This one???

>>The Purdey/Wyatt Patent No.4218 of 1818 blocked both the hammer and trigger. The 'Manton style,' to which
I previously referred, blocked the triggers. J.H. Walsh, author of The Sportsman's Gun and Rifle (1882)
credited Manton with the design - but there is no patent that supports his attribution. Additionally, Neal and
Back's definitive books on the Mantons make no such claim.

There were a number of designs available. The Purdey/Wyatt and the 'Manton style' used a long bar below the
trigger guard tang. The difference of their operation might not be apparent to a casual observer. Powell
used another design as well, that I can't link to a patent. It had a 1 1/4" by 1/4" rectangular piece that
substituted for the longer bar of other designs.

I have documented these safeties being installed on Powell guns as late as 1909. If you are familiar with the design
of the grip safety on a M1911 Colt - you'll note that it blocks the trigger in a manner similar to the "Manton style."

Not to be outdone, the Rossons (P.J. & C.S.) were granted Patent No.4883 in 1913 for a grip safety.<<