dred and seventy-six years before Christ, and each Olympiad includes four years.

The Roman era was the building of their city, the Eternal City,' as they loved to call it.

6

The Mohammedans* date from the Hegira, or flight of Mohammed from Mecca, his birthplace, to Medina, A. D. 622; and they have this advantage, that they began almost immediately to use it.

The era, used all over the Christian world, is the birth of Christ. This was adopted, as a date, about A. D. 360.

Julius Scaligert formed an era, which he called the Julian period, being a cycle of seven thousand nine hundred and eighty years, produced by multiplying several cycles into one another, so as to carry us back to a period seven hundred and sixty-four years before the creation of the world. This era, standing out of all history, like the

* Followers of Mohammed, a celebrated impostor, who was born at Mecca, in Arabia, A. D. 569, and died at Medina, in the same country, A. D. 632. He was the founder of a system of religious belief, which is still adhered to by the Turks. This system he began to promulgate, A. D. 609, and continued to preach it till A. D. 622, when, owing to a conspiracy formed against his life, he fled from Mecca to Medina, where he was well received. It is from this flight, (for this is the meaning of the word Hegira,) that the Mohammedans commence their reckoning. - J. W. I.

+ The Julian period was not formed by Julius Scaliger, but by his son, Joseph Justus Scaliger, who was born A. D. 1540. It is so called, because it contains a certain number of Julian years, or years arranged according to a mode of reckoning introduced by Julius Cæsar, emperor of Rome. - J. W. I.

fulcrum which Archimedes* wished for, and independent of variation or possibility of mistake, was a very grand idea; and, in measuring everything by itself, measured it by the eternal truth of the laws of the heavenly bodies. But it is not greatly employed, the common era serving all ordinary purposes.

You will, perhaps, ask, if we have no eras, what have we to reckon by? We have generations and successions of kings. Sir Isaac Newton, who joined wonderful sagacity to profound learning and astronomical skill, made very great reforms in the ancient chronology. He pointed out the difference between generations and successions of kings. A generation is not the life of man; it is the time that elapses before a man sees his successor; and this, reckoning to the birth of the eldest son, is estimated at about thirty years. The succession of kings would seem, at first sight, to be the same, and so it had been reckoned: but Newton corrected it, on the principle, that kings are often cut off, prematurely, in turbulent times, or are succeeded, either by their brothers, or by their uncles, or others, older than themselves. The lines of kings of France, Eng

* Archimedes was the most celebrated among ancient geometricians, and was born about two hundred and eighty-seven years before the birth of our Saviour. He is said to have been the inventor of many mechanical powers, such as the compound pulley, the endless screw, and others; and is reported to have said, he would move the earth, if he had a point, or fulcrum, without it, on which to stand, and place his lever.-J. W. I.

land, and other countries, within the range of exact chronology, confirmed this principle. He therefore rectified all the ancient chronology, according to it; and, with the assistance of astronomical observations, he found reason to allow, as the average length of a reign, about eighteen or twenty years.

But after all, great part of the chronology of Ancient History is founded upon conjecture, and clouded with uncertainty.

Although I recommend to you a constant attention to chronology, I do not think it desirable to load your memory with a great number of specific dates, both because it would be too great a burden on the retentive powers, and because it is, after all, not the best way of attaining clear ideas, on the subjects of History. In order to do this, it is necessary to have in your mind, the relative situation of other countries, at the time of any event recorded in one of them. For instance, if you have by heart the dates of the accession of the kings of Europe, and want to know, whether John lived at the time of the Crusades, and in what state the Greek empire was, you cannot tell without an arithmetical process, which, perhaps, you may not be quick enough to make. Nay, you may read separate histories, and yet not bring them together, if the countries be remote. Each exists in your mind, separately, and you have, at no time, the state of the world. But you ought

to have an idea, at once, of the whole world, as far as History will give it. You do not see, truly,

what the Greeks were, except you know that the British Isles were then barbarous.

A few dates, therefore, perfectly learned, may suffice, and will serve as landmarks, to prevent your going far astray in the rest: but it will be highly useful to connect the histories you read, in such a manner, in your own mind, that you may be able to refer from one to the other, and form them all into a whole. For this purpose, it is very desirable to observe, and retain in your memory, certain coincidences, which may link, as it were, two nations together. Thus you may remember, that Haroun al Raschid* sent to Charlemagnet the first clock that was seen in Europe.

It may be desirable to keep one kingdom as a measure for the rest. Take, for this purpose, first, the Jews, then, the Greeks, the Romans, and, because it is so, your own country then harmonize and connect all the other dates with these.

That the literary history of a nation may be connected with the political, study also biography, and endeavor to link men of science and literature, and artists, with political characters.

These are some of the kind of dates, which make every thing lie in the mind, in its proper order;

* A celebrated caliph (or ruler) of the Saracens, a people of Asia, who flourished about the year 786. —J. W. I.

+ Charlemagne, (or Charles the Great,) emperor of the West, ruled over an immense empire, which included France, a great part of Germany, Italy, Caledonia, Navarre, Arragon, the Netherlands, and many other countries. He died in the year 814. J. W. I.

they also take fast hold of it. If you forget the exact date, by years, you have nothing left; but, of circumstances, you never lose all idea. As we come nearer to our own times, dates must be more exact. A few years, more or less, signify little in the destruction of Troy, if we knew it exactly; but the conclusion of the American war should be accurately known, or it will throw other events near it into confusion.

Painting is a good auxiliary; and though, in this country, History is generally read before we see pictures, they mutually illustrate one another. Painting also shows the costume. In France, where pictures are more accessible, there is more knowledge generally diffused of common History. Many have learned Scripture History, from the rude figures on Dutch tiles. Farewell; and believe me, yours affectionately.

HYMN.

COME, let us walk abroad; let us talk of the works of God.

Take up a handful of sand; number the grains of it; tell them, one by one, into your lap. Try, if you can count the blades of

field, or the leaves on the trees.

grass in the

We cannot count them, they are innumerable; much more, the things which God has made.