This technical treatise offers a detailed examination of the theory and construction of helicoidal oblique arches. Culley provides a comprehensive analysis of the mathematical principles involved, and includes detailed drawings and diagrams throughout. A must-read for anyone interested in civil engineering or the history of architecture. 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.