It has an almost artificially perfect arrangement of its larger rivers, both for supply and drainage, is rolling in its surface, having several dividing ridges or water sheds, and varies from 600 to 1,600 feet above the level of the sea, Blue Mounds being 1,729 feet above sea level. Its pine and thickly wooded lands are being rapidly denuded, and to some extent converted to agricultural purposes; its marshes in the north are being reclaimed for cranberry cultivation, and in the more thickly settled parts of the state for hay purposes. The surface of the state is beautifully diversified with stream, waterfall and rapids; richly wooded bluffs several hundred feet in height, assuming the most romantic and pleasing forms, and composed of sandstone, magnesian limestone, granite, trap, etc. The health and summer resorts of Wisconsin are illustrative of its beauty, and its numerous mineral springs have long since formed an important feature of its character for salubrity.

GEOLOGY.

The geology of Wisconsin does not require from us but a very general notice, as it is only from its relation to disease that we have to consider it. This relation is in a measure apparent in the fact that everywhere the topographical features are governed by the strata below them. The relationship will be seen still further in the chemical or sanitary influence of the geological structures. Through the greater part of the south half of the state limestone is found, the cliff prevailing in the mineral region, and the blue in the other parts; while in the north part of the state the primitive rocks, granite, slate, and sandstone prevail. South of the Wisconsin river sandstone in layers of limestone, forming the most picturesque bluffs, abounds. While west of Lake Michigan extends up to these rocks the limestone formation, being rich in timber or prairie land. Sandstone is found underneath the blue limestone. The general dip of the stratified rocks of the state is toward the south, about 8 feet to the mile.

In

Medical geology treats of geology so far only as it affects health. Thus, some diluvial soils and sands are known to be productive of malarial fevers; others, of a clayey character, retaining water, are productive of cold damp, and give rise to pulmonary and inflammatory diseases; while others still, being very porous, are promotive of a dry and equable atmosphere. the Potsdam rocks arise our purest waters and best supply, while our magnesian limestone rocks (a good quality of this kind of rock being composed of nearly equal parts of carbonate of lime and carbonate of magnesia) affect the water to the extent of producing.simple diarrhoea in those unaccustomed to drinking it, as is observed in southern visitors, and was especially noticeable in the rebel prisoners at Camp Randall, though singularly enough do not seem to produce stone and gravel, as is alleged of the same kind of water in the north of England. Why this is so if so-is a question of some interest. Goitre and cretinism are both attributed to the use of the same magnesian limestone water. Goitre is by no means an uncommon affection here, but not common enough, perhaps, to warrant us in thinking its special cause is in the water. Boiling the water is a preventive of all injurious effects. There is still another objection — particularly applicable to cities-to this kind of water, the carbonates of lime and magnesia which it contains, not simply making it hard, but giving it the power to promote the decomposition of organic matters, and thus where the soil is sandy or porous, endangering the purity of our wellwater. Geology in general affects all our soils and their products; all our drainage; even our architecture, the material with which we build. Our building stone for half of the state is a magnesian limestone, a rather soft or poor quality of which will absorb one-third of its bulk of water, or two and a half gallons to the cubic foot, while most kinds of sandstone are nearly as porous as loose sand, and in some of them the penetrability for air and water is the same. (A single brick of poor quality will absorb a pint of water). Such materials used in the construction

of our dwellings, without precautionary measures, give rise to rheumatism, other grave diseases, and loss of strength. Besides, this character of stone absorbs readily all kinds of liquid and gaseous impurities, and though hardening in dry air, decays soon when exposed to underground moisture. The material of which our roads are made, as well as the kind of fuel we use in our homes, have the same unquestionable relationship to geology and disease.

DRAINAGE.

The natural drainage of the state, bearing in mind that the mean elevation of its hydrographical axis is about 1,000 feet above the sea level, is as excellent as it is obvious. (A line running from Lake Michigan across the state to the Mississippi, shows an elevation of about 500 feet). North its drainage is by a few rapid but insignificant streams into Lake Superior, while east it increases greatly and enters Lake Michigan by way of Green bay. The principal part of the supply and drainage, however, is from the extreme north to the southwest through the center of the state, by five large rivers, which empty themselves into the Mississippi at almost equal distances from each other.

CLIMATOLOGY.

The climatology of Wisconsin will be exhibited in the observations taken at different times, for longer or shorter periods, and at different points of the state. But it must be borne in mind that climate depends quite as much and very frequently more upon the physical surroundings, upon the presence of large bodies of water, like our lakes, upon large forests, like our pineries, like our heavy hard-woods, and of land elevations and depressions, upon isothermal lines, etc., as it does upon latitude. Our historic period is of a character too brief for us to assume to speak of our climate, or of all the changing causes which influence it—in a positive manner, our horticultural writers, to make the difficulty still greater, affirming that it has several climates within itself; still, sufficient data have been gathered from sufficiently reliable sources to enable us to form a tolerably accurate idea of the subject.

