tioned, eyes large, and of a sparkling black, thin lips, a nose rather high than flat, There is no fuch difference of climate between Abyffinia and Negroland as to produce thefe ftriking differences. At any

rate, there must be a confiderable mixture both of foil and climate in these extenfive regions; and yet not the leaft mixture is perceived in the people.

USE.

Some Extracts, from a practical Essay on a Cement, and Artificial Stone, justly fuppofed to be that of the Greeks and Romans, lately redifcovered by Monf. Loriot, Mafter of Mechanics to his moft Chriftian Majefty; for the cheap, eafy, expeditious, and durable Conftruction of all Manner of Buildings, and Formation of all Kinds of Ornaments of Architecture, even with the commoneft and coarfeft Materials. Tranflated from the French Original, lately published, by the exprefs Orders of that Monarch.

Notwithfinding the grahich

the arts have attained within a few centuries, it cannot be denied, that in looking over the writings of the ancients, and examining their monuments, we meet with certain figns of their having been acquainted with fome fecrets, to which we, moderns, are utter ftrangers. We are, no doubt, very rich without them; but that is no reason why

we should not endeavour to recover them; and, instead of trufting to chance, employ both obfervation and experiment for that purpose.

Of this, one of the most important branches of architecture is a ftriking proof. Though the genius of our modern mafters in that

art formed by the ftudy of those monuments left us by the ancients, has fucceeded fo far as to produce édifices capable of vying with their patterns, it may be fairly faid, that we are at a great remove from the Greeks and Romans, with refpect to the running up of buildings with the degree of rapidity they used to do; and yet bestowing on them that degree of folidity, which feems to defy time itself; and all this, with almost every kind of materials they could lay their hands upon.

It is, no doubt, an easy matter to raise lasting edifices by piling one upon another enormous blocks

Be

veral countries, of very confiderable extent, in which no fuch materials are to be had; and there are others, in which, though these materials abound, they are of too loose a texture to refift, for many years, the viciffitudes of the weather. fides, this way of going to work is monftroufly expenfive. It is what very few fimple fubjects can pretend to; and, accordingly, few of the houses built by them are of any duration. Nay, ftates themselves are now often obliged to renounce the execution of the most useful works, on account of the enormous expence attending them in the modern method.

But

But the Romans, it is plain, generally employed, efpecially in thofe public works in which ufefulness was more to be attended to than ornament, a far lefs expenfive mode of construction. The principal part of fuch works, if not the whole of them, ufually confifted of materials of a very fmall bulk, but kept together by a mortar or cement of a moft binding quality. What a fine method! One can hardly fum up all the advantages attending it. In it, they could make ufe of every kind of stuff already existing on the furface of the earth, and even ftones, every where almost to be met with in the beds of rivers and torrents, though worn round, nay, and polifhed, by their conftant attrition against each other, or other bodies*. They had no occafion for the unweildy apparatus of heavy carriages to bring their materials to the spot, or cumbrous engines to raise them; confequently, they loft neither time nor labour in the execution of thofe tedious operations; all went directly to the forwarding of the work itfelf, which, of course, muft have fhot up with uncommon rapidity. How, otherwife, could they have executed, even with their numerous armies, thofe immenfe piles; those aqueducts of feveral leagues in length, and fometimes rifing to the level of mountains; and all this often, merely to fupply fome middling town with water, not only for the neceffary, though common, purposes of life; but even for

thofe of luxury and magnificence; fuch as baths, fountains, &c.

Thefe confiderations did not efcape Monfieur Loriot, fo defervedly celebrated for his many very useful mechanical discoveries and inventions; and, it was in confequence of them he made these inquiries and researches; the fruits of which I am now going to communicate to the public. Ever taken up withthe thoughts of ferving his country and mankind, by cultivating and improving the fine and the useful arts, the great number of those vaft remains of Roman grandeur, fcattered over our fouthern provinces, could not fail of fuggefting to him, that the folidity, fo confpicuous in them, could not be owing to any fecret confined to any one portion of mankind, nor to any merely local advantages, nor to any peculiar excellency in the quality of the materials; but that it must be the refult of fome common and easy method, within the reach of every man in the world of workmen employed in thefe erections. But, perhaps, we had better follow the example of Monfieur Loriot and, like him, particularly analyse these ftupendous monuments, and thence regularly deduce the manner in which, it may be prefumed, the Romans conftructed them.

:

Most of these monuments exhibit nothing but enormous maffes in point of thickness and height, the heart of which, but juft faced with an almoft fuperficial coating, evi

dently

dently confifts of nothing but pebbles and other small ftones, thrown together at random, and bound by a kind of mortar, which appears to have been thin enough to penetrate the smallest interftices, and fo form a folid whole with these materials, which ever kind was firft laid to receive the other when poured into it. It is enough, therefore, to confider these ruins, with the smallest degree of attention, to be convinced that all the fecret of this mode of construction confifted in the method of preparing and ufing this ftrange kind of mortar; a mortar not liable to any decay; bidding defiance equally to the perpetual erofions of time, and heaviest ftrokes of the hammer and pickaxe. At least, when any little ftone, and it must be a round one, gives way to them, the mould of cement left by it is found equally hard with the compleatest petrifi

cation.

