In Asia they held Asia Minor and Syria, had sent expeditions into Arabia, and were acquainted with the more distant countries formerly invaded by Alexander, including Persia, Scythia, Bactria and India.
Actual or projected routes for telegraph cables across the deep sea have also been sounded with extreme accuracy in many cases; but beyond these lines of sounding the vast spaces of the ocean remain unplumbed save for the rare researches of scientific expeditions, such as those of the " Challenger," the " Valdivia," the " Albatross " and the " Scotia."
Before the Antarctic expeditions of 1903-1904 our knowledge of the form of the sea bottom south of 40° S.
Before the Roman legions were sent into a new region to extend the limits of the empire, it was usual to send out exploring expeditions to report as to the nature of the country.
Eight British government expeditions for observing total solar eclipses were conducted by him between 1870 and 1905.