The southerly winds, and those having a slight westerly tendency, prevailing a portion of the summer, do not bring hither much of moisture, though at their outset they are heavily ladened with it, as it is borne across the Gulf, in a southwesterly direction, to the open valley of the Mississippi, where, coming in contact with the edge of the great westerly winds, and broken probably somewhat by the elevated district of Mexico and by the foot-hills of the Rocky Mountains, which extend to the northern boundaries of Texas, this humid wind drives, unresisted by any vertical obstruction, up the valley of the “Great River,” shedding on either hand its waters profusely; but their force and character, in this long march, become spent, and they add only their proportionate amount of rain to the Minnesota annual fall, while the intermediate districts are chiefly dependent on them.

The northeast winds of spring and autumn, which sweep at times half across the continent, usually begin at a low point along the Atlantic coast—­driving sometimes furiously, and always persistently, its hurried, chilling current inland,—­is baffled by this southwesterly current of the Gulf, and always, sooner or later, turned, as it moves up the coast and interior by the overpowering and underlying continental winds which drive it back, bringing these northeasterly storms to us, nearly always from a southwest quarter.  We enlarge upon this class of rain-storms for the purpose of showing, though imperfectly, their non-prevalence over the State of Minnesota.  This is important if it can be, even but partially, established; since it is this particular class of storms and winds, last referred to, that are to be so much avoided and to which can be traced the initial point of most pulmonic troubles.

These storms from the northeast may begin in Texas, their course being north and eastward; as that by the time they reach so northerly a point as New York, their westward limit may not exceed St. Louis; and, in further illustration, when Quebec feels the force of the storm, Chicago is at its extreme western limit.  This supposed course will convey the general idea of the track of a northeaster when it envelops the whole variable-climatic district of the Union.  There is a singular eddy known to all climatologists to exist in Iowa, where the annual precipitation of water is great, exceeding that of all the surrounding States.  There has been no positive theory advanced, to our knowledge, explaining this circumstance, but the mystery is solved, to our minds, quite clearly.  This eddy makes the key-point of contact of the humid Gulf winds with the cool winds of the westerly current, and likewise being the northwestern terminal point of the course of the great northeasters, the contact being the cause of the excess in precipitation.  We were fortunate, while visiting last autumn this special wet district of Iowa, to experience one of these triangular storms.  We were at Dubuque while