Between 1870 and 1915, Milton grew into the community it is now: a streetcar suburb with some chocolates, biscuits, and market produce to remind residents of the past. By 1929, many of the big estates were broken into subdivisions as the town's residential growth continued. The Suffolk Resolves were signed in Milton in 1774, and were used as a model by the drafters of the Declaration of Independence in 1776. The Suffolk Resolves House, where the Resolves were passed, still stands and it is maintained as the headquarters of the Milton Historical Society. The house was moved to a new location at 1370 Canton Avenue in West Milton in order to save it from demolition at its previous location in "Milton Village" at Lower Mills. They were the "Suffolk Resolves" because Milton was part of Suffolk County until 1793, when Norfolk County split off, leaving only Boston and Chelsea in Suffolk County. Two royal governors of Massachusetts, Jonathan Belcher and Thomas Hutchinson, had houses in Milton. The Governor Belcher House dates from 1777, replacing the earlier home destroyed in fire in 1776, and it is privately owned on Governor Belcher Lane in East Milton. Although Hutchinson's house was demolished in the 1940s, Governor Hutchinson's Field, owned by the Trustees of Reservations today is a wide expanse of greenery on Milton Hill, with a view of the Neponset River estuary and the skyscrapers of Boston six miles (10 km) away. Both Governor Belcher's house and Governor Hutchinson's field are on the National Register of Historic Places. The town was home to America's first piano factory. Revolutionary Milton is the setting of the opening of the 1940 bestselling historical novel "Oliver Wiswell" by Kenneth Roberts. The Blue Hill Meteorological Observatory is located in the town, home of the nation's oldest continuously kept meteorological records. The Granite Railway passed from Quincy to the Neponset River in Milton, beginning in 1826. It is often called the first commercial railroad in the United States, as it was the first chartered railway to evolve into a common carrier without an intervening closure. A centennial historic plaque from 1926 and an original switch frog and section of track from the railway can be found in the gardens on top of the Southeast Expressway (Interstate 93) as it passes under East Milton Square. The frog had been displayed at the Chicago World's Fair in 1893. East Milton Square developed as a direct result of the Granite Railway.