In the Pacific, the steamer-route between San Francisco or Vancouver and China and Japan, instead of being as direct as a parallel of latitude, takes a southerly course when bound west, and a northerly course when bound east, the exact lines varying with the seasons as the prevailing winds and currents change. What these winds and currents are is explained in another chapter; but it is interesting to note that there is a difference of many miles in the ordinary westerly and easterly courses, the latter being much the shorter, although the vessels of the Canadian Pacific Line often sail so far north with the Japan warm current as to sight the Aleutian Islands. Sailing-vessels, moreover, curve so much farther south than steamers in going west from San Francisco, in order to take advantage of the equatorial current and the trade-winds, that the space is a thousand miles north and south between ships outward bound and those coming home. Between California and Honolulu a steamer takes a bee-line, but sailing-vessels find it best to make detours. In summer, when outward bound, this amounts to steering straight northward until under latitude forty degrees, before turning westward, making an angular course that looks very unnecessary to a landsman. [Illustration: A “WHALEBACK” FREIGHT STEAMER, ALSO ADAPTED TO PASSENGER SERVICE.] I have said that the finding of a sea-route to the East around the Cape of Good Hope was a great boon to western Europe, and advanced commerce. It remained so until within the last seventy-five years. Lately, the corsairs being out of the way, and safety guaranteed in Egypt, merchants and sailors both began to wish they had a shorter route between England and India. Then, with immense labor and sacrifice, the canal was cut across the Isthmus of Suez, and commerce returned to its ancient channel through the Red Sea, saving thousands of miles of weary distance. From the end of the Red Sea at Aden, the tracks of steamers both ways are straight courses to Bombay or Ceylon, and thence right up to Calcutta, across to Singapore, or down to Australia. Except East African coast lines, few steamers go around the Cape of Good Hope from England, excepting one line to South Australia, which steers straight eastward all the way from Cape Town to Adelaide, 6125 miles. But the Indian Ocean is so situated under the equator, is so filled with prevailing winds and currents and counter currents, that sailing-vessels must take very roundabout courses there, and can by no means steer the same track at all seasons of the year. These voyages from New York and London to the East are the longest regular sea-roads. A short table of distances between well-known ports along regular steamer-routes will be of interest; and by reversing them, or adding them together, the sailing distance between almost any two ports on the globe may be calculated.