Microstructural and elemental study of a bullet from the Battle of Trinidad de Sarapiquí in 1856

Abstract

This study aims to generate a multidisciplinary understanding about the complexity of the historical battle in La Trinidad de Sarapiquí de La Campaña Nacional of 1856-1857, particularly in establishing a baseline diagnosis of the macrostructure, microstructure and elemental chemical analysis of a Minié bullet recovered from this historical event. We therefore carried out the first pilot study of a Minié ball recovered in 2016 in an excavation at the site of La Trinidad, in Sarapiquí, belonging to the Museo Histórico Cultural Juan Santamaría. In order to obtain information on both its internal and external structure, the techniques of optical microscopy, scanning electron microscopy and elemental analysis by energy dispersive X-rays were used to determine areas of interest in the bullet and also to specify the composition of the white patina which contains primarily three types of elements: Pb, C and O. Here, we identify the possible presence of cerussite crystals in the lead carbonate surface coating in a 165-year-old Minié bullet. It should be noted that knowing the rifle of origin and its bullet is evidence of great importance to contribute to the reconstruction of the historical context in which this event took place and will therefore allow us to establish which artifacts were being used at the time, both by national and Central American adversaries.