In 1843 he wrote a notable treatise, entitled “The Gulf Stream and its Causes.” These and other contributions to science were written under the pen name of “Harry Bluff.” They attracted so much attention and were so generally approved by the navy that the officers had great numbers of the papers printed and circulated. When it became known that the young Lieutenant Maury was the author of these papers, his ability and grasp of mind were universally recognized, and his position as authority on naval questions was established. Soon after he was placed in charge of the Depot of Charts and Instruments, which office he developed into “The National Observatory and Hydrographical Department of the United States.” In a speech before the Senate John Bell said: “No man could have been found in the country better fitted than Maury for this difficult duty, and he worked with the zeal and energy expected of him.” At this time he gave to the world the famous “Winds and Currents Charts and Sailing Directions.” Seamen were at first distrustful of the new charts, fearing that a route which could save from ten to twenty days on an outward voyage, was fraught with danger. At last a Baltimore vessel determined to follow the new chart. The voyage was a complete success, for he made both trips in the time consumed under the old system in the outward passage alone. There was now no hesitation about the use of the charts. Active interest was excited and the world rang with the fame of Maury’s “Winds and Currents Charts.” Copies were sent to every government and distributed to men-of-war and merchantmen. It has been estimated that “if the money he saved to the world were collected, a monument of precious stones could be erected to his memory.” It was frequently urged that Maury, who was drawing a pay small in comparison to his service, might secure a copyright and thus reap material reward from his labors, but his aim through life had been to make himself of use to his fellow men, and he did not put in a claim for prize money. While at the observatory he wrote his “Physical Geography of the Sea and Its Meteorology.” This work met with great enthusiasm in England and America, and was translated into many languages for use in the schools. The interest now excited in meteorology and deep sea study enabled Maury to assemble at Brussels, under the auspices of King Leopold, a congress to which England, Russia, France, United States, Belgium and other countries interested in commerce, sent delegates. At the close of the congress Maury returned to America laden with honors and rich in fame. Many of the learned societies of Europe elected him an honorary member. Orders of knighthood were offered him and medals given him by nearly every crowned head of Europe. It is said that Humboldt received the Cosmos Medal as being the greatest scientist in the world, but he presented it to Maury as being greater than he, saying that he was the “founder of a new science.”