It is not be denied that Miss MARTINEAU is one of the cleverest women of our time; deafness and ugliness have induced her to cultivate to the utmost degree her intellectual faculties, and several of her books are illustrations of a mind even masculine in its power and activity; but the constitutional feebleness, waywardness, and wilfulness of woman is nevertheless not unfrequently evinced by her, and as she grows older the infirmities of her nature are more and more conspicuous; vexed with neglect, without the kindly influences of home or friendship, without the consolations or hopes of religion, she seems now ambitious of attention only, and willing to sacrifice every thing womanly or respectable to attract to herself the eyes of the world--the last thing, in her case, one would think desirable. In the book she has just published--_Letters on Man's Nature and Development, by Harriet Martineau and H. G. Atkinson_--she avows the most positive and shameless atheism: Christians have had little regard for Pagan deities--she will have as little for theirs! The sun rose yesterday; the fishes still swim in the sea; all the world goes on as before; but she cares not a fig for any deities, Christian or pagan--and don't believe a word of the immortality of the soul! In this new book, of which she is the chief author, the interlocutors place implicit credence in all the phenomena of mesmerism, and they cannot believe there is any thing in man's being or existence or conscience beyond what the senses reach, beyond what the scalpel discloses in the brain. They trace acts and motions and even inclinations to the brain, and deny that there is or can be any thing in contact which can influence it. _Cerebrum et praeterea nihil_ is their motto. The book is the apotheosis of that lump of marrow and fibre. And yet this brain, which is so jealously guarded from any spiritual or immaterial influence, is declared to be completely under the direction of any man or woman who may pass a hand, with faith, backwards and forwards over the skull. The extremities of the body--the fingers--send forth and radiate certain electric, or galvanic, or invisible influences, and thus one has full power over another's organization and volition! But as to any influence beyond the sensible world, that Miss Martineau stoutly denies. The following passage is not an uninteresting specimen of this foolish production: