flakes on the furface. In winter, when the falls of snow begin, the earth is formed into fmall refervoirs, by railing it into banks about fix inches high. These being filled with fnow, and hot water from the lake poured upon it, the borax, after the water has partly foaked away, and partly evaporated, remains on the bottom, in a cake sometimes half an inch thick. It is faid that fnow is indifpenfable; that the earth is at that feason richest in falt; that after the borax has been thus extracted, no more can be obtained from the fame spot, till the fnow has fallen and dif folved three or four times, after which the faline efflorescence reappears, and the earth is again fit for the operation. Father Rovato mentions different valleys, at diftances of feveral days journies, in which the elixation of the borax from the earth, as well as its formation, is effected wholly by nature: the rain water is collected into pools, and after fome time the workmen wade into thefe pools, where, feeling a kind of pavement under their feet, they accordingly dig up the borax, which lies in a thicker or thinner cake, according to the depth of the water. Sur les Gas Hepatiques: par Monfieur Haffenfratz, This article relates fome experiments for afcertaining the compofition of inflammable hepatic air, or the air which is difengaged in the precipitation of solution of hepar fulphuris by ni❤ trous acid. That it contains actual fulphur has already been discovered; and M. Haffenfratz fhews, fynthetically, that its other ingredient is inflammable air; for fimple inflammable air, paffed through fulphur in fufion, becomes fulphurous, perfectly fimilar to the hepatic; and other airs, by the fame treatment, acquire a like fulphurous impregnation. An Account of an Experiment on Heat. By George Fordyce, M. D. F. R. S The experiment is this: A circular piece of iron plate, and another of pafteboard, exactly equal in dimenfions, being placed each as a diaphragm in a pafteboard tube, and expofed equally to the fun, fo as to receive equal quantities of his rays, with the fides next the fun coated equally with black paint, to prevent the rays from reaching to the pieces themfelves; the tubes clofed at bottom, placed within wider tubes, and the spaces between filled with eider down, to prevent the diffipation of heat; and a thermometer introduced in each by a lateral tube below the diaphragm ;-the greateft heat was produced in the apparatus with the iron diaphragm. In the first two or three minutes, the pafteboard became hotteft; but when the iron began to grow warm, it heated fafter, and became actually hotter than the pafteboard, and continued to do fo after the pafteboard had ceafed to receive any any additional heat. After they were both reduced to the fame temperature, the iron was longeft in cooling. This experiment was made with a view to chemical opera❤ tions. The Doctor obferves, that if the fame quantity of fuel being burat, will produce always the fame quantity of heat, our whole attention will be, to take care that no part of the heat fhall be loft; but that if burning it under one fet of circum. Rances will produce more heat than burning it in other circumftances, or if burning it will produce a great heat in one place, which cannot be carried to another place, but will be again an nihilated, a very different attention must be paid. He was led to this train of thinking by fome experiments in a reverberatory furnace, in which he could eafily produce the required degree of heat with coal," but could not by any means with charcoal or coke, though he heightened the chimney, and infulated the furnace, so that, after twenty-four hours ftrongeft fire, it did not feel in the least warm on the outfide in the fire-place the heat was fufficient to melt malleable iron, but in the laboratory, or horizontal part of the chimney, it was trifling. We do not clearly perceive how the experiment applies to this fubject, nor what the difficulty is which the Author means to elucidate. We fuppofe both operative and philofophi'cal chemifts know, that with fuel of the fame fpecies, the intensity of the heat is in proportion to the quantity of fuel confumed in a given space and time; that when the fuel is of the non-flaming kind, the intense heat is about the middle of the fire; but that with flaming fuel, it is in the tract of the flame, and greatest towards its extremity; and that fo long as the flame continues, the heat among the coals is comparatively inconfiderable. Did the Doctor expect that the intenfe heat of a non-flaming fire, however confined by the fides of a furnace, could be tranfported to a cavity at a distance, so as to act there with the fame force as in the fire itself ? Some Obfervations on ancient Inks; with a Propofal for a new Method of re.overing the Legibility of decayed Writings. By Charles Blagden, M. D. Sec. R. S. & F. Á. S. A queftion had arilen, whether the inks in ufe eight or ten centuries ago, and which are often found to have preferved their colour remarkably well, were made of different materials from thofe employed in later times, many of which are already become fo pale as fcarcely to be legible. Experiments on ancient writings themselves, with the chemical re agents, afford the fureft means of determining this queftion; and Dr. Blagden, having been furnished with old parchments for that purpole, found the ink to confift, like ours, of iron and aftringeut matter. The minuteft quantity of iron, when diffolved by an acid, is discover able able by ftriking a blue with Pruffian lixivium; and when the letters on those parchments were touched with acid, the application of Pruffian lixivium turned them to an intense blue. This experiment, while it fully afcertains the basis of the an cient inks, points out a new method of reftoring them, when decayed, to a legible and ftrong colour. The only inconvenience is, that the iron being brought into a ftate of folution, is apt to spread beyond the traces of the letters, fo that the operator muft be very cautious in the application of the two liquids: the fafeft way is to apply the Pruffian liquor firft, and then the acid. The reviewer of this article had been turning his thoughts to the fame object, but on a different fide; not the restoring of writings when decayed, but the prevention of their decay. The late Dr. Lewis has fhewn, in his Commerce of Arts, that the black matter in ink is a chemical combination of iron with a peculiar aftringent fubftance, which has fince been diftinguished by the name of aftringent or gall acid, as Pruffian blue is a combination of it with the fubftance called Pruffian acid; but that the aftringent fubftance is infinitely more perishable than the Pruffian, the blackness being deftroyed by exposure for a few weeks