During his tenure as Chief Signal Officer of the Army, the following military telegraph lines were constructed, operated and maintained during the Spanish–American War: Puerto Rico, ; Cuba, ; the Philippines, . In connection with Alaska, then General Greely had constructed under very adverse conditions a telegraph system of nearly , consisting of submarine cables, land cables and wireless telegraphy, the latter covering a distance of , which at the time of installation was the longest commercial system regularly working in the world.