Dioptrics

...I saw that Your Highness was wonderfully delighted, they provoked me to an emulation of the same duty. Even if these singular causes did not impel me to dedicate this Dioptrics original: "Dioptricen"; the study of the refraction of light, particularly through lenses. of mine to Your Most Reverend and Serene Highness: then this one reason alone would suffice in general—that mathematical treatises, being remote from the common grasp and therefore held in contempt, are offered to no one more rightly than to those who are able to judge them; those whom Nature has equipped with a sharp intellect, and whom a love of philosophy original: "philosophiæ"; in this era, this referred to "natural philosophy," what we now call science. and meditation have led to a perfect knowledge of these matters. In which knowledge, whether you have any equal among the leading men of this time is unknown to me; certainly, among the professors of the Universities, those who are equal to this judgment are found to be fewer than is common.

Indeed, if in the very frequent dedications of books, no praises of Patrons were more artificial than these, I believe the trust that dedications have almost exhausted regarding the virtues of Patrons would soon be restored. And for this very purpose, I refrain from recounting the rest of Your Most Reverend and Serene Highness’s virtues (as is usually done in dedications); lest the cobbler seem to wish to be wise beyond his bench original: "ne sutor ultra crepidam"; a classical proverb suggesting one should stay within their own area of expertise. Kepler, as a mathematician, modestly limits his praise to the Prince's mathematical talents..

For the rest, I hang no other ivy original: "hederam"; a reference to the proverb "good wine needs no ivy bush," meaning a good product needs no advertisement. Kepler suggests the Prince's approval is the only "sign" or advertisement the book needs. for the reader than to indicate to him that this little book has been approved by such a prince and ordered to be published. And now I most submissively commend myself to Your Most Reverend and Serene Highness. Farewell: The Kalends of January original: "Cal. Ianuarijs"; January 1st, 1611..