This discovery made a great sensation in the scientific world. Franklin at once became famous, took high rank as a man of science, and was afterwards known as "Doctor Franklin." He now invented the lightning rod, which has been in use ever since all over the civilized world. =259. Entrance into a Broader Public Life.=--From this time Franklin began to occupy more important positions in public life. In 1754 he was sent on a mission to Albany to enlist the chiefs of the powerful "Six Nations" to become allies of the English. On this journey he drew up a plan for the union of the colonies. It was almost like that by which they were afterwards bound together as a nation. During the Braddock campaign Franklin in vain warned the haughty British general that "the Indians would surprise, on its flanks, the slender line, nearly four miles long, which the army must make," and would "cut it like a thread into several pieces." From his own purse Franklin advanced for this ill-starred expedition between six and seven thousand silver dollars. The quarrels between the Pennsylvania Assembly and the Proprietors in England became so bitter that Franklin was sent to England in 1757 as the sole commissioner to make an appeal to the English government. He was cordially received abroad and highly honored by the most eminent scientific men of the time. He returned home after an absence of nearly six years. Franklin was now fifty-seven years old. He had an ample fortune, perfect health, and a superiority to most men in personal appearance and dignity. He hoped to withdraw from public life and give the rest of his days to the study of science. =260. Franklin becomes a most Useful and Sagacious Helper to the Struggling Colonies.=--Great and momentous events, however, were at hand. There was more important work for him to do. The struggling colonies, already taxed almost beyond endurance to carry on the war against the French and Indians, were allowed no representation nor voice in the matter of taxation. Franklin, with patriotic foresight and with keen force of logic, resisted the outrage. He declared it to be the "mother of mischief." In 1764 Franklin was again sent by the Assembly to England, to present to the British court the protest of the people against "taxation without representation." [Illustration: FRANKLIN AT THE COURT OF FRANCE.] From this time Franklin served the colonies in England as a most accomplished diplomatist, a vigorous writer, and a shrewd and sagacious agent. He failed to stop the passage of the notorious Stamp Act, but he fought the measure so vigorously by his writings and discussions that he aroused bitter opposition to it among the industrial classes, so that Parliament was compelled at last to repeal the obnoxious measure. He was once brought before the House of Parliament and sharply questioned. "Do you think," asked the prime minister, "the people of America would submit to pay the stamp duty if it was changed?"