The lock project began with a request to assist with determining the age and conservation of a severely corroded iron rim lock found during renovation of an historic house at the Smithsonian’s Environmental Research Center. X-radiography revealed a large rectangular sliding bolt and quarter-round pivoting latch with up-and-down movement (extended at left), as well as a smaller square night bolt moved by a slide (bottom left). XRF analysis confirmed that a medallion at upper left center adjacent to the hub for the handle was made of brass. The medallion appeared to have lettering and decoration, and after a proposal for cleaning was approved, removal of corrosion revealed an inscription identifying it as a patent seal made by Carpenter & Co. in Wolverhampton, England, in 1830 or later based on the year that the patent was granted. Further investigation in the house found that the lock had been installed during its 1841 construction, where it was employed on a second-floor bedroom, probably that of the son of the owner. A recommendation was made that the lock not receive further conservation treatment, because corrosion appears to be keeping it intact; rather, storage or display in a container dried with silica gel was recommended to avoid further deterioration.

For more information, please see Examination and Treatment Report for a Carpenter & Co. Lock Found at SERC: Museum Conservation Institute #6955.