Elevation of the centering used in erecting the arches of the magazines at Purfleet, with estimates of the cost
Medium: Ink on paper
Plan of the gunpowder magazine at Purfleet in Essex. Five gunpowder magazines were erected in Purfleet in the 1760s, each measuring approximately 140ft by 20ft. Each building was divided into two rooms in which the gunpowder was stored. Approximately ten thousand barrels of gunpowder could be stored in each magazine and there were very strict rules for the construction of a magazine so that the danger of an accident was minimised. The doors were usually lined with material such as copper because copper is less likely to cause a spark which could cause the gunpowder to explode. The potential for an explosion meant that the magazines were built with very thick walls and were positioned in hollows in the ground so that any explosion would be forced upwards.