Tisdall patent 2177 of 1879 is illustrated on page 121 of Vol,2 of," The British Shotgun",by Crudgington and Baker.The patent refers to a safety slide comprising a square bolt that slides from side to side through the lock plates.In this patent the safety slide could be worked by the Scott Top lever spindle.If your gun incorporates this patent,I am sure many viewing this forum would appreciate your posting pictures of your gun.

Roy Hebbes