When he wasn’t inventing logarithms, John Napier took a keen interest in military affairs. In 1596 he composed a list of war machines that “by the grace of God and worke of expert craftsmen” he hoped to produce “for defence of this Iland.” These included a piece of artillery that could “clear a field of four miles circumference of all living creatures exceeding a foot of height,” a chariot like “a moving mouth of mettle” that would “scatter destruction on all sides,” and “devises of sayling under water, with divers and other strategems for harming of the enemyes.”

No one knows whether Napier built his machines, but by World War I they were certainly realities — he had foreseen the machine gun, the tank, and the submarine.