Donald H. Keith

Less is More: Measure of Chloride Removal Rate from Wrought Iron Artifacts During Electrolysis

Abstract Electrolysis performs three useful functions for the conservator: it mechanically cleans artifact surfaces, removes salt, and (theoretically) reduces corrosion products. Because each of these functions is fundamentally different, they must be separated for study. Mechanical cleaning and the reduction of corrosion products during electrolysis are recognized as relatively minor effects; therefore, from the perspective of the archaeological conservator, the most important function is chloride removal. The authors implemented a study to discover what current density most efficiently promotes this function with respect to wrought-iron artifacts recovered from marine environments. Complete data are presented for three experiments performed on archaeological specimens in which current was controlled and the quantity of chloride removed was measured. Over the course of four experiments, the lower current density of 50μ.A. cm-2 removed an average of 4·9 times more chloride (expressed in mg.A-1hr-1) than a higher current density of 200A. cm-2.

The Search for Columbus' Caravel Gal1ega and the Site of Santa María de Belén

AbstractHistorical research, geomorphological reconstruction, test excavation, and remote sensing are being applied to the search for the caravel Gallega and the outpost Santa Maria de Belen abandoned by Christopher Columbus in 1503. Comparison of modern geographical features with descriptions contained in historical documents identified Rio Belen, Panama, as the most promising locality to search. In spite of unexpected difficulties presented by the physical environment, remote sensing surveys and test excavations revealed anomalies and historical artifacts that may be associated with the target sites.

The Tide of History

Two stories are told simultaneously: one that may have been, and one that yet might be. The story of the voyage that might have been is based on archaeological evidence provided by the earliest shipwreck discovered in the New World. These two stories are set in different eras to demonstrate certain constants in the human drive to explore the unknown, in the methods used, and in the consequences encountered.

Vanguard of Empire: Ships of Exploration in the Age of Columbus

Roger Smith has assembled from fragmentary evidence a portrait of the small vessels invented and refined in the shipyards of Spain and Portugal half a millennium ago. The work focuses on the advances in maritime technology that made the European conquest of the New World possible. In addition to covering these developments, Smith shows readers how ships were built, outfitted and manned, illustrating what life at sea was like in the late fifteenth and early sixteenth centuries. In focusing on the advances in maritime technology that made European expansion possible, Vanguard of Empire sheds light in 1992 on a neglected aspect of the European conquest of the New World.