Antonio de Gaver, a Spanish military engineer, oversaw the construction of castles, forts, and other military installations in Spain and on the Spanish-Portuguese border beginning as early as 1719, and he was a prolific cartographer and surveyor. Gaver is also recorded as director of the Academy of Mathematics of Oran in 1739, one of the Barbary ports in North Africa that had been the target of repeated Spanish incursions for over two centuries. Although the APS has had Gaver's manuscript treatise on the fortifications at Oran y Mazalquivir since Joel Poinsett donated in 1820, it wasn't until almost 185 years later that we acquired the accompanying map.

Louis Hasbrouck was a senior at Princeton in 1796-1797 when he attended the chemistry lectures given by John Maclean. In only his second year at Princeton, Maclean was rapidly becoming known for introducing the latest currents in chemical theory to the United States, including the system of Antoine Laurent Lavoisier, and he was one of the first Americans to insist that students take part in active experimentation. Hasbrouck's notes thus offer insight into a critical period in the history of American chemistry.