TO THE MOST ILLUSTRIOUS LORD CHARLES, Cardinal and Prince of Lorraine, Primary Prelate of France.

Just as our soul, created for the perfect knowledge of this temple of Nature, finds its greatest rest and delight when it arrives at the primary causes and origins of things: so is it accustomed to be affected with the greatest pleasure when it has discovered, through tireless labors, some trace of those very principles, however slight. That this occurs is certain, because the principles of things themselves are supreme in their own kind, and in this respect are most similar to God, who nevertheless transcends all kinds of things. For this reason, they are so highly pleasing to a soul that has been divinely created and infused with the light of mind and spirit coming from without. For just as a likeness is accustomed to be delighted by its likeness, so the soul (for whose happiness all things subsist), like that cause which was first in the divine mind,