Antoine-Joseph Loriot's 1780 essay on a cement and artificial stone used by the Greeks and Romans is a landmark work in the history of construction materials. Loriot conducted extensive experiments with the material and developed techniques for its use in building construction. This English translation offers modern readers an opportunity to revisit Loriot's work and appreciate his contributions to the science of building materials. Architects, engineers, and historians of science will find this work indispensable. 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.