Within the city of Chihuahua, metropolis of the northern provinces of Mexico-for the most part built of mud-standing in the midst of vast barren plains, o'ertopped by bold porphyritic mountains-plains with a population sparse as their timber-in the old city of Chihuahua lies the first scene of our story. Less than twenty thousand people dwell within the walls of this North Mexican metropolis, and in the country surrounding it a like limited number.