_Fata vocant, conditque natantia lumina somnus._ --GEORGICS, iv, 496. Virgil is full of these picturesque expressions, with which he enriches the Latin language, and which are so difficult to be translated into our European jargons--the crooked and lame offspring of a well-formed and majestic sire, but which, however, have some merit of their own, and have done some tolerably good things in their way. There is an astonishing imagination, even in the science of mathematics. An inventor must begin with painting correctly in his mind the figure, the machine invented by him, and its properties or effects. We repeat there was far more imagination in the head of Archimedes than in that of Homer. As the imagination of a great mathematician must possess extreme precision, so must that of a great poet be exceedingly correct and chaste. He must never present images that are incompatible with each other, incoherent, highly exaggerated, or unsuitable to the nature of the subject. The great fault of some writers who have appeared since the age of Louis XIV. is attempting a constant display of imagination, and fatiguing the reader by the profuse abundance of far-fetched images and double rhymes, one-half of which may be pronounced absolutely useless. It is this which at length brought into neglect and obscurity a number of small poems, such as "Ver Vert," "The Chartreuse," and "The Shades," which at one period possessed considerable celebrity. Mere sounding superfluity soon finds oblivion. _Omne supervacuum pleno depectore manat._ --HORACE, _Art of Poetry_, 837. The active and the passive imagination have been distinguished in the "Encyclopædia." The active is that of which we have treated. It is the talent of forming new pictures out of all those contained in our memory. The passive is scarcely anything beyond memory itself, even in a brain under strong emotion. A man of an active and fervid imagination, a preacher of the League in France, or a Puritan in England, harangues the populace with a voice of thunder, with an eye of fire, and the gesture of a demoniac, and represents Jesus Christ as demanding justice of the Eternal Father for the new wounds he has received from the royalists, for the nails which have been driven for the second time through his feet and hands by these impious miscreants. Avenge, O God the Father, avenge the blood of God the Son; march under the banner of the Holy Spirit; it was formerly a dove, but is now an eagle bearing thunder! The passive imaginations, roused and stimulated by these images, by the voice, by the action of those sanguinary empirics, urge the maddened hearers to rush with fury from the chapel or meeting house, to kill their opponents and get themselves hanged.