The great modifiers of our climate are our lakes. These, bounding as they do, the one, Lake Superior (600 feet above the level of the sea, 420 miles long and 160 broad), on the north side of the state, and the other, Lake Michigan (578 feet above the sea level, 320 miles long and 84 broad), on the east side of the state, serve to govern the range of the thermometer and the mean temperature of the seasons, as much as they are governed in New England by the ocean. Our climate is consequently very much like that of the New England sea-board. They both exhibit the same extremes and great extremes, have the same broadly marked continental features at some seasons, and decided tropical features at others. It is of special interest in this connection to know that the climate between the eastern coast and the lakes increases in rigor as one advances west until the lakes are reached, and again becomes still more rigorous as one advances into the interior west of the lakes, thus affording proof, if proof were wanting, of the modifying and agreeable influences of large bodies of water

During the winter the mean temperature of the east on the New England coast is 8.38 higher than the west (beyond the lakes); during the spring 3.53 lower; during the summer 6.99 lower; and during the autumn 1.54 higher. In the mean temperature for the year there is but a fractional difference. That the winters are less rigorous and the summers more temperate on the Great Lakes is demonstrated to be owing not to elevation, but, as on the ocean, to the equalizing agency of an expanse of water.

On the lakes the annual ratio of fair days is 117, and on the New England coast 215; the

cloudy days are as 127 to 73; the rainy as 63 to 46, and the snowy as 45 to 29 In the former the prevailing weather is cloudy, and in the latter it is fair. The immense forests on the upper lake shores of course exercise a considerable influence in the modification of our temperature, as well as in the adding to our rain-fall and cloudy days. A climate of this character, with its attendant rains, gives us that with which we are so abundantly supplied, great variety of food, both for man and beast, the choicest kinds of fruits and vegetables in the greatest profusion, and of the best quality, streams alive with fish, woods and prairies with game, the noblest trees, the most exquisite flowers, and the best breeds of domestic animals the world can boast of.

The semi-tropical character of our summer, and its resemblance to that of New England, is shown by the mean temperature -70°- for three months at Salem, Massachusetts, at Albany, New York, at southern Wisconsin, Fort Snelling and Fort Benton on the Upper Missouri, being the same; while at Baltimore, Cincinnati and St. Louis, it is 75°, and around the gulf of Mexico it is 80°. Another feature of our climate is worthy the notice of invalids and of those who make the thermometer their guide for comfort. It is a well-ascertained fact that during the colder seasons the lake country is not only relatively, but positively, warmer than places far south of it. The thermometer, during the severe cold of January, 1856, did not fall so low at the coldest, by 10° to 15° at Lake Superior as at Chicago at the same time. This remark holds true of the changes of all periods of duration, even if continued over a month. The mean temperature at Fort Howard, Green Bay, Wisconsin, 600 feet above the level of the Atlantic, latitude 44° 40', longitude 87°, observations for nine years, is 44.93; and at Fort Crawford, Prairie du Chien, Wisconsin, 580 feet above the level of the Atlantic, latitude 43° 3', longitude 90° 53', observations for four years, is 45.65, giving a just idea of our mean temperature for the state. Under the head of distribution of heat in winter, it is found that the maximum winter range at Fort Winnebago, Wisconsin, for sixteen years, is 9.4.

HYETAL or RAIN CHARACTER.

Wisconsin is situated within what is termed the area of constant precipitation, neither affected by a rainy season, nor by a partial dry season. The annual quantity of rain on an average for three years at Fort Crawford, was 29.54 inches, and at Fort Howard the mean annual on an average of four years, was 38.83 inches. The annual quantity of rain, on an average of three years was 31.88 inches at Fort Winnebago, situate (opposite the portage between the Fox and Wisconsin rivers) 80 miles west of Lake Michigan and 112 miles southwest of Green Bay. The rain-fall is less in the lake district than in the valley of the Mississippi in the same latitudes. One of the peculiarities of our winters is the almost periodical rain-fall of a few days in the middle of the winter (usually in the middle of January), which extends to the Atlantic coast, while north and northwest of us the dry cold continues without a break, winter being uniform and severe, characterized by aridity and steady low temperature. Another peculiarity of our climate is, the number of snowy and rainy days is increased disproportionately to the actual quantity — the large bodies of water on the boundaries of the state, contrary to the popular opinion, reducing the annual quantity of rain in their immediate vicinity instead of adding to it, the heavier precipitation being carried further away. One of the most pleasing features of our climate is its frequent succession of showers in summer, tempering as it does our semi-tropical heat, increasing the fertility of the soil, and carpeting our prairies with a green as grateful to the eye as that of England.

The hygrometric condition of Wisconsin may be judged of with proximate accuracy by that given of Poultney, Iowa:

The average depth of snow for three years, at Beloit, Wisconsin, was twenty-five inches, while at Oxford county, Maine, the average for twelve years was ninety inches. The isohyetal lines of the mean precipitation of rain and melted snow, for the year 1872, show that of Wisconsin to be thirty-two.

ISOTHERMS.

