DEFILE, a military expression for a passage, to march through which troops are compelled to "defile," or narrow their front (from the Fr. defiler, to march in a line, or by "files") . The word is usually applied to a ravine or gorge in a range of hills, but a causeway over a river, a bridge and even a village may equally be called a defile. The term is also used to express, with out any special reference to military operations, a gorge among mountains. The verb "to defile" is used of troops marching on a narrow front, or narrowing their front, under all circumstances, and in this sense is the contrary of "deploy." "Defile," in the sense of "pollute," is another form of "defoul." DE FILIPPI, FILIPPO (1869-1938), Italian scientist and explorer, was born in Turin April 6, 1869. After graduating in medicine at the Turin University, he became assistant in the surgical clinic and lecturer in operative surgery in the Univer sity of Bologna. He published a number of important papers on physiological and biological chemistry. In 1897 he went with the Duke of the Abruzzi to Alaska as scientific observer and ascended Mount St. Elias. Although he did not accompany the Duke to the Ruwenzori in Central Africa in 1906, De Filippi wrote the report of the expedition. In 1909 De Filippi joined the Duke's expedition to the Western Himalaya and Karakoram Mts., where a point 24,600f t. high was reached on a ridge of the Bride Peak close to K2, which established a record of altitude unsurpassed until the exploits on Mount Everest (1922 and 1924). He later (1913-14) organized and led an important scientific expedition to the Karakoram range in Central Asia, under the auspices of the Indian and Italian Governments. He died Sept. 23, 1938.
He published The Ascent of Mount St. Elias, Alaska, by H.R.H. Prince Luigi Amedeo di Savoia, Duke of the Abruzzi (19oo), Ruwenzori (1909), Karakoram and Western Himalaya (1909) 2 vol. (1912) , and Storia della spedizione scientifica italiana nel Himalaia, Caracoritm e Turchestan Cinese, (1924)•