The death of his younger brother, however, altered Edward's destination, and caused him to be placed with his brother John, at that time a chamber master, employed chiefly in dividing and engraving for the trade, and the higher branches of the art. Under the instruction of John, who was an excellent workman, Troughton made very rapid progress, and at the end of his time was taken into partnership. About the year 1782 the Troughtons established themselves in Fleet Street, where they commenced an independent business and soon rose into eminence. After the death of his brother John, Edward alone continued the business until the year 1826, when increasing age and dislike to routine employment, induced him to take Mr. William Simms as his partner and successor. The instruments which facilitate navigation were peculiarly objects of interest to Mr. Troughton, and long after his infirmities were an effectual bar to the applications of his most esteemed friends, he exerted himself to supply the seamen with well adjusted and accurate sextants. "Your fancies," he would say, "may wait; their necessities cannot." In 1778 he took out a patent for the double framed sextant, a construction which, combining firmness and lightness, yet admitted of a considerable radius in this invaluable instrument. After trying and rejecting the repeating reflecting circle of Borda, Mr. Troughton, in 1796, hit upon one of his happiest constructions, the British reflecting circle, as he delighted to call it, an instrument which in right hands is capable of wonderful accuracy. It is a characteristic trait of Mr. Troughton, that in order to bring his favourite circle into general use, he reduced its price far below the usual profits of trade; and if he had succeeded in his attempt, he might have been ruined by his success, for his sextants were by far the most gainful article of his business. With the same earnestness to promote the interests of navigation, he invented the dip sector (afterwards re-invented by Dr. Wollaston), and expended time, money, and ingenuity to no inconsiderable amount, in attempting to perfect the marine top for producing a true horizontal reflecting surface at sea. The marine barometer, the snuff-box sextant, and the portable universal dial, owe to him all their elegance, and much of their accuracy. Where others invented or sketched he perfected.