Originally Posted by Parabola
[Linked Image from i.imgur.com]

Here is a picture of the inside of the right hand lock of the Cogswell Gibbs and Pitt gun.

I think the number 1028 is a patent use number.

Note that the polish on the bottom of the mainspring suffices to act as a mirror after almost 140 years.

I thought at first that the intercepting safety sear was covered by Holland’s 1887 patent but as this gun dates from 1882 or thereabouts it must be part of an earlier patent.

The 'Block Patent Safety' exhibited by your gun has been attributed to Scott and Holland but it is neither. Even Baker & Crudgington got it wrong, misled by H&H's advertising muscle!
It is fact a reworking of the Needham & Hinton interceptor sears patent no. 706 of 1879 where the 'block' is part of the trigger blade but operates in exactly the same way. H&H showed it in the patent specification for patent no. 5834 of 1887 (operating as a separate piece of metal) but, as with many pre-invented mechanisms, they were wise enough to not put too much emphasis on the safety, concentrating on the ejector the patent covered.