A strong effervefcence with much heat took place. The globule ' in a few minutes had enlarged to five times its former dimen'fions, and had the appearance of an amalgam of zinc; and me'tallic chryftallizations fhot from it as a centre, round the body ' of the falt. They had an arborescent appearance; often became 'coloured at their points of contact with the muriate; and, when the connexion was broken, rapidly disappeared, emitting ammo'niacal fumes, and reproducing quickfilver. Carbonate of ammonia gave the fame refult; only that a manifeft decompofition of the acid, and production of carbonaceous matter, accompanies the other phenomena in this cafe. The bafes of the alkalis and earths, united with mercury, and exhibited in this state to ammonia, fupplied the place of electricity, and formed an amalgam of the bafes of ammonia and mercury. A little of the bafis here used for the purpose of deoxygenating the ammonia, adhered to it in the amalgam; but, independently of this confideration, our author feems to think, that the experiment in question unites more of the ammoniacal bafis to mercury, than the procefs of deoxygenation by clectricity. He does not mention, though we muft prefume, that, in this ingenious and beautiful experiment, the fixed alkalis or earths are reproduced.

The fingular amalgam difcovered by the Swedish chemifts, may thus be obtained with great eafe, either by the agency of electricity, or by double elective affinity. But our author preferred the former method, because it is not attended with the admixture of any third fubftance, giving the amalgam compofed folely of mercury, and the bafes of ammonia. Having procured a fufficient quantity of it in this way, he examined it by various fimple and fatisfactory trials. Its principal properties are the following. At 70° or 80° this body has the confiftence of butter ;-at the freezing point it hardens and chryftallizes it is not quite three times heavier than water. In water, it abforbs oxygen, caufing hydrogen gas to be evolved. In air, it likewife abforbs oxygen; and, in both cafes, ammonia and quickfilver are reproduced. In fulphuric acid, it becomes coated with fulphate of ammonia and fulphur. Sixty grains of mercury are amalgamated by part of a grain of the compound bafis, or of the weight of the mercury. The very fmall proportion in which the bafis thus unites with mercury, oppofes an obftacle to the feparation of the two bodies, and the exhibition of the bafis of ammonia, which all Mr Davy's induftry and fkill have not been able to furmount: for, fo very minute a portion of oxygen is fufficient to regenerate the ammonia, and fo greedily does the bafis attract oxygen, wherever it may be found, that no manipulation has hitherto been attempted, in which, either by means of moisture, air, or fome other body

I

containing

containing oxygen, a reproduction of the ammonia, did not take place, notwithstanding every precaution. We refer our readers to the paper itself, for an interefting narrative of the trials made. by the ingenious and perfevering author, to attain the highly important object in queftion. The difficulties which frustrated his endeavours, are all refolvable into the general statement just now given; and we have great hopes that they will hereafter be overcome, either by this indefatigable inquirer himself, or by fome other chemists, whom his highly commendable publication of his experiments, in their prefent ftate, may lead to happier results.

Mr Davy concludes his valuable paper with fome general fpeculations concerning the theory of alkaline and earthy bodies, as elucidated by the difcoveries which we have just now, and on two former occafions, confidered. His obfervations are always ingenious; and whatever comes from fo great a difcoverer, one fo ftrict in his experimental investigations, and fo fuccefsful in generalizing them, ought to be received with fingular refpect. Nevertheless, we shall not follow him through the whole of his queries and reflections, highly ufeful as they are likely to prove. We fhall only state what we conceive to be the legitimate inferences from his experiments, and then notice a few of his most prominent obfervations. It is clearly proved, that the fixed alkalis, and the alkaline earths, are metallic oxides; and the proportion of their bafes are nearly as well afcertained as thofe of feveral metals known for ages to philofophers, and in common life. That alumine, zercone, glucine, and filex, are alfo metallic oxides, feems highly probable; but their decompofition has not yet been fo completely effected as to render this point altogether certain; and, refpecting the metals which feem to conftitute their bafes, we can scarcely be faid to know any thing with precifion. It is demonftrated, that ammonia is a compound of oxygen, with hydrogen and nitrogen; and that when the oxygen is removed, the hydrogen and nitrogen are capable of entering into a true chemical union with mercury, forming a substance in all respects fimilar to the amalgams of that body with other metals. It is highly probable, that the hydrogen and nitrogen are united together as a chemical compound, which thus unites with mercury; and that the fame compound unites with oxygen to form ammonia. The appearance of amalgamation, as well as the analogy of the other alkaline bodies, leads us to suspect that this compound basis is truly of a metallic nature, and that the volatile, like the fixed alkalis and the alkaline earths, is a metallic oxide; but this bafis has not yet been feparately exhibited. Such, in general, is the state of our knowledge upon the conftitution of the alkalis and earths, as extended by the late wonderful difcoveries; and fuch is the line to

be

be drawn between what we have strictly learnt as phyfical truths, and what we have been taught to conjecture upon evidence of a lower nature than that of legitimate induction.

The last of these wonders, the conftitution of ammonia, gives rife to various hypothefes. To account for the phenomena of amalgamation with mercury and reproduction of the alkali, three different theories have been stated. Mr Davy himself seems to think it poffible, that hydrogen and nitrogen are both metals, aëriform at common temperatures, as zinc and mercury are when ignited. Mr Berzelius fuggefts, that they may be fimple bodies, not metallic, but forming a metal when united, without oxygen; and an alkali, when united and oxygenated. Mr Cavendish has fubmitted a third conjecture, that these gafes, in their common form, may be oxides, which, when further oxigenated, become metallic. Of these hypothefes, or rather queries, (for it would be unfair to the diftinguished and truly philosophical authors of them, if we did not remind our readers that they have only been thrown out as hints for future investigation), we should prefer the laft; at least, in point of beauty and fimplicity, it feems to have fome advantage. But the feason, we truft, is not far diftant, when we fhall be enabled to try their comparative merits by another and a higher crite-rion.

ry.

