London, Tuesday, July 22, 1851.

The quickest and most usual route from Paris to London is that by way of Calais and Dover; but as I had traversed that once, and part of it twice, I resolved to try another for my return, and chose the cheapest and most direct of all—that by way of Rouen, Dieppe, New-Haven and the Brighton Railroad—which is 32 miles shorter than the Calais route, but involves four times as long a water passage, and so is spun out to more than twice the length of the other. We left Paris at 8 yesterday morning; halted at the fine old town of Rouen before noon; were in Dieppe at 2½ P. M.; but there we waited for a boat till after 6; then were eight hours crossing the Channel; had to wait at New-Haven till after 6 this morning before the Custom-House scrutiny of our baggage was begun; so that only a few were enabled to take the first train thence for London at a quarter to 7. I was not among the lucky ones, but had to hold on for the second train at a quarter past 8, and so did not reach this city till after 10, or twenty-six hours from Paris, though, with a little enterprise and a decent boat on the Channel, the trip could easily be made in 14 hours—four for the French side, six for the Channel, two for the English side and two for Custom-House delay and leeway of all kinds. If Commodore Vanderbilt or Mr. Newton would only take compassion on the ignorance and barbarism prevailing throughout Europe in the matter of steamboat-building, and establish a branch of his business on this side of the Atlantic, he would do the cause of Human Progress a service, and signally contribute to the diminution of the sum of mortal misery.

The night was mild and fair; the wind light; the sea consequently smooth; and I suffered less, and repented my choice of a route less, than I had expected to; but consider the facts: Here was the most direct route by Railroad and Steamboat between the two great Capitals of Europe—a route constantly traveled by multitudes from all parts of world—yet the only boats provided for the liquid portion of the way are two little black, cobbling concerns, each perhaps seventy feet long by fifteen wide, with no deck above the water line, and not a single berth for even a lady passenger, though making one passage each night. Who could suppose that two tolerably civilized nations would endure this in the middle of 1851?

We were nearly two hundred passengers, and the boat just about decently held us, but had not sitting-room for all, above and under the deck. But as about half, being "second class," had no right to enter the main cabin, those who had that right were enabled to sit and yawn, and try to cheat themselves into the notion that they would coax sleep to their aid after a while. Occasionally, one or two having left for a turn on deck, some drowsy mortal would stretch himself on a setter at full length, but the remonstrances of others needing seats would soon compel him to resume a half-upright posture. And so the passage wore away, and between 2 and 3 this morning we reached New-Haven (a petty sea-port at the mouth of the little river Ouse), where we were permitted promptly to land, minus our baggage, and repair to a convenient inn. Here I, with several others, invested two British shillings in a chance to sleep, but the venture (at least in my case) proved a losing one. It was daylight when we went to bed, and the incessant tramping, ringing of bells, &c., kept us for the most part awake and called us up at a very early hour, to fidget uselessly for the recovery of our baggage, and lose the early train at last.

The country stretching north-westward from Paris to Dieppe (125 miles) is less thoroughly cultivated than any other I have seen in Europe out of Italy. I saw more weedy and thin Rye and ragged Wheat than I had noted elsewhere. Grass is the chief staple, after leaving the garden-covered vicinity of Paris, though Wheat, Rye and Oats are extensively cultivated. The Root crops promise poorly. Indian Corn is hardly seen, though the Vine is considerably grown. This region is generally well wooded, but in a straggling, accidental way, which has the effect neither of Lombard nicety of plantation, nor of the natural luxuriance of genuine forests. Fruit is not abundant. Irrigation is considerably practiced. The dwellings of the majority have an antiquated, ruinous, tumble-down aspect, such as I have observed nowhere else this side of Lower Italy. On the whole, I doubt whether this portion of France has improved much within the last fifty years.

Rouen, the capital of ancient Normandy, is the fifth city of France, only Paris, Lyons, Marseilles and Bordeaux having more inhabitants. Here the Railroad for Havre diverges from that to Dieppe, which we adhered to. Rouen is interesting for its antiquities, including several venerable and richly adorned Churches which I had no time to visit. Dieppe, on the Channel, has a small harbor, completely landlocked, and 17,000 inhabitants. It is considerably resorted to for sea-bathing, but seems to have very little trade. I judge that the Railroads now being extended through France, are likely to arrest the growth or hasten the decline of most of the smaller cities and towns by facilitating and cheapening access to the capital, where nearly every Frenchman would live if he could, and where the genius of people and government (no matter under what constitution) conspires to concentrate all the intellectual and artistic life of the Nation.

