beginning of the last century, I have only noticed such authors as conduced by the weight or novelty of their writings, the importance of their discoveries, or the example of their zeal, to the more immediate progress and elucidation of this department of philosophy. The annals of a period so extensive must necessarily record a host of experimentalists, to whose researches it would upon the one hand be impossible to do justice; and whose names, on the other, it would be useless to repeat. It may however be remarked, that alembics, and other complex distillatory apparatus, were employed by the alchemical physicians who flourished between the ninth and thirteenth centuries. Mesue mentions the distillation of rose-water, and the production of spirit of wine is noticed by Raymond Lully. At this time, too, furnaces of peculiar construction, and a variety of complex apparatus and accoutrements, were introduced into the laboratory.

During the fifteenth and sixteenth centuries, Alchemy was at its acmé, and many were the unwary and avaricious who were entrapped by the golden prospects and plausible mysticism of the art. Among them was that admirable artist Mazzuoli of Parma, better known under the name of Parmagiano.

Curious discoveries and useful inventions multiplied rapidly during the seventeenth century. Kunckel, in Saxony, successfully promoted the Chemistry of the Arts. In 1669, Brandt of Berlin discovered Phosphorus, and about the same time Homberg accidentally produced a spontaneously inflammable compound, which he called Pyrophorus. In 1674 the elder Lemery acquired great and deserved fame at Paris as a chemical lecturer. He was the first who threw aside the affected and pompous diction habitually indulged in by his predecessors and contemporaries, and adopted a simple and perspicuous style, which at once tended to the ready diffusion of his subject, and to its permanent popularity. When he published his course, " it sold" says Fontenelle "like a novel or a satire."

The establishment of literary and scientific societies during this age was another grand step towards the promotion of knowledge, and the period was particularly propitious to their progress. Bacon, Galileo, and Kepler, had opened that road to truth which was so eagerly and successfully pursued by Boyle, Hooke, and Mayow, in this country, and in which the miraculous mind of Newton displayed its brilliant powers. In Germany, Beccher and Stahl are entitled to particular mention. The suggestions of the former, who was a man of an acute and inquisitive turn of mind, led the latter into that train of speculation which terminated in producing the Phlogistic Theory, and which will presently be more particularly considered. Homberg, Geoffroy, and

the two Lemerys, were zealous followers of experimental chemistry in France, at the establishment of the Royal Academy of Sciences. In short, the independent zeal and healthy activity in scientific pursuit, which has since marked its progress in Europe, became manifest early in the seventeenth century; and the causes I have attempted to unfold contributed to the splendour which it began to acquire about the end of that important era in the general history of the world. The clouds of ignorance and error quickly dispersed before this happy dawn of true knowledge; and science, no longer enveloped in scholastic mystery and absurd speculation, began to display those inherent charms, which gained her the courtship and admiration of every liberal and cultivated mind, and which laid the foundation of that extended dominion which she acquired in the succeeding age.

SECTION II.

STATE OF CHEMISTRY AT THE OPENING OF THE EIGHTEENTH CENTURY.-OPINIONS OF BECCHER AND STAHL RESPECTING THE PHENOMENA OF COMBUSTION, COMPARED WITH THE VIEWS OF REY AND MAYOW.-PNEUMATIC CHEMISTRY OF HAILES AND BOERHAAVE. INVENTION OF THE THERMOMETER.

THE history of the progress of Chemistry during the seventeenth century presents many active and able inquirers, whose researches tended to develope new properties and combinations of bodies; but their attempts at theory and generalization were, with few exceptions, absurd and abortive. They consisted in wild hypothesis and vague speculation, and were founded, not upon the sober and steady basis of truth, but upon the unreal and tottering visions of the imagination. The spirit of Lord Bacon was slow in animating experimental philosophy, until Newton rose to surprise and illu'mine the world. It then assumed a new and cheerful aspect, and quick was its growth, and illustrious its progress, under the invigorating influence of that sun of science. : Although Chemistry does not lie under the same weighty obligations to Newton as

1 Those who are desirous of consulting the alchemical authors, and of becoming particularly acquainted with the titles of their voluminous productions, will find a curious body of information on these subjects in the Histoire de la Philosophie Hermetique, Paris, 1742.-Gobet's Anciens Mineralogistes, published at Paris in 1779, gives some details of the early progress of Mineralogical Chemistry in France.

