In the early 19th century, advances in optics and technology allowed for the development of more efficient lighthouse lenses. This report, written by Alan Stevenson, a leading expert on lighthouse design and construction, outlines the advantages and disadvantages of various types of lenses and recommends a course of action for the commissioners of northern lights. It is an essential resource for anyone interested in the history of lighthouse technology.

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.