The first chemical writer that excites our notice is Becher. This man collected all the facts which were noticed before him, and pointed out many important objects to which the researches of chemists ought to be directed. The publication of his Physica Subterranea, in 1669, forms a very important æra in the history of chemistry. At that period chemistry escaped for ever from the trammels of alchymy, and became the rudiments of the science which we find at present. Becher distinguished himself so highly by his chemical knowledge as to cause the names of all former theorists to be forgotten, after having laid the foundation of the famous system of phlogiston. He died in the year 1682.

Soon after his death arose one of his pupils, whose name was Stahl. He simplified and improved the doctrine of his master so much that he made it entirely his own; and accordingly it has been known ever since by the name of the Stahlean Theory. (See Appendix No. 1) He was the first who had a clear notion of chemical union, and gives many instances of double elective attractions. His writings have done him immortal honour, and ranked him amongst the first characters of the age in which he lived. He died in the year 1704.

Ever since the death of these chemists chemistry has been cultivated with success. Men of eminence have appeared every where; discoveries have been multiplied which led to numerous important facts. The names of Margraaf, Scheele, Bergman, Baume, Rouelle, &c. will remain distinguished in the annals of chemical science.

The spirit of chemical inquiry which these philosophers had infused summoned on a sudden into action the faculties of the most learned men of Europe. Several of the invisible agents which form so important a part in the economy of nature, were discovered. Dr. Priestley discovered, in 1777, various aerial fluids, formerly totally unknown to chemists; Dr. Black traced the laws of latent heat, and discovered the carbonic acid. The science of electricity was as it were created, the thunder was taken from the clouds, and the properties of the atmosphere were examined with accuracy.

All these new discoveries embarrassed the votaries of the doctrine of Stahl; and the conclusions to which they led were of such a nature as to puzzle and to contradict

many of the laws of the science. It was requisite to take but one step further that the doctrine of phlogiston might be exploded for ever. This was left to Lavoisier.

Lavoisier, endowed by nature with the most happy genius for science, and favoured by his own princely fortune and the liberal bounty of the French government, instituted a series of ingenious and accurate experiments, the result of which proved to demonstration that the theory of phlogiston was founded in error. His experiments were repeated, under every diversity of circumstances, by all the philosophers of Europe: his reasonings and inferences were vigorously attacked by the defenders of the phlogistic theory; a kind of chemical war was thus kindled in the republic of letters, which was carried on with great animosity; and posterity will see with regret men of undoubted genius at times divesting themselves of the armour of truth and candour, and endeavouring to serve their party and stab their adverse fellow-labourers with darts steeped in the poison of calumny and falsehood. These things have passed away: the contest has been productive of good effects, which infinitely surpass the bad ones: it has occasioned an accumulation of facts, produced a rigid examination of theories and opinions, introduced accuracy in chemical experiments, and given that tone and vigour to the cultivators of chemistry which have brought to light the most sublime and unlooked for truths.

The principles of Lavoisier have triumphed, and are now taught in all the schools of Europe: his opponents have become his disciples; and thus he has erected the luminous and beautiful theory of chemistry which all the chemists of Europe have now adopted. What a pity that the sanguinary tyranny of Robespierre should not even have spared this man! who perished on the 7th of May, 1794, under the axe of the guillotine.

Thus chemistry is become an entirely new science. It is no longer confined to the laboratory of the arts: it has extended its flight to the sublimest heights of philosophy, and pursues paths formerly regarded as impenetrable mysteries. Placed for ever in the elevated rank it now holds, rich with all its new conquests, it is become the science most adapted to the sublime speculations of philosophy, the most useful in advancing all the operations of

the arts, and the most rational for scientific amusement. Exact in its process, sure in its results, varied in its operations, without limits in its applications and its views, severe and geometrical in its reasoning, there is scarcely any human occupation which it does not enlighten, and upon the perfection of which it may not have great influence. It bestows enjoyment to every class of individuals and who would not be ambitious of becoming acquainted with a science which enlightens almost every species of human knowledge?

Amongst the number of philosophers who have since that time cultivated and enriched the new theory of chemistry with discoveries which will for ever give immortality to their names, we have to notice Aikin, Allen, Babington, Bancroft, Beddoes, Blagden, Cavendish, Chenevix, Chrichton, Cruikshank, Dalton, Davy, lord Dundonald, lord Dundas, Fordyce, Garnett, Hatchett, Henry, Higgins, Hope, Howard, Kirwan, bishop of Llandaff, Murray, Nicholson, Pearson, Pepys, Tenant, Tilloch, Thomson, Wedgwood, and Wollaston; Achard, Arago, Biot, Crell, Gilbert, Gren, Goetling, Humbold, Hermbstaedt, Klaproth, Lowitz, Richter, Scherer, Tromsdorf, Westrumb, Wiegleb; Berthollet, Chaptal, Fourcroy, Lagrange, Guiton, Van Mons, Proust, Sequin, Vauquelin, Gay Lusac, Thenard, &c. &c.

THE material universe presents itself to an enlarged human observation as an immense assemblage of systems within systems, each complete in itself, yet connected, by numberless relations, with all around it; a larger still including a less, till all nature is, in this last grand result, comprehended in-ONE WHOLE.

The laws of this vast universe can be studied by us only in its inferior subdivisions. We conceive of it as subdivided into planetary systems. Comets are the only agents of combination among these systems with which we have any tolerable acquaintance. It is from the consideration of the appearances of that particular system to which our earth belongs that all our science concerning the laws of material nature is derived. When we confine our views to the globe we inhabit, we discover a vast variety of substances which may well excite our curiosity and arrest our attention. We perceive our earth to be a solid globe, composed of an assemblage of substances considerably fixed, and not to be destroyed without a considerable force of impulse. We observe a large part of it covered with an ocean, and numberless streams of cold liquid matter tending with great activity to incessant motion.

Around this earth and water, to a great but unknown height, is circumfused an atmosphere of an impalpable gazeous fluid, intermingled with portions of every solid

or aqueous matter that by an extreme comminution is capable of suspension in this aerial fluid.

Different opinions have been formed concerning the question, in what manner our earth was brought into the present distribution of its parts.

An origination of this globe out of a chaos was the general belief of the ancients. Moses, in the beginning of the pentateuch, gives an account of a series of successive changes, which he represents as the first which took place, from the moment at which matter was made subject to the laws it now obeys to that æra at which it was finally fit for the residence and support of animals, and had living inhabitants, brute and human, placed upon it. In modern times, different classes of speculatists have attemped to investigate the circumstances which must have attended the origin of it.

DIVINES have endeavoured to justify the account of Moses, by an appeal to the present laws of nature : but Burnet and others have been easily convicted of supposing primæval states of things utterly incompatible with these

laws.

CHEMISTS have conceived that the origin of the earth, in its present form, is from a general liquidity of its whole matter: others again have attributed it to the action of fire.

ASTRONOMERS have been persuaded that it was owing to the action of some comet, or to an altered arrangement of the planets.

OTHERS have conceived the idea of a world perhaps without beginning, but by the action of internal fires, with volcanic orifices, continually lacerated, undermined, and subverted, with the constant rise of a new earth, the residue and product from those fires, by which the former was demolished.

OTHERS, again have fancied a continual flitting of the ocean around the globe; by which that which was lately land becomes now the bottom of the sea, and that which is now covered by the sea is again to become land.

These fanciful opinions, to say nothing of the impious nature of some of them, have generally rather resembled philosophical dreams than the conceptions of waking and sober reason. Their authors, in forming them, have been too often guided by imagination more than judgment; and