page_title: Blue Hill Meteorological Observatory
section_title: The building
hierarchical_section_title: Blue Hill Meteorological Observatory / History / The building
caption_attribution_description: English: Great Blue Hill Weather Observatory, Milton, MA.
context_page_description: The Blue Hill Meteorological Observatory, also known as Great Blue Hill Weather Observatory, Blue Hill Weather Observatory, or simply the Blue Hill Observatory, in Milton, Massachusetts is the foremost structure associated with the history of weather observations in the United States. Located atop Great Blue Hill at the junction of Interstate 93 and Route 138 about 10 miles south of Boston, Massachusetts, it is home to the oldest continuous weather record in North America, and was the location of the earliest kite soundings of the atmosphere in North America in the 1890s, as well as the development of the radiosonde in the 1930s.
  Founded by Abbott Lawrence Rotch in 1884, the observatory took a leading role in the newly emerging science of meteorology and was the scene of many of the first scientific measurements of upper atmosphere weather conditions, using kites to carry weather instruments aloft. Knowledge of wind velocities, air temperature and relative humidity at various levels came into use as vital elements in weather prediction due to techniques developed at this site. By 1895 the observatory was the source of weather forecasts of remarkable accuracy.
context_section_description: Construction of the observatory was started by Rotch in 1884 using his own private funds, and designed by architects Rotch & Tilden.  The original structure consisted of a two-story circular tower and an adjoining housing unit which contained two bedrooms, a dining room and a kitchen.  In 1889, a two-story east wing was added to provide additional working space for research, domestic chores, and the library.  In 1902, a two-story west wing containing a new library was added to provide additional work space.  A steel fire door and brick wall connect the library to the earlier masonry structure.  A timbrel vault (18 by 35 ft) of cohesive tiles spans the library.  The timbrel vault tile roof is believed to have been installed by the Guastavino Company using an extremely tenacious mortar developed by Rafael Guastavino, the founder of the firm.
  Native stone, gathered from the summit of the Great Blue Hill, was used for the two-story tower, adjoining housing unit, and the east and west wings. Copper sheathing was used for roofing.  A stone wall and iron fence were erected in 1905 to provide security for the building and instruments and privacy for the staff.  The original stone tower eventually proved to be unsuitable. Wind-driven rain penetrated its walls, damaging the instruments and records. Vibration from the instruments on masts atop the tower contributed to the structural problems.
  In 1908, the original tower was demolished and a new reinforced three-story late Gothic Revival concrete tower, 20 feet 6 inches wide and 32 feet 8 inches high was constructed in its place.  The concrete construction of the tower was chosen specifically to provide the maximum amount of stability and durability in the event of high winds.  The tower has a crenelated top and a cornice containing dentils.  The windows are double-hung sash with a shallow recessed arch over the windows on the first and second floors.
  The new tower provided the durable weather-resistant, vibration-free environment necessary for accurate instrument readings.  The first floor of the tower contains the director's office.  The weather bureau is on the second floor and a laboratory and access to the roof are found on the third floor.  Various wind gauges and other meteorological recording instruments are attached to the roof of the tower.  The observatory still retains barometers and other instrumentation dating from the late 19th century.  These instruments are used to calibrate the modern instrumentation to preserve the accuracy and integrity of the data base dating back to 1885.
  In 1962, a metal tower containing a siderostat for collecting the sun's rays and directing them by mirrors to an optical bench inside the observatory, was erected adjacent to the west wing for studies related to the upper atmosphere.  This project was abandoned after a few years.  This tower, with its mirrors still present, is no longer in use.
  The observatory has been neglected for a number of years. Although the structure is generally weather-tight, due to both solid construction and a copper roof, the reinforced concrete tower is plagued by the elements. The frost-thaw cycle has caused some cracking and spalling of the concrete.
  In 1980, the building was listed in the National Register of Historic Places as "Great Blue Hill Weather Observatory", as part of a multiple property nomination by the Commonwealth of Massachusetts entitled "Prehistoric and Historic Resources of the Blue Hills and Neponset River Reservations and Selected Adjacent Lands".
  In 1981, the Metropolitan District Commission transferred responsibility for the observatory to the Blue Hill Weather Club, a local group of supporters, who plan to restore the observatory and establish a weather museum on the site. The observatory will be kept open to continue its record of continuous weather observations. The National Weather Service continues to operate an Automated Surface Observing System at the site.
  A white marble stone containing a summary record of climatological data from 1885 to 1984 and dedicated to the memory of Abbott 
caption: View from the west-northwest
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