Professor Blackie is a man with whom we cannot be angry, however greatly his utterances are calculated to arouse that feeling. He is so impulsive, frank, and essentially good-natured, that even his most provoking words call forth rather a smile of compassion than a frown of resentment. Those who know his character and position will yield him the widest allowance. His fiery nature prompts him to energetic speech on all occasions. But when his temper has been fretted, as it frequently is, by the boisterous whims of his Greek students in that most boisterous of universities, it is not surprising if his expressions become splenetic even to rashness. The ingenuous Professor is quite impartial in his denunciations. He strikes out right and left against various objects of his dislike. Everything he dissents from receives one and the same kind of treatment, so that no opinion he assails has any special reason to complain; and every blow he deals is accompanied with such a jolly smile, sometimes verging into a hearty laugh, that no opponent can well refuse to shake hands with him when all is over. This temper, however, is somewhat inconsistent with the scientific purpose indicated in the title of Professor Blackie's book. A zoologist who had such a particular and unconquerable aversion to one species of animals that the bare mention of its name made his gorge rise, would naturally give us a very inadequate and unsatisfactory account of it. So, in this case, instead of getting a true natural history of Atheism, which would be of immense service to every thinker, we get only an emphatic statement of the authors' hatred of it under different aspects. Atheism is styled "a hollow absurdity," "that culmination of all speculative absurdities," "a disease of the speculative faculty," "a monstrous disease of the reasoning faculty," and so on. The chapter on "Its Specific Varieties and General Root" is significantly headed with that hackneyed declaration of the Psalmist, "The fool hath said in his heart, There is no God," as though impertinence were better from a Jew than from a Christian, or more respectable for being three thousand years old. Perhaps Professor Blackie has never heard of the sceptical critic who exonerated the Psalmist on the ground that he was speaking jocosely, and really meant that the man who said _in his heart_ only "There is no God," without saying so _openly_, was the fool. But this interpretation is as profane as the other is impertinent; and in fact does a great injustice to the Atheist, who has never been accustomed to say "There is no God," an assertion which involves the arrogance of infinite knowledge, since nothing less than that is requisite to prove an universal negative: but simply "I know not of such an existence," which is a modest statement intellectually and morally, and quite unlike the presumption of certain theologians who, as Mr. Arnold says, speak familiarly of God as though he were a man living in the next street.