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'mechanical philosophy, he conferred upon it a great and lasting benefit, by the disclosure of those clear and simple views which have already been alluded to. The important deductions, too, which flow in easy perspicuity from his experimental researches, soon became general models of imitation; and the new style which we discern in the philosophical authors of the early part of the eighteenth century throughout Europe, may, in a great measure, be referred to the lofty example before us.

No sooner was the spell of Alchemy broken, than the phenomena of combustion began to attract the notice of the early chemical theorists. The influence of the air upon this process had been long observed, and many of the changes suffered by the com

The following passages, in addition to the previous observations in the text, will be sufficient in illustra tion of Newton's views of Elective Attractions.

"Have not the small particles of bodies certain powers, virtues, or forces, by which they act at a distance, not only upon the rays of light, for reflecting, refracting, and inflecting them, but also upon one another, for producing a great part of the phenomena of nature? for, it is well known, that bodies act one upon another by the attractions of gravity, magnetism, and electricity; and these instances show the tenor and course of nature, and make it not improbable that there may be more attractive powers than these. For nature is very consonant and conformable to herself. How these attractions may be performed I do not here consider; what I call attraction may be performed by impulse, or by some other means unknown to me. I use that word here to signify only, in general, any force by which bodies tend towards one another, whatsoever be the cause. For we must learn from the phenomena of nature what bodies attract one another, and what are the laws and properties of the attraction, before we inquire the cause by which the attraction is performed. The attraction of gravity, magnetism, and electricity, reach to very sensible distances, and so have been observed by vulgar eyes, and there may be others which reach to so small distances as hitherto escape observation, and perhaps electrical attraction may reach to such small distances even without being excited by friction. For, when salt of tartar runs per deliquium, is not this done by an attraction between the particles of the salt of tartar and the particles of the water which float in the air in the form of vapours? And why does not common salt, or saltpetre, or vitriol, run per deliquium, but for want of such an attraction? Or why does not salt of tartar draw more water out of the air than in a certain proportion to its quantity, but for want of an attractive force after it is satiated with water? And whence is it but from this attractive power that water, which alone distils with a gentle and lukewarm heat, will not distil from salt of tartar, without a great heat? And is it not from the like attractive power, between the particles of oil of vitriol and the particles of water, that oil of vitriol draws to it a good quantity of water out of the air; and, after it is satiated, draws no more, and in distillation lets go the water very difficultly? And when the water and oil of vitriol, poured successively into the same vessel, grow very hot in the mixing, does not this argue a great motion in the parts of the liquors? And does not this motion argue that the parts of the two liquors, in mixing, coalesce with violence, and, by consequence, rush towards one another with an accelerated motion? And when aqua-fortis, or spirit of vitriol, poured upon filings of iron, dişsolves the filings with a great heat and ebullition, is not this heat and ebullition effected by a violent motion of the parts?" &c. "When spirit of vitriol, poured upon common salt or saltpetre, makes an ebullition with the salt, and unites with it, and, in distillation, the spirit of the common salt or saltpetre comes over much easier than it would do before, and the acid part of the spirit of vitriol stays behind ;-does not this argue that the fixed alcaly of the salt attracts the acid spirit of the vitriol, more strongly than its own spirit; and, not being able to hold them both, lets go its own?"-Newton's Optics, Opera omnia, 4to, Lond. 1782..

bustible had been examined with a surprising degree of acuteness and precision; for fire was almost the only agent employed at that period to effect combination and decomposition. These inquiries constitute a prominent feature in the history of Chemistry. It may therefore be requisite to pursue them with a minute attention, which may at first appear tedious, but which will gain in importance and interest as they proceed.

The first speculations in theoretical Chemistry deserving attention, are those of John Joachim Beccher of Spires, who died in England in 1685. He gained considerable celebrity at Vienna and Haerlem, for improvements in arts and manufactures, but was induced to retire to this country, in consequence of the jealousy of rivals, and the neglect of those upon whom he had conferred benefits. His works abound in shrewd and witty remarks, and in deep and curious reasoning,-in frivolous subtilty, and in weighty and sensible observations. His hypothesis respecting the origin of the varieties of matter, from the mutual agencies and combinations of a few elementary principles, though unnecessarily blended with scriptural history, are characterized by considerable brilliancy of thought and originality of invention. They are detailed at great length in his Physica Subterranea, which treats on the original creation of matter, and the transition and interchange of elements. The Institutiones Chemica, or Edipus Chemicus, of this author, is another curious production, containing the history of the chemical elements, and describing the leading operations of the laboratory. Earth was the favourite element of this philosopher, of which he supposed three varieties to exist, namely, a vitrifiable, a metallic, and an inflammable earth. Of these the various productions of nature were formed. '

