This classic work on optics was published in the late 17th century by David Gregory, a Scottish mathematician and astronomer, and his son James Gregory, who invented the reflecting telescope. The book includes contributions from Sir Isaac Newton and provides a comprehensive overview of the principles of catoptrics (the study of mirrors) and dioptrics (the study of lenses). This book is a must-read for anyone interested in the history of optics and the development of modern physics. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.