Jeffrey Lock Discusses Surveying Instruments at Lunch & Learn

Mr. Lock shows attendees the fine details of antique surveying instruments.

Yesterday afternoon, the Germantown Historical Society welcomed back Jeffrey Lock to lead a Lunch & Learn to discuss his restoration of the Rittenhouse Compass over the past year. Last May, after its restoration was complete, the compass made its journey back to the Germantown Historical Society. “Do I need to give this some Dramamine?” Lock questioned with a smile, as he prepared the 18th century compass for its first ever plane flight.

The David Rittenhouse Compass has been in the collections of the Germantown Historical Society since 1910. After seeing that the compass had undergone a poor polishing job in the early 20th century, Mr. Lock offered to restore the compass and protect it with a conservation wax that would allow it to age gently.

Antique manuscript, compasses, and surveying chain

In a presentation, Mr. Lock shared his awe and appreciation for the fine engraving and craftsmanship of the David Rittenhouse Compass as well as related antique surveying instruments. According to Mr. Lock, a complete compass would take a regular maker a minimum of three weeks and would sell for about seven pounds. These instruments, however, were not simply made for show. They were heavily used as America surveyed its expanding borders. The instruments have stood the test of time as they still prove to be accurate in readings of magnetic North.

Read more about Mr. Lock’s work including his conservation of the Rittenhouse Compass here.

There are, according to Mr. Lock, only about a dozen known Rittenhouse compasses. The Germantown Historical Society is very fortunate to have one of these beautiful instruments from one of the finest colonial compass-makers.

Keep your eye out for future Lunch & Learn opportunities.