From the time of his leaving school till the latter part of 1753, Washington was unconsciously preparing himself for the great duties he had afterward to discharge. An attempt made to have him entered in the Royal Navy, in 1746, was frustrated by the interposition of his mother. The winter of 1748-49 he passed at Mount Vernon, then the seat of his brother Lawrence, in the study of mathematics and the exercise of practical surveying. George was introduced about this time to the family of Lord Fairfax, his brother having married the daughter of William Fairfax, a member of the Colonial Council, and a distant relative of that nobleman. The immense tracts of wild lands belonging to Lord Fairfax, in the valley of the Alleghany Mountains, had never been surveyed; he had formed a favorable estimate of the talents of young Washington, and intrusted the task to him. His first essay was on some lands situated on the south branch of the Potomac, seventy miles above its junction with the main branch. Although performed in an almost impenetrable country, while winter yet lingered in the valleys, by a youth who had only a month before completed his sixteenth year, it gave so much satisfaction that he soon after received a commission as public surveyor, an appointment which gave authority to his surveys, and enabled him to enter them in the county offices. The next three years were devoted without intermission, except in the winter months, to his profession. There were few surveyors in Virginia, and the demand for their services was consequently great, and their remuneration ample. Washington spent a considerable portion of these three years among the Alleghanies. The exposures and hardships of the wilderness could be endured only for a few weeks together, and he recruited his strength by surveying, at intervals, tracts and farms in the settled districts. Even at that early age his regular habits enabled him to acquire some property; and his probity and business talent obtained for him the confidence of the leading men of the colony.