water and flaked lime, the fand, brick-duft, or other materials, you chufe to employ for the purpose, to the confiftence already prescribed, that is, fomewhat thinner than ufual; then sprinkle into the mix ture your powdered quick-lime; and, laftly, incorporate the whole well together to be used directly. The fecond way is, to mix up the fand, brick-duft, and powder ed quick-lime by themselves in the proportion prefcribed; then adding to them, juft as fast as you want your cement, the proper quantity of flaked lime and water, work the whole up well with the trowel. In this way, the fand, brick-duft, and powdered quick-lime may be kept ready made up in facks, large enough to fill one or two trouglis, fo as scarce to leave the workmen any room to fail in the operation, let them be ever fo ignorant or careless about it. But, I must own, that all I have been faying might be looked upon as an idle declamation in Monf. Loriot's favour, intended merely to heat the imagination, and excite the curiofity of my readers, without any reasonable profpect of my being able to fatisfy it, did I not give fome proofs, that the fuccefs of his cement in real works, of the moft extenfive and various kinds, has not fallen fhort of the merit attributed to it in confequence of a few confined trials. The first thing the Marquis de Marigny thought it his duty to afcertain, with a view of rendering Monf. Loriot's difcovery ufeful to his majefty. and the ftate in general, both in civil and military, private and public architecture, was the furprifing quality attributed to it of being impenetrable to water; of fuftaining and containing that element; nay, of acquiring under it a perfect degree of confistence and tenacity; and all without flawing, or cracking, or fhrinking, or fwelling; and, with this view, he chofe fome, works perpetually expofed to water for his firft trials. He had, it seems, to conftruct in his gardens at Menars, a bafon to fupply a very confiderable hydraulical machine; a canal, from forty to fifty toifes long, to bring water to that bafon; and fome fubterraneous drains to carry off his wafte water*. Now, there was not one of thefe works, in which he did not make ufe of Monf. Loriot's cement; in one part of them, by way of a fimple coating, where nothing more was wanting; in another, to bind together common ftones huddled promifcuously together; and, in a third, to ftop the fluice of a canal he wanted to drain, in order to coat it from one end to another. The effect of the cement used for the laft of theie purpofes, after common mortar, clay, and every other simple or compound fubftance generally used on fuch occafions, had failed, proved extremely fudden and decifive. It had fcarce time to fill up the fluice, when it withstood the water to fuch a degree as to dry and harden completely, and in a very fmall space of time, whilft the contiguous ftones were vifibly fweating at every pore. The dome of a fountain, of very curious conftruction, being found, in confequence of the spongynefs of The toife is equal to fix French feet; and the French foot is almoft three quarters of an inch longer than the English foot. the the ftones of the country with which it had been built, to give way to all the waters which happened to light upon it, and thereby render the leaft ftay under it difagreeable and dangerous, the Marquis had it coped with a layer of this cement; and the effect proved equally fudden and fatisfactory with that just now related with regard to the fluice. The bason we just now took notice of, fituate for the most part on the arch of a vault containing all the moving parts of the hydraulical machine fupplied by it, exhibits another ftriking proof of the great advantages to be expected from this cement; and what adds to the wonder is, that all these trials were made in weather extremely unfavourable to them, viz. in autumn; in the beginning of the winter 1772, and in the fpring of the year 1773, during which the men were often obliged to work in the rain. In the latter end of October, 1772, they had fcarce done coating a bafon in a yard, where the Marquis intended to keep fome water-fowl, when a violent fhower filled it to the height of fix inches and upwards; yet the work never fuffered by this fevere trial; not a drop of the water penetrated; what efcaped, was merely by evapora tion. It will, no doubt, be asked, which of the foregoing compofitions it was, that Monf. Loriot gave the preference to in his feveral works at Menars; and it is but juft I fhould fatisfy him. The cement used in the grand canal of the kitchen-garden, fortyfeven toifes long, feven feet broad, and three deep; in that of the back kitchen garden; in that of the yard to keep water-fowl in; on the outfide of a vault over which there now ftands a fhrubbery; on the dome of the fountain I have alrea dy taken notice of; as, likewife, on the maffy part of a building, which conveys water to the machine; and rifing feven feet within the bafon it fupplies, ferves as a vent, as well as to carry off the water at top to prevent its overflowing, when it is not to be let into the little bason of the machine. ; the cement, I fay, employed in all thefe works, was that compofed entirely of fand and