Until a comparatively recent date the climate of the continent was held, by all of the more learned in matters of physical geography and climatic law, to have but one general characteristic; but these conclusions have been found to be utterly erroneous, and now it is known to be susceptible of division into three great and entirely distinct areas, each being highly marked, and leaving, on these various surfaces, peculiar evidence of their existence.

Instead of an oceanic climate prevailing over the entire continent, it is found to have but very narrow limits along the Pacific coast of the United States, being broken entirely from the interior by the elevated mountain ranges, conforming to them throughout their entire extent, and having a sweep from near the thirty-sixth parallel to Sitka and the Aleutian Islands, away to the extreme northwest.

The second division embraces the great interior basin lying between the ranges of one hundred and twenty degrees and ninety-two degrees west longitudes, having a general trend from the southwest, at San Diego, to Hudson’s Bay in British America, in the northeast. This vast district is paralleled by that of the interior climate and character of the continent of Asia in its elevation, aridity, and great extent, and may be known as the true continental or Asiatic climate of the United States. It is on the edge of this district, and visibly under its influence, that the State of Minnesota, for the most part, lies. But we pass, for the present, to the brief consideration of the third grand division, embracing the entire country east of a line drawn from near Central Texas to the centre of Wisconsin, including the immediate region surrounding all the great lakes. Here we have an association of elements constituting a highly variable climate, which prevails over all its surface at all seasons, with remarkable uniformity. The wide range in both vegetable and animal life over this area is one of its chief distinguishing characteristics, partaking of the semi-tropical on the one hand, with a low winter temperature on the other, but traversing neither range so far as to prove directly destructive in its effects. All over this eastern area are scattered lakes and rivers, with an ocean boundary line, and uniform forest ranges with a great variety of deciduous trees known to the temperate and sub-tropical latitudes; and it is quite remarkable to note that some of the latter forms extend in their acclimation to near the northern boundary lines of the Union, while the pine, walnut, and chestnut may be found at or near the extreme southern limits.

In all of these three grand divisions of climate, however, exceptional localities exist where there is a marked nonconformity to the prevailing characteristics. The peninsula of Florida is such an exception, owing to its peculiar location, and the great humidity of its atmosphere during a considerable fraction of the year. Here we have a fully developed season of periodical rains, beginning usually in June and ending in the latter part of September. The winter is the dry season, being contrary to the general rule applying to tropical and sub-tropical areas, and forms, with the mild temperature, the principal ground for the reputation which that State has as a resort for special classes of invalids.

The sudden and extreme variations of temperature in this eastern climatic tract, whether from local disturbing causes, as is not unfrequently the case, or otherwise, are usually accompanied by cold draughts of air, chilling and generating all manner of ills, of which rheumatism and consumption are the separate and highest types.

While it is generally understood that the prevailing winds of the whole continent embraced within the limits of the United States are uniformly from the west, still, over this eastern division, counter-winds of a lower character disturb, modify, and elevate the course of this great westerly current, giving rise to the exceeding variability of the surface winds, which, as is well known, may blow within the brief space of twenty-four hours from all directions of the compass, at almost any time and point whatsoever.

Changes of temperature, while essential in some circumstances to health, may be, if of a certain specific character, infinitely damaging, and such are the cold humid winds from the northeast with easterly inclinations. These are the dreadful scourges of all the Atlantic slope above the Carolinas, and there is scarce any portion east of the Mississippi Valley free from their occasional visitation. In the extreme southern limits, along the Gulf, and on the Peninsular State, the poison, so to speak, of this wind, is so far modified by the greater temperature of these localities as measurably to disarm it of danger; yet, even in those latitudes, it is to be (during and after a prolonged storm) avoided by all, and especially weak and enfeebled constitutions.

The cases of consumption found in these warmer climates have been cited as disproving the heretofore accepted theory that this disease was limited in range to the middle and eastern portion of the Union; and it has been further assumed that the liability to its attack was as great there as at any point further north.

