The degree of exactness which Maury’s knowledge of the sea had reached is best illustrated by the incident of the _San Francisco_. This ship, bound from New York to San Francisco with a regiment of soldiers on board, was disabled in a hurricane on the day before Christmas, 1853 while crossing the Gulf Stream about 300 miles from Sandy Hook. Her position on the following day, and the next day after that, was reported by passing vessels which were, however, unable to render her assistance. Maury was then asked by the Secretary of the Navy to calculate her position for the assistance of the two relief ships which were to be dispatched in search of the unfortunate vessel. Although three other ships, the _Kilby_, the _Three Bells_, and the _Antarctic_, fell in with the wreck and rescued the remainder of her passengers, after 179 men had been washed overboard, yet it is an astonishing fact that Maury had so accurately guided the two searching revenue cutters that one of them went within sight of the spot where the drifting vessel had shortly before been found. There was still another important passage that Maury aided materially in shortening. This was the voyage from England to Australia and New Zealand. He opposed the British Admiralty route which passed near the Cape of Good Hope, and advised ships to sail 600 to 800 miles further westward and then to continue southward until they reached the prevailing strong westerly winds which drove the clippers onward at a tremendous rate. He advised them, when homeward bound, to continue in those “brave west winds” and return by way of Cape Horn. A voyage out to Australia and home again, accordingly, encircled the globe. Whereas by the old route it had taken about 120 days each way on the average, by Maury’s new route the passage for American sailings was decreased by one third and that for the British by about one fifth. This shortening of ships’ passages amounted to a vast saving to the commerce of the world. It was estimated that the annual saving to British commerce in the Indian Ocean alone, from Maury’s charts and sailing directions, amounted to $1,000,000 at least, and the amount saved to British commerce in all seas reached the stupendous sum of $10,000,000 annually. As to the United States, it has been conservatively estimated that the saving for the outward voyage alone from her Atlantic and California ports to those of South America, Australia, China, and the East Indies amounted to $2,250,000 per annum.