It will be enough to advert very briefly to the Mohammedan imposture, though that is perhaps the most signal instance within all time, of a malignant delusion maintained directly and immediately by ignorance, by an absolute determination and even a fanatic zeal not to receive one new idea. Tenets involving the most palpable impossibilities, and asserted in self-contradictory terms, must stand inviolable to all question or controversy; literature must be scouted as a profane folly; not a principle of true philosophy is to be admitted; hardly is an application of the plainest mechanics to improve a machine or implement to be tolerated; or an infidel is to be only _pardoned_, through contempt, for a successful obtrusion of science to render the most important service,--to save, for instance, a Mussulman ship-with its proud, besotted commander and crew from destruction, [Footnote: There is a very curious example of this related in Dr Clarke's Travels.] lest an acknowledgment made to science should allow one momentary surmise of imperfection to insult the all-sufficiency and sanctity of the unalterable creed and institutes; lest any diminutive crevice should be made on any side of the temple of the vile superstition, for the passage of one glimpse of true light to annoy the foul fiend that dwells there, invested "in the dunnest smoke of hell." Not, however, that this is the policy of doubt and apprehension, the evading and repelling caution of men who suspect themselves to be wrong and dread being forced to meet the proof. For the subjects of this execrable usurpation on the human understanding have, in general, the firmest assurance that all things in the system are right: it has itself secured them against _knowing_ anything that could discompose their sense of certainty. No fell savage, or serpent, or monster, ever had a more perfect instinct to avail itself of an impervious obscurity for its lurking-place, than this imposture has shown to keep out all mental light from its realm. The delusion is so strong and absolute in ignorance, is so identified with it, and so systematically repels at all points the approach of knowledge, that it is difficult to conceive a mode of its extermination that shall not involve some fearful destruction, in the most literal sense, of the people whom it possesses. And such a catastrophe it is probable the great body of them, in the temper of mind prevailing among them at this hour, would choose to incur by preference, we do not say to a serious, patient consideration of the true religion, but even to the admission among them of a system merely favoring knowledge in general, an order of measures which should urge upon the adults, and peremptorily enforce for the children, a discipline of intellectual improvement. There would be little national hesitation of choice, (at least in the central regions of the dominion of this hateful imposture,) between the