The mean temperature of spring is represented by the isotherm of 45° F. which enters Wisconsin from the west about forty miles south of Hudson, passing in a nearly southeast direction, and crosses the south line of the state near the west line of Walworth county. It then passes nearly around the head of Lake Michigan, then northeast until it reaches the latitude of Milwaukee, whence it passes in a somewhat irregular course east through Ontario, New York, and Massachusetts, entering the ocean in the vicinity of Boston. The summer mean isotherm of 70° F. enters Wisconsin from the west but little farther north than the spring isotherm, and passes through the state nearly parallel with the course of that line, crossing the southern boundary near the east line of Walworth county; passing through Chicago it goes in a direction a little south of east, and enters the Atlantic at New Haven. The mean isotherm of 47° F. for autumn, enters the state about twenty miles north of Prairie du Chien, passing in a direction a little north of east through Portage, and enters Lake Michigan near Manitowoc. The isotherm of 20° F. representing the mean temperature of winter, enters the state near Prairie du Chien, passes east and north and enters Lake Michigan at Sturgeon bay. The annual mean temperature is represented by the isotherm of 45° F. which enters the state near Prairie du Chien, passes across the state in a direction a little south of east, and enters Lake Michigan a little south of Milwaukee.

What influence these isotherms have upon our belts of disease there are no data to show. But from their influence upon vegetable life, one can not but infer a similar good influence on the animal economy. This is a question for the future.

BAROMETRICAL.

Yearly mean of barometer at 32° F. as observed at the University of Wisconsin, altitude 1,088 feet above the sea:

Atmospheric pressure, as indicated by the barometer, is an important element in the causation. of disease, far more so than is generally thought. The barometer indicates not only the coming of the storm, but that state of the atmosphere which gives rise to health at one time, and to disease at another. When the barometer is high, both the body and mind have a feeling of elasticity, of vigor and activity, and when the barometer ranges low, the feelings of both are just the reverse; and both of these states, commonly attributed to temperature, are mostly the result of change in the barometric pressure. Many inflammations, as of the lungs, etc., commonly

attributed to change in the temperature, have their origin in barometrical vicissitudes.

WINDS.

It is of little purpose

Generally speaking, the atmospheric movement is from the west. what the surface wind may be, as this does not affect the fact of the constancy of the westerly winds in the middle latitudes. The showers and cumulus clouds of the summer always have this movement. The belt of westerly winds is the belt of constant and equally distributed rains, the feature of our winds upon which so much of our health and comfort depends.

CLIMATOLOGICAL CHANGES FROM SETTLING THE STATE.

There are many theories afloat concerning the effects of reclaiming the soil and the destruction of its forests. To us, a new people and a new state, the question is one of great moment, the more so that it is still in our power not only to watch the effects of such changes, but still more so to control them in a measure for our good. As to the effects upon animal and vegetable life, it would appear that so far as relates to the clearing away of forests, the whole change of conditions is limited to the surface, and dependent for the most part on the retention and slow evaporation in the forest, in contrast with the rapid drainage and evaporation in the open space. The springs, diminishing in number and volume in our more settled parts of the state, do not indicate a lessening rain-fall. It is a well ascertained fact that in other places so denuded, which have been allowed to cover themselves again with forests, the springs reappear, and the streams are as full as before such denudation. With us, happily, while the destruction of forests is going on in various parts of the state, their second growth is also going on, both in the pineries, where new varieties of hard-wood take the place of the pine, and in the more cultivated parts of the state, cultivation forbidding, as it does, the practice so much in vogue some years ago, of running fires through the undergrowth. Thus, though the renewal of forests may not be keeping pace with their destruction, it would seem clear that as time advances, the springs and streams in the more cultivated sections of the state will fill and flow again, increasing in proportion as the second growth increases and expands.

The change, however, from denudation, though strictly limited to the surface, affects the surface in other ways than simply in the retention and evaporation of rain. When the winter winds are blowing, the want of the sheltering protection of belts of trees is bitterly felt, both by man and beast. And so, too, in the almost tropical heats of the summer; both languish and suffer from the want of shade. Nor is the effect of denudation less sensibly felt by vegetable life. The growing of our more delicate fruits, like the peach, the plum, the pear, the better varieties of the cherry and gooseberry, with the beautiful half-hardy flowering shrubs, all of which flourished sc well in a number of our older counties some twenty years ago, are as a rule no longer to be found in those localities, having died out, as is believed, from exposure to the cold winds, to the south west winds in particular, and for want of the protecting influence of the woods. In fruits, how ever, we have this compensation, that, while the more tender varieties have been disappearing, the hardier and equally good varieties, especially of apples, have been increasing, while the grape (than which nothing speaks better for climatology), of which we grow some 150 varieties, the strawberry, the raspberry, blackberry and currant, etc., hold their ground. Nor are the cattle suffering as much as formerly, or as much as is perhaps popularly believed, from this want of forests or tree shelter. With the better breeds which our farmers have been able of late years to purchase, with better blood and better food, and better care, our stock instead of dwindling in condition, or in number, from the effect of cold, has progressed in quality and quantity, and competes with the best in the Chicago and the New York markets.