brick-duft, with quick and flaked lime. But, the coatings of this conduit, and the bafon at which it terminates, were made with the addition of powdered charcoal, in the proportion already prefcribed. With regard to the coatings of the terrace walls, and fome other parts of the building, the old plaftering of which, yielding to the moiffure and other affections of the weather, ufed to peel off every winter, he employed nothing in the compofition of them, but the already prescribed quantity of quicklime added to common mortar made of flaked lime and fand, but fomewhat thinner than for common ufe. He likewife employed the fame kind of cement for the placage of a fubterraneous vault; and afterwards coated it over with the very white cement already fpoken of, made with two parts of air flaked lime, one of quick-lime, and one of plafter. And here it is proper I should obferve, that lime flaked by the air alone, and in the fhade, a circumftance easily known by its being found crumbled to an impalpable duft, may be used to advantage for the purpofe of preventing the ce I 2 ment ment from fetting as foon as it otherwife would; a thing of fome confequence in coating, when the operation requires any extraordinary degree of time and precaution. As often as Monf. Loriot had occafion to lay his cement on the outfide of any vaults, over which there might be a neceflity of people's walking, he had recourfe, in compofing it, to coarfer materials than brick-duft, fand, and the like; by which means, without lofing any of its power to prevent the rain and wet from penetrating fuch works, it rendered the paffage along the inclined fides of them lefs difficult and dangerous. By what we have already faid, the reader may easily guess what a great number of ufeful purposes this cement must answer; and what uncommon advantages it muft, of course, afford in every branch of every species of architecture. To begin with the most obvious; let the building be of what nature it will; and let the materials of it, of themselves, afford each other ever fo little hold by their fides, or firm footing, if I may be allowed the expreffion, through the smoothnefs and inclination of their upper and lower furfaces; this cement will, notwithstanding, confer on them a degree of permanency and ftability, which, without it, we could fcarce expect from the best cut ftone. What arches, therefore, may we not expect from the use of it! how manyufeful and agreeable formsmay we not now venture to give them! By means of thiswonderful compofition, we may make them almost as light as we pleafe, and that, too, with the fmalleft, fmootheft, and roundeft pebbles, without any apprehenfions of their yielding, in any fhape, to any reasonable degree of preffure. Not only we may make aqueducts with it, but even pipes of any bore to raise water to any height, by juft proportioning their thickness to the preffure occafioned by these two circumstances. By means of it, we may, in our canals and bafons, and all other works of that kind, fave ourselves the expence of abutments, clays, maftichs, and fuch other works and fubftances, which, after all, decay with time, and of course stand in need of continualrepairs. No doubt, the best way by far would be to use this cement, even in the folid and maffy parts of fuch conftructions; and, when they have been built in the common way, it will be neceffary to look out for the joints before we lay it on them. Every kind of fubterraneous conftructions, whether civil or military, may, by means of this cement, be rendered not only habitable, but even infinitely more healthy, than they generally are, and that, too, though furrounded by water; fo that our cellars, especially thofe under court-yards, and other open places, as likewise our neceffaries, all now fo fubject, the former to be deluged on every rifing of the neighbouring rivers, &c. the latter, to convey infection to a great distance by their contents ouzing through the adjacent earth; all these works, I fay, may be easily cured by means of this cement, equally proper to keep water in or out. In short, what is it we may not make of, or with the affiftance, this proteus matter, and that at one caft? Watering-troughs, ponds for for ftable and poultry yards, refervoirs against fire; wholefome cifterns in fortified and other p aces, where no running or well water is to be had. What floors, what ceilings, what copings, what terraces, and that of any form, may we not promife ourfelves from this fubftance! We now need no longer ufe fuch weighty gutters of stone or lead, and, of course, fuch maffy walls to fupport them; precautions, which, though fo very expenfive, feldom anfwer the purposes for which they are intended. Inftead of proving effectually impervious to rain, or even the common dampnefs of the weather, they often bring to the ground the buildings they were intended to defend. And, in point of ductility, furely, neither tiles nor flates, nor milled lead, can pretend to compare with this cement for rills, drains, fewers, capping for the ridges of roofs, and fuch other works as require a curve or irregular furface. Nay, whole roofs may be formed with it by juft placing the laths a little clofer to each other than ufual, and