We are aware that there may be inaccuracies in the foregoing estimates; but the compilers of the census, not we, are responsible for them. Besides, the figures are unquestionably as fair for the South as for the North; we accept them, therefore, as a just basis of our comparisons. Nearly seven years have elapsed since these statistics were taken, and these seven years have wrought an immense change in the journalism of the North, without any corresponding change in that of the South. It is noteworthy that, as a general thing, the principal journals of the free States are more comprehensive in their scope, more complete in every department, and enlist, if not a higher order of talent, at least _more_ talent, than they did seven years ago. This improvement extends not only to the metropolitan, but to the country papers also. In fact, the very highest literary ability, in finance, in political economy, in science, in statism, in law, in theology, in medicine, in the belles-lettres, is laid under contribution by the journals of the non-slaveholding States. This is true only to a very limited degree of Southern journals. Their position, with but few exceptions, is substantially the same that it was ten years ago. They are neither worse nor better--the imbecility and inertia which attaches to everything which slavery touches, clings to them now as tenaciously as it did when Henry A. Wise thanked God for the paucity of newspapers in the Old Dominion, and the platitudes of "Father" Ritchie were recognized as the political gospel of the South. They have not, so far as we can learn, increased materially in number, nor in the aggregate of their yearly circulation. In the free States no week passes that does not add to the number of their journals, and extend the circle of their readers and their influence. Since the census tables to which we have referred were prepared, two of the many excellent weekly journals of which the city of New-York can boast, have sprung into being, and attained an aggregate circulation more than twice as large as that of the entire newspaper press of Virginia in 1850--and exceeding, by some thousands, the aggregate circulation of the two hundred and fifty journals of which Alabama, Arkansas, Kentucky, Georgia, North Carolina and Florida, could boast at the time above-mentioned. In this connection, we beg leave to introduce the following letter, kindly furnished us by the proprietors of the N. Y. Tribune, in answer to enquiries which we addressed to them:-- TRIBUNE OFFICE, New York,} 30th May, 1857. } MR. H. R. HELPER, _Sir_:--