Scientific American Supplement, No. 643, April 28, 1888

The first portrait offers a vivid glimpse of the German Crown Prince William, heir to the Hohenzollern throne in the late 19th century. Raised in a household where military tradition was paramount, he is shown as a diligent officer deeply involved with his regiment of red hussars and even dressing his young son in a guard uniform. The narrative also touches on his frail health, hinting that his impending succession may be uncertain, while emphasizing his close ties to the era’s leading statesmen.

The second profile turns to General François Perrier, a French engineer whose career bridged military service and groundbreaking scientific work. Born to a Protestant family in the Cévennes, he rose through the ranks of the army while pioneering large‑scale geodetic surveys across France, Corsica, Algeria and even the United States during the 1882 Venus transit. His leadership of the army’s geographical service and his role in international boundary conferences illustrate how meticulous fieldwork and precise instrumentation reshaped the understanding of the Earth’s shape in his time.