OF THE FRANKLIN INSTITUTE OF THE State of Pennsylvania AND MECHANICS' REGISTER. DEVOTED TO MECHANICAL AND PHYSICAL SCIENCE, CIVIL ENGINEERING, THE ARTS AND MANUFACTURES, AND THE RECORDING OF AMERICAN AND OTHER PATENTED INVENTIONS. EDITED BY THOMAS P. JONES, M. D. MEMBER OF THE AMERICAN PHILOSOPHICAL SOCIETY, OF THE ACADEMY OF NAT- AND SCIENCES, MASSACHUSETTS, AND CORRESPONDING MEM- BER OF THE POLYTECHNIC SOCIETY OF PARIS. NEW SERIES. VOL. XXI. PHILADELPHIA: PUBLISHED BY THE FRANKLIN INSTITUTE, at their hall, & CO., NEW YORK; AND JOSEPH H. FRANCIS, BOSTON. JOURNAL OF THE FRANKLIN INSTITUTE OF THE State of Pennsylvania, AND MECHANICS' REGISTER. DEVOTED TO Mechanical and Physical Science, CIVIL ENGINEERING, THE ARTS AND MANUFACTURES, AND THE RECORDING OF AMERICAN AND OTHER PATENTED INVENTIONS. JANUARY, 1838. Practical and Theoretical Mechanics and Chemistry. On Hydraulic and Common Mortars. By General TREUSSART, Inspecteur du Genie. Translated from the French by J. G. Totten, Lt. Col. of Eng. and Brevet Col. United States Army. (CONTINUED FROM VOL. XX, P. 399.) ART. VII. Of Artificial Trass and Puzzalona. Mr. Baggé, a Swedish Engineer, was, I think, the first who attempted to make artificial puzzalona. This Engineer used, in his experiments, a species of black, and quite hard, schistus; he heated it highly several times; afterwards reduced it to powder, and having mixed it with lime, announced having obtained an excellent mortar, having all the properties of mortar made of puzzalona. I do not at all doubt the success of Mr. Baggé: but his experiments having been repeated elsewhere, a less satisfactory result was secured. This was owing to using schists of a different composition, and which, in lieu of being heated highly, like those of the Swedish Engineer, required to be heated moderately. Mr. Faujas de Saint-Fond made several researches in 1778 with the puzzalonas of Vivarais, which he found to be equal to the puzzalonas of Italy. He showed, also, that the trass of Andernach was a true puzzalona. In 1786 Mr. Chaptal repeated the experiments of Mr. Faujas de SaintVOL. XXI.-No. 1.—JANUARY 1838, 1 |