These conclusions have little foundation in fact, as is well known by all who have taken pains to investigate the question with that thoroughness which the subject demands. The catalogue of ills belonging to all warm climates is not only long enough, but likewise sufficiently dreadful, without adding to it that scourge, which is the child of the northeast winds, with its home in the changeful temperature along the upper Atlantic coast. It is quite true that cases occur in even tropical districts, but they are the stray offspring of some unusual departure of the cold and humid northerly currents. It must not, however, be taken as a sequence of this proposition that any and all warm countries would prove a sovereign balm and remedy; but, that there are a few localities of this condition in temperature, where patients of the class under consideration may reside with positive advantage, and not unfrequent restoration to health follow, we both believe and know.

But there is so great a liability to contract some of the many fatal febrile, and other diseases of hot countries, together with their usually excessive humid character and greatly enervating effects, especially on those who have been born and reared in cooler and higher latitudes, that it comes to be a serious question for consideration whether the chances of remedy hoped for in a residence at such places is not more to be dreaded than the disease itself.

In what direction, then, can the invalid turn with any immediate or ultimate hope of either relief or a permanent cure? We answer, that any place where a dry, equable climate can be found, all other things being equal, will give the desired relief and probable cure, if resorted to in season, and if certain hygienic regulations be carefully and persistently observed. The next question is, have we a climate answering this important requirement, and, at the same time, outside of the range of epidemics and fatal fevers; easily accessible, and affording, when reached, the necessary comforts and aids incidental to a restoration? To this we have an affirmative reply to give, coupled with some modifications, and point to the Central climatic division of the continent as possessing, in its dry elastic atmosphere and generally equable temperature, the requisite desideratum.

Minnesota lies within this division, and, while upon the outer edge, is still markedly under the influence of the prevailing climate which distinguishes the whole of this middle area. Other sections within its limits there may be, and, indeed, doubtless are, just as favorable, if not more so, than is that of Minnesota, but they are lacking either in facilities for reaching them, or in the needed comforts, and perhaps in the commonest necessities which are absolute in all cases, a wholesome diet being one of the great essentials to recuperation.

Minnesota affords, of course, all of these aids in large abundance, and is likewise quite easy of access, thus answering, in these particulars at least, the ends desired.

It may now be well to examine the chief characteristics belonging to this central climatic division, on the northeastern edge of which lies the State under special consideration. We have already observed that the prevailing and prominent winds of the continent blow uniformly from the Pacific toward the Atlantic coast, having a slight northerly tendency. It is important that this fact be kept in mind. This wind is constantly sweeping across the North Pacific Ocean, by which it is tempered and ladened with a vast amount of moisture, which is borne to the shores of the continent, and, but for the elevated mountain ranges along the whole of that coast, would be quite evenly distributed over the interior, giving to all of the western and central area such an abundance of fertilizing rains as the western half of the continent of Europe now possesses, and to which this would then be in climate almost an exact counterpart. But instead we have only a slender breadth of territory answering to the oceanic climate of Western Europe, embracing that which lies between the Pacific shores and the Sierra and Rocky Mountain ranges. Within this belt is precipitated nearly all of the moisture contained in the atmosphere. The warm, humid westerly winds, driven against the lofty and cool mountain sides, have their moisture suddenly and rapidly condensed, and the rain-fall on their western slope is found by measurement to be prodigious, reaching as high as sixty-five cubic inches for the year, being equal in quantity to that falling in many tropical districts, and greatly exceeding that of any other portion of the United States. These mountains have a determining influence on the climate, both of the coast and of that in the interior. They act on the clouds as they sweep against and over them, like a comb, extracting all possible moisture, leaving a cool, elastic, and arid continental atmosphere for this central area under present review. The effect is at once pronounced and everywhere visible. Less than two degrees of longitude east of these mountain ranges there is but about (taking the whole line from the thirty-fifth parallel to the northern boundary) an average fall of seven and a half cubic inches of rain, a difference of over fifty-five cubic inches within the year, in districts separated by less than one hundred miles in a straight line from each other. The consequence is, that, while in one there is a luxuriant growth in all kinds of vegetation, in the other barren plains (destitute of all except the lowest forms of vegetable life) exist, with a gradual but slow return, as the eastern course of the winds are followed, to that normal condition which prevails in districts where an abundant supply of moisture is furnished. This is not fully found till the western limit of the third climatic division is reached, where again we see on all hands a general distribution of rivers and forests over the whole of this area, with copious rains at all seasons, and humid and cool conditions of the atmosphere, following each other in rapid alternations; producing what we have seen fit to call the Variable climatic district, embracing the whole eastern half of the continent.

