One of his most important historical studies was A History of the Theories of Aether and Electricity, from the Age of Descartes to the Close of the Nineteenth Century (1910).
Isa ng kanyang mga pinaka-mahalagang kasaysayan ng pag-aaral ay isang Kasaysayan ng Theories ng Aether at Elektrisidad, mula sa Edad ng Descartes sa Isara ng ikalabinsiyam Century (1910).