Regarding single triggers:
"Thorn's (Lancaster) patent No. 5517 for "Improvements in Single Trigger Guns" was sealed on 18 January, 1896.
The issue of "The Field" dated 1st June, 1895 had an expose on the patent entitled "Lancaster's One-Trigger Double Gun". Hence, although single triggers were first patented in 1789 and 1791, the first, safe, credible single trigger was the one created by Thorn. (Lancaster)
**I might add to all of this that it was very common for Lancaster's best guns to be proofed for 1-1/8 or even 1-1/4 ounce loads, making single trigger systems the more difficult to prevent double-discharge due to recoil. (it was a marketing ploy by Thorn to demonstrate confidence in his system)
My notes also show a second reference patent by James Smallman No. 13492 of 1896. Both this patent and the aforementioned one above were referenced in Lancaster's third patent of 28 January, 1904 No. 7046. (that patented system appears to have required less inletting)
