The Observatory on Tin-top Hill

Brown University is located in the College Hill neighborhood on the East Side of Providence. Ladd Observatory is a short distance to the north on one of the highest points in the area, a site that was once referred to as Tin-top Hill.

Anecdotes describing the origin of this name are frequently given. For example, a recent article in the Providence Journal states that "Before the observatory was built in 1891, this land was known as Tin Top Hill because it was a dumping ground for tin cans."

However, the name may have more to do with a carefully placed, but misunderstood and then forgotten, surveying aid.

Image: US Geological Survey, 26 April 2002    Click on image to see full resolution  [25 cm / pixel]

Surveying on the Summit

The elevation of this hilltop has attracted the attention of surveyors for many years. On the Observatory lawn there is a marker that is used as a surveying reference, or control point. It consists of a small metal disk embedded in concrete. The marker is designated OBSERVER 1968 and it was installed by the Coast and Geodetic Survey. The latitude and longitude of this marker are known to a high degree of precision. Markers such as this are used by surveyors to establish the coordinates of other nearby points using triangulation. The detailed description and history of this marker can be found in the National Geodetic Survey Datasheet for OBSERVER 1968 [PID LW2682]

The Tin Cone in a Tree

There are records of an earlier marker at this site designated COLLEGE HILL 1835. There was an attempt to recover the position of this marker in 1935 by the Rhode Island Geodetic Survey. A task made more difficult by the fact that "Neither the location nor the marking of this station is given..." The surveyors documented the area where the marker was thought to be located. They also interviewed people who lived nearby. The results of this investigation were included in their report:

"The geographic position is that of the more northeasterly of two summits of the hill lying between the Providence and Seekonk rivers. This summit is near the intersection of Hope Street and Doyle Avenue. If in existence in 1835, Hope Street was a rough country road known as East Pawtucket Turnpike. Doyle Avenue was not laid out until many years later. On this summit stands Ladd Astronomical Observatory of Brown University erected in 1891."

"This summit is locally known as Tin-top. Four independent sources agree that this name came from a bright piece of tin, conical in shape, hung in a very high oak tree and used as a sight by navigators and surveyors. Two ladies state that they remember a platform in this tree. John E. Canning states that the tree was cut down in 1907 at the time that his residence was built at 205 Doyle Avenue. Neither he nor the contractor who built his house can recall finding a buried marker, nor can they remember what became of the tin cone."

The most probable position of the missing marker was eventually established. However, "Digging a hole 3 feet deep at this point failed to reveal any clue." They concluded that "The station is lost and probably destroyed."
The former location of the marker is indicated in the image.
Image: US Geological Survey, 29 March 1995
Click on image to see full resolution  [100 cm / pixel]

Source of above quotes: Datasheet for COLLEGE HILL 1835 [PID LW2679]

Although the station marker was never located the information learned about the tin cone provides an interesting glimpse into the techniques used during the 19th century by surveyors working in this area. It also reveals that there is more to the origin of the hill's name than the anecdotes suggest. A hint to this origin can be seen in a descriptive detail found in the Ladd Observatory entry in Encyclopedia Brunoniana:

"The site chosen was an elevation about a mile from the University known as Tin-top Hill for its use as a depository for old tin cans which, reflected in the sunlight, could be seen from a distance."

Copyright © 2005 by Michael L. Umbricht
Last modified: 12:44 Mar. 01, 2005

http://physics.brown.edu/physics/commonpages/ladd/history/tintop.shtml