The fingular facts which abound in the decompofition of ammonia, appear to ftrike Mr Davy as capable of leading to some degree of fcepticism refpecting the phlogistic and antiphlogistic theories; but he clearly shows that they leave the latter in a much better ftate than the former. He thinks them not eafily reconciled to either; but with lefs difficulty to the antiphlogistic theo'If,' If, fays he, we affume the phlogiftic hypothefis, then we muft affume, that nitrogene, by combining with one fourth of its weight of hydrogene, can form an alkali, and, by combining with one twelfth more, can become metallic. If we reafon on the antiphlogistic hypothefis, we must affert, that though mitrogene has a weaker affinity for oxygene than hydrogene (has),. yet a compound of hydrogene and nitrogene is capable of de-. compofing water. And he proceeds to fhow that the latter difficulty is the leffer one; and though he thinks it cannot be wholly removed, it may yet be diminished by chemical analogies; for example, by the fuperior inflammability of certain compounds, and the greater oxidability of alloys. We confefs, that, to us, this difficulty feems by no means greater than feveral others not alluded to by Mr Davy; and we advert more particularly to the cafe of nitrous gas. Nitrogene, by combining with a certain proportion of oxygene, acquires fo great an attraction for more oxygene, that it takes it from nitrogene. Here is the very difficulty

ftated

ftated by our author, as involved in the antiphlogiftic explanation of the decompofition of ammonia; with this difference, that it is rather more hard to conceive how nitrogene with oxygene fhould take oxygene from nitrogene, than it is to conceive how nitrogene with hydrogene should take oxygene from hydrogene. The difficulty, we prefume, is generally explained by faying, that the various degrees of latent heat contained in the fame body vary its elective affinities. In fact, this difficulty belongs to a clafs of phenomena by no means of fmall extent. Carbon, for example, takes oxygen from phosphorus in reducing phosphoric acid; and phosphorus decomposes carbonic acid. In like manner, fulphur reduces the oxides of feveral metals, which, in their reguline ftate, decompofe fulphuric acid. We are far from saying that these phenomena are unattended with difficulty, on whichever theory we attempt to explain them. We would only fuggeft, that the discovery of the Swedish chemifts, and its extension by Mr Davy, has added no new difficulty to the lift, and offers no new anomaly to the modern theory.

Befides the experiments which form the body of the paper now before us, there are various important facts introduced incidentally. We have already noticed the decompofition of carbonic acid by the electric agency. There are fome very interesting experiments on the conftitution of the muriatic acid, which we truft may hereafter lead to a full folution of that problem. A long and curious note is also given upon the discovery of Meffrs Gay, Lufac and Thenard, that the alkalis may be decompofed by the action of iron in a state of ignition ;-a new example, by the way, of the difficulty above mentioned; for potaflium and fodium eafily reduce the oxides of iron. But we should give a very unfatisfactory account of this curious matter, were we to take it at fecond hand. We hope to be able, in our next Number, to lay before our readers an abstract of the history of the discovery from the authors themselves.

ART. XI. Memoirs of John Lord de Joinville, Grand Seneschal of Champagne. Translated by Thomas Johnes, Esq. At the Hafod Press. 1807.

T HE Memoirs of Joinville have always held a high rank among writings of that class. They are indeed entitled to particular notice, as the earliest specimen of history in a modern language; except Ville-Hardouin, which is not a very common book; and the French original of William de Nangis, which is

still less known. From the dissolution of the Roman empire to the 13th century, the charge of perpetuating past transactions fell to the share of narrow and bigoted monks, who treat the affairs of mankind only by the way; and treat, at large, of nothing but their own spiritual squabbles, or the miracles of their saints. Those who praise the natural simplicity of antient writers, and regret their lively portraiture of manners, are very partially acquainted with the great mass of chroniclers. No man has ever turned over, with weary patience, the folio pages of the Benedictine collection of French historians-of Muratori's Scriptores Rerum Italicarum-of Reibomius, Frehorus, or Urstisiuswithout acknowledging the worthlessness, generally speaking, of these annalists, in any other view than as dry compilers of public transactions. Yet it is a common piece of affectation, in those who pretend to be learned, to deride all modern abridgements of history, and to send the student at once to the fountain-head,-in which, if we may trust these counsellors, he will find a stream more full, as well as more pure, fresh from truth and nature, without any sophistication of philosophy. But, without the assistance of those who have brought together and arranged whatever is important in the records of antient times, we are bold to say, that little profit indeed could be reaped by their study, unless by those who should undergo the same labour with the same ability.

The greater part, by far, of those who wrote history before the 13th century, were not only ecclesiastics, but men separated from secular concerns. We have just noticed (and without exaggeration, though sarcastically) the effect which their condition had upon their tone of writing. During the midnight of Europe, scarce any layman possessed competent learning for the easiest li terary work; and no modern language was applied to any species of composition. A few songs and romances appear in the French and Provençal, in the 12th century; and, if Mr Southey is not deceived, the Spanish poem of the Cid, which he has lately published, is of the same age. In the 13th century, the twilight became brighter: a good deal of French prose of that time is extant; chiefly indeed laws and law-books, besides the history of Ville-Hardouin. Joinville, the companion of St Louis in his youth, from 1248 to 1254, finished, in his old age, these celebrated Memoirs. They are dedicated to Louis Hutin, eldest son of Philip le Bel; and, at the date of the dedication, the author must have been more than fourscore years old. Gibbon imagines him, indeed, to have been not less than ninety; but this is founded upon a miscalculation of his age. He could not have been born later than 1227, ince he was a knight in 1248; but there