Christian by descent, a philosopher, and an honoured attendant at the Court of the Caliph Al Māmūn, must add prodigiously to the weight that necessarily attaches, from its intrinsic merits, to our author's argument. Between this and Pfander's works, there is just the difference between perusing an essay, and listening to the warm and impassioned eloquence of the advocate in his own defence; between reading the description of a battle, and witnessing with your own eyes the hotly-contested field of battle itself,
