A regret has been often expressed, that Caesar, in his immortal Commentaries, should have confined himself to a narration of his own campaigns:  the astronomical commentaries of Laplace ascend to the origin of communities.  The labours undertaken in all ages for the purpose of extracting new truths from the heavens, are there justly, clearly, and profoundly analyzed; it is genius presiding as the impartial judge of genius.  Laplace has always remained at the height of his great mission; his work will be read with respect so long as the torch of science shall continue to throw any light.

The calculus of probabilities, when confined within just limits, ought to interest, in an equal degree, the mathematician, the experimentalist, and the statesman.  From the time when Pascal and Fermat established its first principles, it has rendered and continues daily to render services of the most eminent kind.  It is the calculus of probabilities, which, after having suggested the best arrangements of the tables of population and mortality, teaches us to deduce from those numbers, in general so erroneously interpreted, conclusions of a precise and useful character:  it is the calculus of probabilities which alone can regulate justly the premiums to be paid for assurances; the reserve funds for the disbursement of pensions, annuities, discounts, &c.:  it is under its influence that lotteries, and other shameful snares cunningly laid for avarice and ignorance, have definitively disappeared.  Laplace has treated these questions, and others of a much more complicated nature, with his accustomed superiority.  In short, the Theorie Analytique des Probabilites is worthy of the author of the Mecanique Celeste.

A philosopher, whose name is associated with immortal discoveries, said to his audience who had allowed themselves to be influenced by ancient and consecrated authorities, “Bear in mind, Gentlemen, that in questions of science the authority of a thousand is not worth the humble reasoning of a single individual.”  Two centuries have passed over these words of Galileo without depreciating their value, or obliterating their truthful character.  Thus, instead of displaying a long list of illustrious admirers of the three beautiful works of Laplace, we have preferred glancing briefly at some of the sublime truths which geometry has there deposited.  Let us not, however, apply this principle in its utmost rigour, and since chance has put into our hands some unpublished letters of one of those men of genius, whom nature has endowed with the rare faculty of seizing at a glance the salient points of an object, we may be permitted to extract from them two or three brief and characteristic appreciations of the Mecanique Celeste and the Traite des Probabilites.

On the 27th Vendemiaire in the year X., General Bonaparte, after having received a volume of the Mecanique Celeste, wrote to Laplace in the following terms:—­“The first six months which I shall have at my disposal will be employed in reading your beautiful work.”  It would appear that the words, the first six months, deprive the phrase of the character of a common-place expression of thanks, and convey a just appreciation of the importance and difficulty of the subject-matter.