Most of the regulars then returned to Boston the way they had come, but a small contingent marched on to Cambridge, seizing two field pieces from the Cambridge Common. The field pieces and powder were then taken from Boston to the British stronghold on Castle Island, then known as Castle William (renamed Fort Independence in 1779). In response to the raid, amid rumors that blood had been shed, alarm spread through the countryside as far as Connecticut and beyond, and American Patriots sprang into action, fearing that war was at hand. Thousands of militiamen began streaming toward Boston and Cambridge, and mob action forced Loyalists and some government officials to flee to the protection of the British Army. This action provided a "dress rehearsal" for the Battles of Lexington and Concord seven months later in the famous "shot heard 'round the world". This did however, inflame already heated feelings on both sides and would spur actions by both British and American forces to secure both powder and cannon to secure locations. Massachusetts began storing gunpowder elsewhere and sold the land containing the Powder House to Peter Tufts in 1818. The estate, known as the Powder House Farm, was used as a farm and residence for the Tufts family for most of the 19th century, passing to Peter's heir, Nathan Tufts. Incidentally, another Tufts relative Charles Tufts donated the land across Broadway on the Somerville/Medford line to found Tufts College (now Tufts University). The college was founded in 1852, on Walnut Hill slightly to the north of present-day Powder House Square. In the 1870s, a pickle and condiment manufacturer named George Emerson began making pickles nearby, housing his business in a large shed that he moved to the property from another location in Somerville. The powder house itself, with its two-foot thick stone walls, was well-insulated and made a perfect place for storing Emerson's "Old Powder House Brand" pickles. The descendants of Nathan Tufts donated the Powder House Farm along with its namesake structure to the city in 1890, and from this Nathan Tufts Park was established in 1893. The Field House was constructed in 1935-36 using stones from the 1934-demolished Somerville Highlands railroad station, which had closed in 1927 when passenger service on the Fitchburg Cutoff ended. Sponsored by the Federal Relief Administration as a Work Projects Administration Project, it has served many purposes over the years, including as an office for the Draft Board, then for the Traffic and Parking Department, and most recently as a Youth Program center.