The extreme high temperature of the interior division equals that of points lying a dozen degrees south in other longitudes, and the desiccated winds from the west, as they blow over this parched and heated surface, have their aridity rather than their humidity increased, as would be the case in other circumstances; and not till they reach within perhaps five hundred miles of the eastern boundary of this continental division do they increase in humidity, as indicated by the rain-fall, which rises in quantity from the low minimum of seven and a half cubic inches per annum in the “great basin,” and fifteen on the “great plains,” to about twenty in Dakota territory and twenty-five in Minnesota, the eastern limit of this continental climate.

The effect of these dry winds on the humidity of the atmosphere in Minnesota is unquestioned and demonstrable by the records kept of the various governmental posts over the whole country. In contrast, the amount of rain falling annually in this State is shown by these statistics to be much below that of any lying east of the Mississippi, in the variable-climatic district; and, indeed, below that of every other in the entire Union, excepting Nebraska, which averages about the same amount of rain-fall, though without the same amount of dryness and elasticity, which are such notable features in the atmosphere of the former State.

The mean annual amount of rain falling in New England is about forty-three inches, nearly double that of Minnesota, exhibiting the vast difference in the humidity of the two localities, and this, in connection with the cold easterly winds before referred to as prevailing there at intervals, together with the severe changes (and which, it should not be forgotten, add to the quantity of moisture), may be ascribed the primal cause of all pulmonic diseases.

It should not be understood, however, that the quantity of moisture precipitated in any given district determines of itself the prevalence or non-prevalence of phthisic complaints; not at all, for we see in Florida the rain-fall is very great, and as much exceeds that of New England as the latter does that of Minnesota, and consumption has no home on the peninsula of Florida. Why it has not, inheres in this fact, that the climate does not, or rarely, experience any of those violent and chilling changes of temperature that are almost constantly going on, especially in the fall, winter, and spring months, and which do the fatal work of death. But, some one says, the northeast winds reach Florida, and why do not the inhabitants suffer from it? For the reason that they are greatly changed in character, becoming mild and only pleasantly cool in temperature, offering no shock as a rule; and really the northeast trades, which almost daily blow, are the invigorating and healthful winds, sweeping away the miasma of the hot season, cooling the atmosphere, and preserving equability throughout the year. Then there are other matters; the drainage qualities of the soil, which is so great on that peninsula; then, too, is the distribution of the falling rain, whether it is filtered slowly through all the year, keeping things constantly drowned out, or in a state of flabbiness, or whether it is mainly confined to a single season or an inconsiderable fraction of the whole year, as in Florida. These become important inquiries, as all have a bearing on the question of the healthfulness of climates.

We have stated the rain-fall to be less in Minnesota than in any other State in the entire Union, with one exception; and while this is true, it is still great enough for all agricultural uses, coming chiefly in the summer months, at a time when the crops are growing; and, by the middle of September, as a rule, the quantity has fallen off to a very low mean, accompanied by that elastic, invigorating atmosphere for which the State is so justly famed. This season of charming weather continues, with little interruption, only accompanied by a gradual diminishing scale of thermometric registration, up to the advent of winter, and even then the moisture falling in snow is less than is generally supposed or believed.

Since these matters are of vital character in determining the salubrity of the climate of this State, we append the following table, both for the purpose of comparison with other places and definiteness concerning this.

This table gives a sweep of country from ocean to ocean, and exhibits the rain-fall of the three climatic divisions very faithfully. The great quantity precipitated at Astoria, in Oregon, is observed, where the OCEANIC climate prevails, with the mountain barriers limiting its extent inland; while, at Port Laramie, in Wyoming Territory, is an average representation of the whole interior district possessing the dry and elastic CONTINENTAL climate, in which lies the State of Minnesota.