From the fact that the current of foreign travel has been turned towards the capital of Mexico, by the way of Jalapa and Perote, and also from the further fact that the very _limited amount of American_ knowledge of Mexico is associated with the line of operations of the American army during the late war, less is publicly or _correctly_ known of our lower, or more southern route, than of the upper or northern route. The lower and shorter route presents the facilities of being six hours shorter to Puebla, and of having lower grades, and a climate unequalled for healthfulness, salubrity, and intertropical luxuriance of productions. There are features about the roads of Mexico generally that distinguish them from our northern roads; they are not muddy, having no frosts to produce periodic deterioration; they are only slightly disturbed during the rainy months of June, July, and August. The rains during these rainy months are not continuous, all-day rains, but fall in showers seldom longer than an hour, generally in the afternoons and at night, and the intervals between these showers are unclouded and salubrious. The whole geological formation of Mexico is eccentric, and the soil generally composed of the debris of matter of volcanic origin. Such materials form the best roads, and with an exemption from frosts, dust, mud, and rain, except in the rainy seasons, and with no fences to obstruct the facilities for turnpike, road-making, and travelling, presented in this part of Mexico, are unequalled. It should be remembered that this company are not encumbered with the necessity of enormous expenditures for making canals, building railroads and plank-roads, to develop their resources; they have only to expend under $50,000 to make one of the finest roads in the finest climate of North America, to travel smoothly and pleasantly, at the rate of seven and ten miles per hour, from the Atlantic to the Pacific ocean. From the certificate of Mr. Blumenkron, (see Appendix A,) a gentleman intimately acquainted with the whole route from personal observation, it will be seen that the facilities for the transportation of mails and passengers across the republic is the work of but little effort and expense; and from the extracts of Colonel Ramsey’s letter, (see Appendix B,) it will be seen what has actually been done. From these statements—and they are daily corroborated by Americans and Mexicans who have passed over the route—it appears that the mails have been carried over (at the worst of all seasons, the rainy ones) in 50, 60, 70, 80, and 81 hours; that the letter of Mr. Tyler announces their arrival at Acapulco in six days from New Orleans, and that the mail time across may be reduced to 48 hours, and passenger time to 54.