make a brief extract from Hunt's "Merchants' Magazine" of 1854, as given in a foot-note in Maury's "Physical Geography of the Sea:"—
"Now, let us make a calculation of the annual saving to the commerce of the United 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 cts.; to California, also about 20 cts. The mean of this is a little over 19 cts. 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 (£468,750) 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
