The distinction between history and biography lies so much on the surface that a confusion between them is barely justifiable. History may be compared to mechanics, the science which determines the power of bodies in the mass. Biography may be compared to chemistry, the science which analyses substances and resolves them into their constituent elements. The historian has to describe the aggregate movement of men and the manner in which that aggregate movement fashions political or social events and institutions. The historian has only to take into account those aspects of men's lives which affect the movements of the crowd that co-operates with them. The biographer’s concern with the crowd is quite subsidiary and secondary. From the mass of mankind he draws apart those units who are in a decisive degree distinguishable from their neighbours. He submits them to minute examination, and his record of observation becomes a mirror of their exploits and character from the cradle to the grave. The historian looks at mankind
