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little difference in the memoir tranfmitted to Dr. Priestley. from that which was published.

Iron melted in pure air, by a burning lens, was found to absorb the air almost entirely; the remainder was fixed air, and the iron was reduced to a calx; it increased in weight in proportion to the air abforbed. On reducing it, the increased weight difappeared, and the inflammable air loft was exactly the quantity fufficient to faturate the pure air which had originally disappeared; that is, it was enough to have completely exploded together. The additional weight which the iron had loft, however, appeared in the form of water, that covered the fides of the veffel in which the experiment was made. The remaining`air was inflammable. The experiment succeeded alfo in Dr. Priestley's hands with copper and mercury, though M. Lavoifier's experiment with the tube of copper failed. We muft, therefore, wait for farther information on this fubject.

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In other experiments, Dr. Priestley found that water was effential to the production of inflammable air. He was not aware that iron and charcoal, when intenfely hot, had so strong an attraction for water, that they would attract it in the midst of the hotteft fire, and through the pores of a retort? He repeated his experiments, and faw that both fubftances only produced this air in confequence of water being accidentally prefent.

Though Dr. Priestley agrees with M. Lavoifier in the refult of his experiments, he differs in the conclufion drawn from them. He ftill contends for the existence of phlogifton in inflammable air; though with both English and French chemifts he seems to allow, that water is produced by the union of these kinds of air. In his experiments for this purpofe, which were made with steam tranfmitted through charcoal, the inflammable air was united with fixed air, and the latter was often fo accurately combined with the former, that it appeared only after decompofition. It feemed probable too, from the quantities expended, compared with the air procured, that it came rather from the other materials than the water. It was fomewhat better eftablished by the experiments with iron. We fhall add Dr. Priestley's theory of the changes produced by these experiments, on the fuppofition that phlogifton really exifts.

Since iron gains the fame addition of weight by melting in dephlogisticated air, and alfo by the addition of water when red-hot, and becomes, in all refpects, the fame fubftance, it is evident, that this air or water, as exifting in the iron, is the very fame thing; and this can hardly be explained but upon the fuppofition that water confists of two kinds of air, viz. in

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flammable and dephlogifticated. I fhall endeavour to explain these proceffes in the following manner.

When iron is melted in dephlogisticated air, we may fuppofe that, though part of its phlogifton escapes, to enter into the compofition of the fmall quantity of fixed air which is then procured, yet enough remains to form water with the addition of dephlogisticated air which it has imbibed, fo that this calx of iron confifts of the intimate union of the pure earth of iron and of water; and, therefore, when the fame calx, thus faturated with water, is expofed to heat in inflammable air, this air enters into it, destroys the attraction between the water and she earth, and revives the iron, while the water is expelled in its proper form.'

Some other curious experiments are added, which feem to fupport the English theory, in oppofition to that of M. Lavoifier; but we cannot particularly relate them. Dr. Prieftley concludes this curious paper with a hint that fome important difcoveries are nearly within our reach.' May this prophecy foon be realized!

The New Difpenfatory. By William Lewis, M. B. F. R. S. The Fifth Edition, carefully revised and corrected. 8vo. 75. 6d. Nourfe.

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The Edinburgh New Difpenfatory, containing Elements of Phar c. the two latter Parts comprehending the Preparations and Compofitions of the laft London and Edinburgh Pharmacopeias; being an Attempt to collect and apply the later Difcoveries to the Difpenfatory, published by Dr. Lewis. By Gentlemen of the Faculty at Edinburgh. 8vo. 7s. 6d. Elliot, Edinburgh Robinfons, London. $

THE appearance of a new edition of Dr. Lewis's Difpenfatory, at the fame time with an attempt to improve and amend it, has led us to compare these new publications with that on which they are formed. It would be useless and im pertinent to enlarge on the original plan; for it is our present bufinefs only to examine the improvements: indeed the medi cal world has already decided on the merits of the former editions; and Dr. Lewis has gained, by his work, a very exten five reputation.

In the interval between the appearance of the fecond edi tion, for that was greatly improved by the author himself, and the prefent time, chemistry has almost become a new science; many articles have been added to the materia medica; feveral foreign Difpenfatories have appeared with great applause; and the Edinburgh college have published two very improved edi

tions of their own. We may take this opportunity of informing phyficians, that there is reason to expect a new one, from the college of this kingdom. It is indeed to be regretted, that pharmacy has not shared the same attention as chemistry; nor has it been examined with the indulgent fondness which has diftinguished the other branches of the fcience; yet we certainly owe to the labours of chemists a more intimate acquaintance with the nature of metals, and a more exact mode of preparing metallic remedies: we more clearly understand the nature of vegetable and animal substances; and, in a few inftances, have enlarged our knowledge of their respective menftrua. Many new articles of the materia medica are indeed already almoft forgotten, and fome cannot yet be procured; but, in a fyftem of this kind, it is neceffary that they should be mentioned, and the little information which we can obtain fhould be communicated.-From the foreign Difpenfatories much knowledge can be procured. The best of these, the Wurtenburg Pharmacopæia of 1771, whofe authority is very extenfive through Germany; the Ruffian, the new Brunf wick, and the late Swedish Difpenfatories, might have contributed ufeful affiftance to the prefent plan. We are forry to observe that our editors have overlooked, or not been able to procure them. The omiffion perhaps is rather to be lamented than cenfured.