to the open air and fun, and only the yellowish iron calx remaining, fo pale as hardly to be vifible. He therefore propofed not only increafing the quantity of this perishable ingredient in the ink, as far as was confiftent with fufficient colour on first writing, but likewife impregnating the paper or parchment with the fame material. This would undoubtedly be of great advantage, but it is attended with fome inconveniences, particularly an unfightly yellow or brown colour, communicated by the galls when the impregnation is ftrong enough to prove effectual. We therefore attempted firft to introduce the Pruffian acid along with the aftringent, in the compofition of ink, with the hopes both of improving the colour, and continuing a blue after the decay of the black. But finding the blue too much disposed to precipitate from the fluid, we wafhed papers and parchments with the Pruffian acid, which does not in the leaft injure them in whiteness, or any other refpect. By writing with common ink on the materials fo prepared, a ground of Pruffian blue is formed under every ftroke, and remains ftrong after the black has been deftroyed by the weather, or difcharged by acids. In this method the ink will bear a little increase of the vitriol, and thus have the further advantage of being deeper coloured on firft writing; for a furplus of vitriol has that effect in common ink, though it haftens very greatly the fubfequent decay. We hope these hints may deferve the notice of those who are interested in the durability of writings. This volume concludes with a numerous account of books prefented to the Society, from November 1786 to July 1787, with the names of the donors; and an Index to the whole, &c. as usual. ART. III. The Hiftory of Limerick, Ecclefiaftical, Civil, and Military, from the earlieft Records to the Year 1787. Illuftrated by 15 Engravings. To which are added, the Charter of Limerick, and an Effay on Castle Connel Spa, on Water in general, and Cold Bathing. By J. Ferrar, Citizen of Limerick. 8vo. 6s. Boards. Lane, in London. 1787. Judicious felection of facts, from authentic records, conftitutes the principal labour (as well as merit) of hiftorical compilements. It is a work of great difficulty, and requires confiderable powers of difcrimination and judgment to adopt or reject the feveral particulars which diligent enquiries, and the attentive perufal of written evidence, have furnished. Mr. Ferrar feems to have beftowed great pains in procuring information; and if his arrangement does not appear to be fo advantageous to the reader as it might have been, he is, neverthelefs, entitled to our approbation on account of his industry, candour, and liberality of fentiment. The work is divided into fix parts, of which the first and second treat of the ancient and prefent ftate of the city; with the moft remarkable events: among others, the memorable fiege of Limerick, when that city withftood the power of William III. The third and fourth defcribe the churches, religious houses, public buildings, and charities. The fifth contains lifts of the provofts, mayors, &c. the charter of the corporation, articles of the capitulation of Limerick, and a lift of men of learning and genius which the county has produced. The fixth and laft part defcribes the county of Limerick, with an account of the ancient families, &c. and a lift of the reprefentatives in parliament, and high fheriffs, fince the year 1770, with a lift of fairs, &c. The fixth part, though chiefly confined to the county of Limerick, contains fome particulars relative to Ireland in general. Mr. Ferrar fays, there are in Ireland 11,042,642 acres, and 2293 parishes. He gives a table of the number of acres in each county, of the average rental per acre, and feveral other particulars relative to the commerce, agriculture, and internal state of the kingdom. Whence the Author has felected his information on these fubjects we are not informed. Mr. Ferrar has added an Effay on the Virtues of Cafle Connel Spa; or Water in general, and Cold Bathing. From the account which he gives of this Spa, it appears to be a chalybeate; but as he hath not added a chemical analysis, we cannot judge judge of its ftrength. The practical directions for drinking the water, and for bathing, are compiled chiefly from Dr. Rutty and Dr. Short; and he could not have reforted to better authorities. To the inhabitants and natives of Limerick the work will doubtless be acceptable; it will alfo be ferviceable in fome inftances to the antiquary and hiftorian. The short biographical articles, at the end of the fifth part, are valuable to the biographer; and though it contains but few lives, yet they will add to the general ftock, and serve as materials for a Biographia Hiber nica. ART. IV. Bibliotheca Topographica Britannica. 4to. Nichols. 1787. N our Review for laft month, p. 99, we gave an account of Numbers 37, 38, and 39, of this valuable work; and we have now before us the 40th, 41ft, and 42d Numbers; the for mer of which contains the hiftory and antiquities of the town, college, and caftle of Fatheringay, in the county of Northampton. Price 4 s. The caftle at this place feems to have been firft erected about the year 1084. By an inquifition made in the reign of Edward III. when it defcended to William de Bohun, Earl of Northampton, it appears to have been greatly enlarged, improved, and well accommodated, according to the manner and tafte of the times. Its ftate in the reign of Henry VIII. when it was part of the dower of Queen Catherine, is briefly described by Le land, who was much pleafed with the beauty of the circumjacent country. The college here, together with the church, was erected on the ground where had formerly been a convent for nuns, by Edward Duke of York, in 1412, and fome following years. This college appears to have been no more than a religious foundation, for the fupport of a mafter, twelve chaplains, eight clerks, and thirteen choristers, whofe bufinefs it was to pray for the fouls of all the royal family, during their lives, and after their decease, &c. But we obferve, that after the Reformation, Laurence Saunders, M. A. of King's College, Cambridge, is ftyled divinity lecturer at this place, and was afterwards, in the reign of Queen Mary, burnt at Coventry, on account of his religious principles. Several circumstances of an amufing kind are related concerning Fotheringay; but that which renders it chiefly memorable in the annals of English hiftory, is the long confinement and execution of Mary Queen of Scots. This tragical event furnifhes many pages of the prefent article. The editor draws his materials principally from the Harleian Mifcellany, the Cotton Library, and Gunton's Peterborough. The funeral of the un 7 fortunate |