, and at a confiderable diftance) fhone full upon the decanter, which, collecting the rays into a point or focus, fet fire to the handkerchief, and, if I had not been in the room, might have had very ferious confequences.” Thus far the writer; and, to confirm the fact, I fhall mention a melancholy event which happened fome years ago in Surrey. the Abut a mile from the place were feveral mills for making gunpowder; one morning whole neighbourhood was alarmed by a violent explofion, which fhook the houfes for feveral miles round, and was followed by a column of fmoak and fire, which towered high in the air, and was vifible at a vaft diftance. When the concuffion was over, I vifited the spot, and beheld the mangled bodies of four poor men, thrown at the distance of more than 100 yards from each other, whofe fcattered limbs were collected together, and buried in one common grave in a church-yard belonging to the parish. In taking a view of the other mills, which were left ftanding, I obferved that fome of the windows were glazed with very coarse glafs, full of convex blifters; and, as the day of this dreadful calamity was remarkably hot, I thought it not unlikely that a focus might be formed through one of thefe glafs blisters, which would easily fet fire to fome of the gunpowder, which thefe poor men were granulating in fieves when this unhappy cataftrophe befel them. This conjecture I remember well to have made at the time, and, to fhew that it was very poffible, as foon as I got home I twifted up fome gunpowder in brown paper, and fet fire to it through a decanter of water, by the focus which the fur. formed upon the paper till it took fire, and went off with an explofion. This event, and the hint from the gentleman in Gloucefter fhire, convince me that the wine dows of all buildings containing fuch combuftible materials, fhould be only towards the north, where the fun can never produce the like effect. To the above we will add a circumftance which happened about twenty-five years ago in Norfolk. A gentleman, who had been entertaining fome friends after dinner, invited them to take a walk, leaving a decanter half full of water on the table. The fervant, who went in to clear away, to his great furprize found the windowfhutters on fire, occafioned by the rays of the fun, which fhone full upon the decanter, and which, having thus fet the fhutters in a blaze, might foon have deftroyed the whole houfe, had it not been timely difcovered. It is alfo a well-known practice at Oxford, where firing is very dear, for the fmoakers to light their pipes, during the fummer months, by the help of a decanter of water. merce, and fo particularly fituated, there must neceffarily be many fhipwrecks: every hint by which the diftrefs of our fellow-creatures may be alleviated, or any faving of property made to individuals in fuch fituations, fhould be communicated for their good. As the members of the Royal Society have it in their power to make fach hints moft univerfally known, I have been induced, from their readiness to receive every useful information, to lay before them a particular account of the fuccefs attending a method for the fafe removal of ships that have been driven on shore, and damaged in their bottoms, to places (however diflant) for repairing them; I hope, therefore, they will excufe the liberty I have taken in prefenting this to them. Should the fociety honour me by recording it, it will make me the most ample fatisfaction for my attention to it, and afford me the greateft pleafure. On January the 1ft, 1779, in a moft dreadful form, the York Eaft Indiaman, of eight hundred tons, homeward bound, with a pepper cargo, parted her cables in Margate Roads, and was driven on fhore, within one hundred feet of the head, and thirty feet of the fide, of Margate Pier, then drawing twenty-two feet fix inches wa ter, the flow of a good spring tide being only fourteen feet at that place. On the 3d of the fame month I went down, as a fhip-builder, to affift as much as lay in my power my worthy friend Sir Richard Hotham, to whom the fhip belonged. I found her perfectly up right, and her fhere (or fide appearance) the fame as when first built, but funk to the twelve feet water mark fore and aft in a bed of chalk mixed with a stiff blue clay, exactly the shape of her body below that draft of water; and from the rudder being torn from her as fhe ftruck coming on fhore, and the violent agitation of the fea after her being there, her ftern was fo greatly injured as to admit free accefs thereto, which filled her for four days equal to the flow of the tide. Having fully informed myself of her fituation and the flow of fpring tides, and being clearly of opinion fhe might be again got off, I recommended, as the firit neceffary ftep, the immediate difcharge of the cargo; and, in the progrefs of that bufinefs, I found the tide always flowed to the fame height on the fhip; and when the cargo was half discharged, and I knew the remaining part fhould not make her draw more than eighteen feet water, and while I was obferving the water at twenty-two feet fix inches by the fhip's marks, fhe inftantly lifted to feventeen feet eight inches, the water and air being before excluded by her preffure on the clay, and the atmosphere acting upon her upper part equal to fix hundred tons, which is the weight of water difplaced at the difference of thofe two draughts of water. The moment the fhip lifted, I difcovered fhe had received more damage than was at first apprehended, her leaks being fuch as filled her from four to eighteen feet water in one hour and a half. As nothing effectual was to be ex pected pected from pumping, feveral fcuttles or holes in the fhip's fide were made, and valves fixed thereto, to draw off the water to the lowest ebb of the tide, to facilitate the difcharge of the remaining part of the cargo; and, after many attempts, I fucceeded in an external