The original announcement called it "Colt's New Double Action Self Cocking Central Fire, Six Shot Revolver." It also says, "The pistol should be carried with the hammer resting in the safety-notch."
The "Model 1878" (sometimes called the Double Action Army) is called in a catalog "Colt's New Double Action, Self-Cocking, Central Fire, Army, Six Shot, .45 Inch Calibre, Revolving Pistol."
One can imagine the sheriff shouting, "Stop or I will draw my Colt's New Double Action, Self-Cocking, Central Fire, Army, Six Shot, .45 Inch Calibre, Revolving Pistol and shoot." Ah, the good old days!
Jim