How different, then, must this ancient mortar be from the very beft of our modern! The latter, one would imagine, never dries perfectly, but to fall to duft again at the leaft touch. Of this the remarkable crumbling away of our moft recent buildings is an evident proof.

Another of the extraordinary qualities of this Roman cement, is, its being impenetrable to water. This is not a mere conjecture. It is a fact, which the aqueducts of theirs, ftill in being, leave not the leaft room to doubt of; for, in these works, they never employed either clay, mattich, or any other refinous fubftance, to prevent the waters making their way through them.

The areas of these canals, refting fometimes on the ground,

fometimes on a wall, and sometimes on arches, built for the purpose, as well as their roof and fides, confifted of the fame kind of small ftones, bound together by this extraordinary cement; with this dif ference, that the infide surface was compofed of finer and fmaller ingredients, which, at the fame time that it does not look any thing like a coating made at fecond hand, and of courfe capable of being fcaled off, carries evident marks of its being the refult of a peculiar ope ration, which it may not be impoffible to imitate by carefully attending to the observations that will occur in the course of this Effay.

Thus, then, it plainly appears, that these works were carried on by means of cafsoons. The trenches made for the foundation formed, of themselves, the lowest tire; and, furely, nothing could be eafier than to fill thefe with the materials ready prepared for that purpofe; tho' the Romans, no doubt, did it with their largest and heaviest ftones. After bringing the work to the furface, they had recourfe to planks made to fit into each other, fucceffively extending them in length and in height, and binding the oppofite ones at fuch a distance from each other, as to form the thickness. of the wall; and, withal, with sufficient ftrength not to deviate ever fo little, from the perpendicular, on either fide.

It was thus that they formed, as it were in a mould, these enormously maffy walls, compofed, as we have already feen, of every fpecies of pebbles, and other fmall ftones, which our modern architects know not what to do with for want of a mortar qualified to conftitute with them one folid compact body.

We

We may eafily conceive, at what a great rate, even a fmall number of hands, if well fupplied with materials, must have been able, by this means, to push on any work in the building way. For this purpofe, nothing more was requifite than to have in readiness a fufficient number of troughs full of the proper mortar; throw, at random, into the caffoons, the pebbles, and other fmall tones, and then faturate the latter with the former; all which might be perfectly well done, by the fmallest degree of attention to get as much ftones as poffible into the caffoon; and then make the mortar fill up all the interftices between them; and, with regard to vaulting and arching, they had their centers, as well as the moderns. When they had an aqueduct to build, then, as the interior furfaces of its channel required a coating of that peculiar cement, which is till obfervable in them to a certain thickness, and which we have already taken notice of, they began by laying it on the planks of the interior cafing and the centers, previous to the throwing in of the coarfer materials; and thus formed a cruft, which effectually kept the water from any ftones of a fpungy nature, that would otherwise have imbibed it.

Without this method of cafing, they would never have been able to construct, either walls of fo prodigious a thickness, or channels of fo furprising a thinnefs. In a word, the effect of this cement must have been very quick, to coalefce and fet as readily as our gypfes and plafters, and directly refift the preffure of the other materials laid upon it. fact, the leaft fhrinking or fwelling must have proved fatal to works of

In

this kind, not one of whose parts, perhaps, yielded a folid and horizontal bafis to any other.

This fixednefs and perfeverance within the fame volume constitute another important quality, which the flenderest observation must convince us the Roman cement is endued with; and being the last as yet discovered, we may proceed to fum up all the excellencies peculiar to this extraordinary compofition.

In the first place, then, this ce ment, from a liquid, turned very quickly to a folid ftate, and har dened with time as plafter does.

Secondly, it acquired a furprising degree of tenacity, and laid fuch hold of the fmallest ftones it came in contact with, as searce to bear being parted from them.

Thirdly, it was impenetrable to

water.

Fourthly, it continued always of the fame volume or bulk, without either fwelling or fhrinking.

One would imagine, that so many extraordinary qualities fhould have fecured this compofition from the effects of violence and time, and kept the fecret of it alive to the latest posterity. Yet, it may be fafely affirmed, that this valuable fecret has been loft to all intents and purposes; and that, notwithftanding the continued and hearty fighs and researches of all Europe, nothing like it, till now, has been discovered by the moderns. For if, in fome parts, the buildings are more folid than others, it is merely owing to the extraordinary goodnefs of the lime, fand, and other materials employed in them.

[The Editor, after combating one paffage in Pliny, and another in Vitruvius, which feemed to militate with our ingenious artist's

opinion