Excerpt from The Year-Book of Facts in Science and Art: Exhibiting the Most Important Discoveries and Improvements of the Past Year in Mechanics and the Useful Arts; General Science; Electricity; Chemistry; Zoology and Botany; Geology and Mineralogy; Meteorology and Astronomy The iron dome at Vienna is, I believe, the largest vaulted roof in the world. I think it covers nine times the ground of the dome of St. Paul's, eight times the area of the dome of St. Peter's, and seven times the area of the dome of St. Sophia, at Constantinople. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.