application of sheep skins fewed on a fail, and thrust under the bottom, to ftop the body of water from rushing fo furiously into the ship. This business effected, moderate pumping enabled us to keep the fhip to about fix feet water at low water, and by a vigorous effort we could bring the hip fo light as (when the cargo fhould be all discharged) to be easily removed into deeper water. But as the external application might be difturbed by fo doing, or totally removed by the agitation of the fhip, it was abfolutely neceffary to provide fome permanent fecurity for the lives of those who were to navigate her to the river Thames. I then recommended, as the cheapeft, quickest, and most effectual plan, to lay a deck in the hold, as low as the water could be pumped to, framed so folidly and fecurely, and caulked fo tight as to swim the hip-independant of her own leaky bottom." Beams of fir- timber, twelve inches fquare, were placed in the hold under every lower deck beam in the fhip, as low as the water would permit; thefe were in two pieces, for the convenience of getting them down, and alfo for the better fixing them of an exact length, and well, bolted together when in their places. Over thefe were laid long Dantzic deals of two inches and an half thick, well nailed and caulked. Against the fhip's fide, all fore and aft, was well nailed a piece of fir, twelve inches broad and fix inches thick on the lower, and three inches on the upper edge, to prevent the deck from rifing at the fide. Over the deck, at every beam, was laid a cross piece of fir timber, fix inches deep and twelve inches broad, reaching from the pillar of the hold to the fhip's fide, on which the fhores were to be placed to refift the preffure of the water beneath. On each of thefe, and against the lower deck beam, at equal distance from the fide and middle of the fhip, was placed an upright fhore, fix inches by twelve inches, the lower end let two inches into the cross piece. From the foot of this fhore to the fhip's fide, under the end of every lower deck beam, was placed a diagonal fhore, fix inches by twelve, to eafe the fhip's deck of part of the ftrain by throwing it on the side. An upright fhore, of three inches by twelve, was placed from the end of every crofs piece to the lower deck beams at the fide; and one of three inches by twelve on the midship end of every cross piece to the lower deck beam, and nailed to the pillars in the hold. Two firm tight bulkheads or partitions were made as near the extremes of the fhip as poffible, The ceiling or infide plank of the fhip was very fecurely caulked up to the lower deck, and the whole formed a compleat fhip with a flat bottom within fide to fwim the outfide leaky one; and that bottom being depreffed fix feet below the external water, refifted the fhip's weight above it, equal to to five hundred and eighty-one tons, and fafely conveyed her to the dry dock at Deptford. Since I wrote the above account, I have been defired to use the fame method on a Swedish fhip, ftranded near Margate on the fame day as the York Eat India-man, and fwim her to London. As this fhip is about two hundred and fifty tons, and the execution of the bufinefs fomething different from what was practifed with regard to the large fhip, I hope it will not be thought improper to defcribe it. As this fhip's bottom was fo much injured, having loft eight feet of her ftern-poft and all her keel, feveral floor-timbers being broke, and fome of the planks off her bottom, (fo as to leave a hole big enough for a man to come through) feveral lower deck beams being likewife broke, and all the pillars in the hold broken and washed away; I thought it neceffary to connect, in fome degree, the shattered bottom with the fhip's decks, not only to fupport the temporary deck by which the was to fwim up, but to prevent the bottom being crushed by the weight of the fhip when he was put upon blocks in the dry dock: to effect which, after I had put across twelve beams of fir, fix inches by twelve, edgeways, one under every lower deck beam of the fhip, and well faftened them to the fhip's fide, I placed two upright pieces to each beam of fix inches by twelve, fecurely bolted to the fides of the keelfon, and fcored fix inches under the fhip's lower deck beams, and three inches above the beams of the VOL. XXIII. temporary deck, and well fastened to each: then the deck was laid with long two-inch Dantzic deals, and well nailed and caulked; the ship's infide plank was well caulked up to the lower deck. A piece of fir, of twelve inches broad and two inches thick on the upper, and four inches on the lower edge, was well nailed to the fhip's fide all fore and aft, and well caulked on both edges to prevent the fide of the deck from leaking, or being forced up by the preffure of the water against the deck, a twoinch deal or crofs piece was laid over every beam from the fhip's fide to the uprights at the middle line; then, at equal diftance from the fide and middle line, pieces of fix inches fquare, as long as could be got down, were put all fore and aft on both fides, scored two inches over every cross piece, and well bolted through the cross piece and deck, and into the fir beams. From this fore and aft piece or ribband to the fhip's fide, and from it to the uprights in the middle, were placed two rows of diagonal fhores, fix inches fquare, the heels of which were fecurely wedged against the fore and aft piece or ribband, which afforded fufficient fupport to the temporary deck without any other hores. Two bulkheads or partitions were built, as far as the fore-maft forward, and mizen-maft aft, well planked, fhored, and caulked, to refift the water. As decks laid in this manner, and in fo much hurry as the time of low water requires, will of confequence leak in fome degree, and as that leakage, washing from fide to fide, will caufe the fhip to lay along, I fixed a two-inch K |