States effected by these charts and sailing directions.
According to Mr Maury, the average freight from the United States to
Rio Janeiro is 17.7 cents per ton per day; to Australia, 20 cents; to
California, also about 20 cents. The mean of this is a little over 19
cents per ton per day; but, to be within the mark, we will take it at
15, and include all the ports of South America, China, and the East
Indies.

"The sailing directions have shortened the passage to California 30
days; to Australia, 20; to Rio Janeiro, 10. The mean of this is 20; but
we will take it at 15, and also include the above-named ports of South
America, China, and the East Indies.

"We estimate the tonnage of the United States engaged in trade with
these places at 1,000,000 tons per annum.

"With these data, we see that there has been effected a saving for each
one of these tons, of 15 cents per day for a period of 15 days, which
will give an aggregate of 2,250,000 dollars (468,750 pounds) saved per
annum. This is on the outward voyage alone, and the tonnage trading
with all other parts of the world is also left out of the calculation.
Take these into consideration, and also the fact that there is a vast
amount of foreign tonnage trading between these places and the United
States, and it will be seen that the annual sum saved will swell to an
enormous amount."

Before the existence of the Gulf Stream was ascertained, vessels were
frequently drifted far out of their course in cloudy or foggy weather,
without the fact being known, until the clearing away of the mists
enabled the navigators to ascertain their position by solar observation.
Now, not only the existence, but the exact limits and action of this
stream are known and mapped; so that the current, which was formerly a
hindrance to navigation, is now made to be a help to it. The line of
demarcation between the warm waters of the Gulf Stream and the cold
waters of the sea is so sharp and distinct, that by the use of the
thermometer the precise minute of a ship's leaving or entering it can be
ascertained. And by the simple application of the thermometer to the
Gulf Stream the average passage from England to America has been reduced
from upwards of eight weeks to little more than four!

But this wonderful current is useful to navigators in more ways than
one. Its waters, being warm, carry a mild climate along with them
through the ocean even in the depth of winter, and thus afford a reg