AS we are very liable, in common with the letter‑writing world, to fall behind‑hand in our correspondence; and a little more liable because in consequence of our editorial function we receive more epistles than our individual share, we have thought that we might clear our account by writing a quarterly catholic letter to all and several who have honored us, in verse or prose, with their confidence, and expressed a curiosity to know our opinion. We shall be compelled to dispose very rapidly of quite miscellaneous topics.
     And first, in regard to the writer who has given us his speculations on Railroads and Air‑roads, our correspondent shall have his own way. To the railway, we must say, — like the courageous lord mayor at his first hunting, when told the hare was coming, — “Let it come, in Heaven’s name, I am not afraid on ‘t.” Very unlooked‑for political and social effects of the iron road are fast appearing. It will require an expansion of the police of the old world. When a railroad train shoots through Europe every day from Brussels to Vienna, from Vienna to Constantinople, it cannot stop every twenty or thirty miles at a German custom‑house, for examination of property and passports. But when our correspondent proceeds to flying‑machines, we have no longer the smallest taper‑light of credible information and experience left, and must speak on a priori grounds.