1 Beccher wrote voluminously upon a great variety of subjects. His principal chemical works are as follows.

1. Oedipus Chemicus. 2. Metallurgia, de generatione, refinatione, et perfectione Metallorum. 3. Physica Subterranea, and its various appendices. 4. Parnassus Medicinalis Illustratus. 5. Laboratorium Portatile. 6. Chymischer Rosen-garten.

Beccher's Oedipus is dedicated to Francis Sylvius Deleböe, who, in 1658, was elected the first Professor of Medicine in the University of Leyden. He was a man of an acute mind, as appears from his various essays and tracts, more especially from his Praxeos Med. Idea Nova. He died at Leyden in 1672. "Utilissimum profecto munus subiisti, quo tui auditores non verba sed corpora, non chymerasticos terminos, verum ipsas reales enchyrises, non inanes denique et immateriales facultates, sed a te demonstrati, effectus causas practicas audiunt, vident, tangunt." Beccher everywhere compliments him as a man not of words, but of deeds; as a philosopher, who eminently sought to render science popular and intelligible to all capacities.

The language of Beccher's Physica Subterranea is sufficiently inelegant and incorrect. "Excuso Latini

But the most celebrated chemical theorist of the latter part of the seventeenth century is Ernest Stahl, born at Anspach in Franconia, in 1660. He adopted many of the opinions of Beccher respecting the cause of inflammability, and upon these foundations reared the celebrated System of Phlogiston, according to which, inflammability is supposed to depend upon the presence of a highly subtile and elastic matter, which, at certain temperatures, is thrown into violent motion, and appears under the form of flame or fire. Combustion is the separation of this principle, and bodies contain it in various proportions. Charcoal, for instance, when burned, leaves scarcely any residuum, and is, therefore, nearly pure phlogiston. Antimony, when burned, affords a large proportion of earthy matter. If this earth be heated with charcoal, or other matter abounding in phlogiston, antimony is regenerated; this metal, therefore, is a compound of earth and phlogiston.

If sulphuric acid, which is not inflammable, be distilled with oil of turpentine, which is extremely so; or, in other words, if phlogiston be added to sulphuric acid, sulphur is obtained. Sulphur, therefore, is a compound body, consisting of sulphuric acid and phlogiston. If sulphur and common potash be fused together, a brown compound is obtained, formerly called liver of sulphur, and the same product results when charcoal is heated with Glauber's salt, which consists of soda combined with sulphuric acid. Such was Stahl's explanation of the phenomena of combustion, and such the apparently plausible experimental proofs upon which it was founded.

In Germany and in France, the phlogistic doctrine was received with that thoughtless and eager enthusiasm which suffers the blaze of novelty to eclipse the steady light of truth, and which is rather captivated by plausible exterior than by internal excellence. Even in this country the experiments of Boyle and of Hooke, if not forgotten, were over

tatem in hoc opere," says he, "quam barbaram esse fateor, ob materiem et ob scriptionem, in specie scriptionis modum: ex ore enim dictantis totum opus conceptum est. Sic rebus attentus, verba neglexi." This is at once an example and apology.

1 Stahl's doctrines are very ably set forth in his Three Hundred Experiments, published at Berlin in 1731; and in his Fundamenta Chemiæ, Nuremberg, 1723 and 1732. He observed the necessity of air to combustion, and considered flame or fire as resulting from its violent etherial agitations. Stahl is continually urging circumspection in hypotheses, yet preconceived opinions are always leading him to erroneous conclusions, as the following passages amply prove. "Aer ignis est anima, hinc, sine aere nihil potest accendi vel inflammari."—" Aer in motum excitatus, seu ventus artificialis, vel etiam naturalis, mirum excitat motum ætheris, seu flammam; hinc ad ignem fusorium, et vitrificatorium, promovendum, follibus opus est; imo gradus et vehementia ignis dependet multum ex aeris admissione." Fund. Chem. dogmat. et ration. p. 22.