then laying a coat of it on them ; and, what is more, the flightest timber-work will be ftrong enough to bear the weight of fuch a Covering; a covering, which muft be allowed of fingular utility in places, where people are now obliged to put up with ponderous flagftones ; or a flight fhingle, fo liable to catch fire from every spark. Both the exterior and interior ornaments of our buildings may, likewife, derive from this cement, not only the greatest folidity, but the moft pleafing variety. But, in this ufe of it, care must, no doubt, be taken not to apply it, either in the way of pargetting,, or of ornaments in relievo to any walls, but fuch as are perfectly dry, left it fhould concenter fome deftructive particles, which, in procefs of time, might make their way out; and fuch works themselves fhould have time to dry perfectly, before any frost can get at them. Moreover, this cement, efpecially that kind of it which has powdered ftone in its compofition, is, of itself an artificial ftone, which may be caft in a mould, and formed into balluftrades and pilafters for the fupport of terraces and platforms, and flights of stairs, with all their appendages, both u'eful and ornamental, ftraight and curvilinear; though, for greater fafety, it may not be amifs to beflow a rude iron core on the pilafters, &c. whose flenderness and height may seem to require fuch an addition. We might, likewife, make it, by cafting it in moulds, or fashioning it on the potters wheels, into flower-pots, and even other lefs refidentiary veffels, for gardens and parterres, and that of any colour we like beft. There are feveral of our provinces, and feveral countries in Europe, where there is not a bit of plafter to be found; and where, of courfe, the dearnefs of it has proved an infurmountable obstacle to the execution of a great number of the moft ufeful works, particularly with regard to chimnies. But, henceforward, by means of this difcovery of Monf. Loriot's, any kind of work may be carried on, in any place, with the fame cheapness and eafe, as in districts where plaifter is to be had in the greatest abundance. There is, indeed, one very curious art, that of fculpture, to I 3 which which Monf. Loriot cannot as yet take upon him to affirm, that this cement of his may be made fubfervient fo far as to fupply the place of plafter, clay, and other lefs folid fubftances, liable to fhrink or fwell. It is, however, already paft doubt, that the cement is very proper to obtain the hollow mould's of fuch figures as we would wish to copy; and Monf. Loriot hopes that, with the advice and affiftance of the famous artifts of our capital, he fhall, fome day or other, be able to contribute fomething, on his fide, to the fervice of the art which they fo affiduoufly cultivate. In the mean time, he will always be ready to answer anyletters addreffed to him concerning the poffibility or probability of applying his cement to any other purposes. New Method of raifing early Potatoes. Hope, near Manchester, SIR, A March, 1774. S the culture of potatoes, and particularly of the early forts for the table, has of late become an object of very general attention, I hope the curious account of a new method of obtaining thefe (without the help of hot-beds) contained in the following letter, will not be unacceptable, and that many of your readers will make trial of it this fpring. I am, SIR, Your humble fervant, Copy of a Letter from Mr. Kirk, of Wilderfpool, near Manchefter, to Thomas Butterworth Bayley, Efa. of Hope, F. R. S. Wilderfpool, Jan, 15, 1775. "IN purfuance of your requeft, I now fend you an account of a new method of raifing early potatoes, and doubt not that it will anfwer wherever it is fairly tried. . On the 2d of January, 1772, I made a hot-bed for the forward fort of potatoes, and on the 7th put in the fets, placing a glafs and frame over them, and taking every precaution to defend them from the froft. Of these small potatoes, or fets, there remained about forty in a bafket, which was accidentally hung up in a warm kitchen, and there remained unnoticed till about the 25th of April. I then accidentally obferved the basket, and, perceiving fomething green on the edge of it, took it down, and, to my great furprife, found that the potatoes had fprouted half a yard in length, and that there was a great number of very fmall potatoes formed on the fibrous roots which had grown out. I took them into my garden, and planted them in a rich fandy foi', without any manure. The roots i put into the ground three inches deep, and laid down the ftems that had sprouted horizontally, and covered them with two inches of foil, but left the tops uncovered. Without farther attention they grew furpri fingly. On the 26th of May, I took up the roots planted in the hotbed on the 7th of January. They by no means anfwered my expectations, or paid for the trouble of their culture; but, at the fame time, I was aftonifhed to find the others, which were put into the ground fo lately, to have produced larger potatoes than the roots in the hot-bed. I took up all the roots and picked off the large potatoes from them (which amounted from four to twelve on each root) and then fet the roots again on the fame ground, |