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The conduct of thefe different improvers, in the latter parts of the work, is nearly the fame. The alterations in the last, are those only of the Edinburgh Dispensatory; and the former profeffes to corre the formula' from the fame work. But, while the promises of the first feem to have been punctually, thofe of the laft have been carelessly, executed. The new formulæ are not added, and few marks of correction occur.

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In the Materia Medica, (we choose a retrogade order, fincé thefe works diverge from each other in this direction), the additions to each are numerous; and the new articles are nearly the fame; the fources from which they are transcribed are also not very different. In the London edition, however, the former remain unchanged; in that of Edinburgh, additions are freely interfperfed: tables of mercurial and antimonial preparations are fubjoined, as well as fome articles which are not found in the other. Thefe are the lactuca', one spe cies of which, the virofa, has been recommended in dropfies;

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lichen islandicus,' nux vomica,' &c. On the contrary, neither the quercus marina' (fea wrack), or the viola tricolor,' which have shared the attention of the London editor, are mentioned; and, though the title of the falix is found,

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its

its real or imputed virtues are omitted. In the conduct of the articles, the botanical defcriptions are very generally fuller in the London edition; though in each, the Linnæan names are mentioned in this too they are longer, fometimes on account of the more diffuse style, sometimes occafioned by additional information. In this laft refpect, the articles of columba, colchicum, dolichos pruriens, oenanthe crocata,' and fome others, are more valuable: thofe on the pulfatilla,' the • quaffia,' and the ricinus,' are, we think, less fatisfactory, though farther extended.

The value of the Edinburgh edition is greatly increased by the chemical and pharmaceutical efflays in the introduction, extracted from Dr. Webster's Syllabus: in this view it is unrivalled. The additions to Dr. Lewis are very numerous, and highly important. The chemical part is new, accurate, and fatisfactory. One or two typographical errors of fome confequence have, however, been overlooked; and two paffages are marked with inverted commas, as new, though really co❤ pied from Lewis. These are trivial imperfections. The de fcriptions of the new furnaces, and the new table of elective attractions are very valuable; but they would require a plate to enable us to defcribe them.

From the new articles of the materia medica we can felect no fpecimen; for they are very generally compiled from works pretty well known, and, except in one or two inftances, are not very important: it would not have been difficult to have rendered them more ufeful. We ought, however, to add, that, though on old fubjects, the account of the bark and opium, in the Edinburgh edition, are new. The botanical discoveries relating to the firft, and the additional knowledge we have acquired of the laft, fince we have been lefs afraid of it, feem to require a new compilation. We must be allowed to wifh, that the materia medica, in both works, had been fuller in the number of articles; and that the editors had not been confined by the limits of either college.

We shall select no fpecimen even from the part which we have faid is almost wholly new; fince its great merit confifts in the very clear concife manner, in which fubjects, well known to the chemift, are detailed; and we have little room for compilations, even of the greatest merit.-On the whole, after having made a careful comparison of these two works, we must recommend the Edinburgh edition, as the most useful companion and inftructor. We cannot give it a higher character than to obferve, that, in the present ftate of fcience, it is, what the original work was, at the time of its first appear

ance.

Structure

A Key to the Mystery of the Revelation: whereby all its dark Meanings, being reduced to one regular System, are easily accounted for, and explained. 8vo. 45. in Boards. Goldsmith.

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No object of theological difquifition feems to have been more fertile of keys, comments, and expofitions, than the Revelation of St. John. And indeed the mysterious nature of its contents, and those delivered in a ftyle of the utmoft folemnity and grandeur, afford a very natural and proper fubject of enquiry to thofe divines, who have learning and leifure to pursue it. But whoever fits down with an intention of explaining the whole of this ænigmatical book, will probably mifcarry in many points. Sir Ifaac Newton fays, that among the interpreters of the laft age, there is scarce one of note, who hath not made fome discovery worth knowing, but that our greatest obligations are owing to three particularly, Mede, Vitringa, and Daubuz.' But neither fir Ifaac, nor, we fuppofe, any rational divine, has adopted all their folutions or conjectures. The learned bishop of Bristol, whose Illustrations of the Apocalypfe deserve no mean fhare of credit among thofe of the prefent times, obferves that to explain it perfectly, is not the work of one man, or of one age; and probably that it will never all be clearly underftood, till it is all fulfilled.' Whoever undertakes to develope its mysteries with wisdom, fobriety, and reverence, will probably contij bute fome new light for our guidance, and merit the thanks of the ferious part of mankind.

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The anonymous author of the prefent publication tells us, in his introduction, that he flatters himself he is poffeffed of the happy clue, which, he adds, was many years ago accidentally discovered to a friend. It is no more, he informs us, than the fimple hint of confidering these myfteries as a regular feries of ecclefiaftical events, from the beginning to the end of time, but yet variously expreffed, agreeably to the feven parts into which hey feem naturally to be divided.' The author gives us to understand, that he has found, from many years experience, the great efficacy of this Key, or manner of explanation now offered to the public; and that it is aftonishing to fee fuch a heap of feemingly wild and jarring matters, fo easily yielding themselves to order and arrangement, by fo fimple a means. We were led, by this declaration, to expect more fatisfaction than we can confefs ourselves to have found. The fcheme itfelf is, however, far from wanting ingenuity; but its fimpli city, which the author probably thinks its first recommenda tion, we are inclined to regard as its principal defect. A key, too fimply constructed, cannot be applied with fuccefs to the VOL. LXI. Feb. 1786. H wards

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