This is a Charles Horner, Chester sterling silver thimble with a steel interior for extra strength from around 1884/89 . A Dorcas patent was taken out in 1884 for a thimble with a steel core encased in sterling silver to overcome the problem of holes caused by needles in the soft silver. The first ones were marked PAT 7 and were not allowed to be marked silver because of the steel core. A second patent was taken out in 1889 and these were marked Dorcas CH and the size no. This thimble is in the first group and is sterling silver encasing a steel core.
 
The thimble is in good antique condition, the rim is undamaged and round.  There are 2 small pin holes to each side.  Age related wear, please see photos
 
 H. 2.5 cm  D. 1.8 cm