Now the mountain ranges and table lands of Mexico are not thus supplied with moisture. For the space of four months in Southern and less in Northern Mexico, and in summer, and while the belt of the tropics is extended up over them, they have rain and in daily showers which _travel up from the south_, indicating the course of the counter-trade. (See Bartlett's Personal Narrative, vol. ii. p. 286.) At other seasons, and while we are bountifully supplied, they are dry. In short, there are no two portions of the earth that differ more widely in regard to their supply of moisture, and all their climatic characteristics and relations. It is therefore, according to all analogy, impossible that our counter-trade should come from the South Pacific across the continent and below 35 deg., and in this also those gentlemen are mistaken. Messrs. Espy and Redfield recognizing the existence of "a prevailing" S. W. current, but considering the surface-winds beneath it as the principal actors in producing the atmospherical conditions and changes, have attributed no office to that current, except that of giving direction and progression to our storms. This is their great mistake. It plays no such unimportant part in the philosophy of the weather, as we have already incidentally seen, and will proceed still further to consider. _All our storms originate in it._ This we may know from analogy. _Where there is no counter-trade, outside of the equatorial belt of rains, and within influential distance of the earth, there are neither storms nor rain._ So, when, as we have seen, the concentration of the volume of northern counter-trade in the West Indies, gathered by the hauling of the S. E. trades more from the east, as they approach the central belt, diminishing the volume of the counter-trade over the North Atlantic, the calms and drought of the horse-latitudes are found. And when the counter-trade is small in volume and weak in intensity, by reason of the fact that the surface-trades from the opposite hemisphere which constitute it, formed upon land where evaporation was small, as upon Southern Africa and New Holland, or formed where the magnetic intensity was weak, or passed over mountain ranges in their course, the annual supply of rain, the ranges of the barometer, and the alternations of atmospheres conditions are remarkably less.