The Railroad from New-Haven to London passes through no considerable town, though not far from Brighton and Tunbridge. The country is undulating and beautiful, mainly devoted to Grass, Wheat and Wood, and in the very highest condition. It is now toward the end of Haying, and the Wheat is just beginning to ripen, though that of Central Italy was mainly harvested a full month ago. But the English Wheat covers the ground thickly and evenly, and promises a large average crop, especially if the present fine weather should continue through the next two weeks.

Noble herds of Cattle and flocks of Sheep overspread the spacious grounds devoted to Pasturage, especially near the Channel, where most of the land is in Grass. English Agriculture has a thorough and cleanly aspect which I have rarely observed elsewhere. Belgium is as careful and as productive, but its alternations of tillage or grass with woodland are by no means so frequent nor so picturesque as I see here. The sturdy, hospitable trees of an English park or lawn are not rivaled, so far as I have seen, on the Continent. I have rarely seen a reach of country better disposed for effect than that from a point ten miles this side of New-Haven to within some ten miles of this city, where Market Gardening supplants regular Farming. Women work in the fields at this season in England, but not more than one woman to five men were visible in the hay-fields we passed this morning—it may have been otherwise in the afternoon. As to beggars, none were visible, begging being disallowed.

Crossing the Channel shifts the boot very decidedly with respect to language. Those who were groping in the dark a few hours ago are now in the brightest sunshine, while the oracles of yesterday are the meekest disciples to-day. I rode from New-Haven to London in the same car with three Frenchmen and two Frenchwomen, coming up to the Exhibition, with a scant half-allowance of English among them; and their efforts to understand the signs, &c., were interesting. "London Stout," displayed in three-foot letters across the front of a drinking-house, arrested their attention: "Stoot? Stoot?" queried one of them; but the rest were as much in the dark as he, and I was as deficient in French as they in English. The befogged one pulled out his dictionary and read over and over all the French synonyms of "Stout," but this only increased his perplexity. "Stout" signified "robust," "hearty," "vigorous," "resolute," &c., but what then could "London Stout" be? He closed his book at length in despair and resumed his observations.

LONDON AT MIDNIGHT.

London is given to late hours. At 6 A. M. though the sun has long been up, there are few stirring in the principal streets; occasionally you meet a cab hurrying with some passenger to take an early train; but few shutters are down at 7, and scarcely an omnibus is to be seen till after 8. The aristocratic dinner hour is 8 P. M. though I trust few are so unmerciful to themselves as to postpone their chief meal to that late hour when they have no company. The morning to sleep, the afternoon to business and the evening to enjoyment, seems the usual routine with the favored classes.

Walking home from a soirÉe at the West-end through Regent-street, Haymarket and the Strand once at midnight, I was struck, though accustomed to all manner of late hours in New-York, with the relative activity and wide-awake aspect of London at that hour. It seemed the High Change of revelry and pleasure-seeking. The taverns, the clubs and drinking-shops betrayed no symptoms of drowsiness; the theatres were barely beginning to emit their jaded multitudes; the cabs and private carriages were more plentiful than by day, and were briskly wheeling hundreds from party to party; even the omnibuses rattled down the wide streets as freshly and almost as numerously as at midday. The policemen were alert on nearly every corner; sharpers and suspicious characters stepped nimbly about the cross-streets in quest of prey, and innumerable wrecks of Womanhood, God pity them! shed a deeper darkness over the shaded and dusky lanes and byways whence they momently emerged to salute the passer-by. Beneath the shelter of night, Misery stole forth from its squalid lair, no longer awed by the Police, to beseech the compassion of the stranger and pour its tale of woe and suffering into the rarely willing ear. Serene and silvery in the clear night-air rose the nearly full moon over Southwark, shedding a soft and mellow light on pillar and edifice, column and spire, and enduing the placid bosom of the Thames with a tranquil and spiritual beauty. Such was one glimpse of London at midnight; I have not seen it so impressive by day.