He analyzed sunspot records (and approximated records), comparing them to riots, revolutions, battles and war in Russia and seventy-one other countries for the period 500 BCE to 1922 CE. (A process known as historiometry.) He found that a significant percent of what he classified as the most important historical events involving large numbers of people occurred around sunspot maximum.
He examined sunspot data (and estimated records), correlating them to riots, revolutions, battles, and wars in Russia and seventy-one other nations from 500 BCE to 1922 CE. (A method known as historiometry.) He discovered that a substantial portion of the significant historical occurrences involving large groups happened near sunspot peaks.