studied. The respective advantages and disadvantages of the fertile marshy valleys of rivers, so often infested with endemic miasma, ought to be carefully compared with the pure air and bubbling fountains of less fertile mountainous situations. And the emigrant to the Campagnas of the new world should value, against pestilence and impaired health, the buoyant, energetic, prolonged existence of the mountaineer.

It is estimated that the improvements in civilization, and in the arts and arrangements of life, have within the past century, in some of the countries of Europe, increased at least one-third the average duration of human life.

Among the causes of diminished mortality consequent on progressive civilization, and man's observance of the natural laws, are:-the draining of marshes, the embankment of rivers and the location of dwellings in dry and healthful situations-the greater attention to cleanliness in clothing, and in the modes of cleaning towns by aqueducts and subterranean sewers to the ventilation of dwellings and hospitals and public buildings-vaccination and sanitary arrangements, which prevent the importation or communication of contagious diseases the improvements in machinery, the introduction of the steam engine, the cotton plant, the cotton gin, and the cotton spindle, which have promoted the more comfortable clothing of mankindgreater attention to children in their infancy, improved education and laws which limit the hours of their employment in factories, &c.—the better food which an intelligent and improved agriculture produces—the cultivation of justice and benevolence, and the predominance of the moral sentiments and intellect over the mere animal nature.

Among the causes which shorten human life in all climates, are unfavorable seasons and abrupt vicissitudes of temperature, marshy situations,-unsuitable clothingthe effects of labor too long unremitted, especially in child

hood and youth-high prices of food and the necessaries of life, in comparison with the wages of labor-pestilential diseases--the want of cleanliness, and neglect of ventilation and pure air in the dwellings of the poor and of the ich, in school houses, lodging-rooms, and in public assemblies the excessive use of spirituous liquors-drunkenness, and luxury, and indolence—and war, but less in consequence of battles than of forced marches, unhealthful encampments, and the mal-commissariat of armies.

Human life is short under the most fortunate conditions. We all enter life helpless, and totally ignorant. It requires time and experience for very moderate acquisitions of knowledge. In those climates where life is most precarious, the inexperience of youth scarcely gives place to maturer reflection before the infirmities of age are already present-and inevitable dissolution closes the career of the individual before he can have contributed much to the improvement of the species.

On the contrary, in the most healthful climates, which are usually those where the human race is most distinguished for its aggregate good qualities, a much longer interval occurs between the ignorance of youth, and the fatuity of age.

Men who may have at forty years acquired some degree of valuable knowledge, may be expected to enjoy its power, and to enlighten their contemporaries, to carry forward science and legislation during very many years.

In a good climate, a man poor at forty, may die, as did Stephen Girard, possessed of immense wealth; a drunkard at forty may reform, and live many subsequent years of vigorous existence, a good man and wise. The peculiar activity of the nervous temperament, and the reckless application which often shorten the lives of profound students and men of genius, are in healthful climates less destructive,

and such men may live, as did Sir Walter Scott, amid his native hills, to an old age of great intellectual vigor.

Health promotes knowledge, wealth, virtue-it secures to youth the counsels of hoary age, the inherited aggregation of fortune, the transmitted wisdom of actual experience and if it is not virtue, it at least lengthens out to the sinner the chance of reform, of penitence, and of mercy. Moral truths, like intellectual, are not often acquired without experience—nor do virtues, like mushrooms, spring up over night.

A healthful climate, therefore, is a consideration of incalculable importance, and the careful study of the varieties of latitude and climate and the local natural history of the different countries, seems almost to determine the character of its people, and the intellectual and moral results which may fairly be expected from the inhabitants of any locality. Thus it is evident that the human race under neither extreme of temperature, neither in the arctic nor the torrid zones, has produced even an approximation to the master spirits of the Caucasian races; perhaps we might say with more propriety, to the master spirits of the temperate latitudes. A Homer or a Shakspeare in literature, a Newton in astronomy, a Columbus in nautical enterprise, a Cuvier in natural science, or a Napoleon in the field, could only have been nurtured in a fine climate. In the greater or lesser absence of the favorable and equable temperatures necessary to the best development of the human racè, the inhabitants of any country will be found comparatively less intellectual, and less susceptible of those characteristics which ennoble mankind.

Accordingly, as we diverge from the temperate parallels, neither Siberia nor Siam, Arctic America nor sub-tropical Africa, have given names to history: their inhabitants are unavoidably inferior to the natives of more favored regions.

Further to illustrate the influences of climate, let us suppose for a moment that the temperate latitudes had never existed as at present, but that the temperate and torrid zones had traversed earth and ocean in totally different directions, as would have been the case if the axis of the Poles had passed through the present equator-so as to have originally thrown the Caucasian mountains and the British isles into the tropical or Arctic latitudes, and have blessed Congo and Hudson's Bay, Guyana and Kamschatka, with the most temperate climates,-what would have been the present existing condition of their respective inhabitants?-and what would now be the contrasts of condition and character consequent on such a change of climates, continued for a course of ages upon the present inhabitants of those widely differing portions of our planet?

Absolute equality of advantages as regards health and longevity, has obviously not been the intention of the all-wise Creator, any more than the absolute equality of original understanding, for which learned men have sometimes contended.

As hundreds of men have died prematurely of contagious diseases, or of the scarcely avoidable endemics of unhealthful latitudes, who might, under other circumstances of health and longevity, have displayed singular genius; as the accidents of life have destroyed in youth men who, had they lived, would have acquired distinction for their learning or wisdom, or have been beloved for extraordinary virtues; so the characters of whole nations, constituted of the aggregate character of their citizens, may be said to result in some degree from their local advantages of healthfulness, and their predominance among the empires, their superiority, or otherwise in arts, in arms, in science, in morals, in religion, may almost be said to be a birthright derived from the favorable influence of these on their organization. As the character and influence among their cotempo

raries of men of genius, bravery and science, depend upon their actual achievements, so the reputation and influence of nations is a practical result of the aggregate qualities, achievements, and capacities of its citizens. Had England been under the Equator, could she have been mistress of the ocean? If the negroes are a race not inferior to the Moguls and the Malays, why is it that they have not, like these, organized and maintained powerful empires? If the effects of climate are as great as the panorama of the earth seems to illustrate,—the importance of a very patient study of those arts of life, of clothing, of shelter, and of ventilation, by which man protects himself from the vicissitudes of the seasons, and thus artificially produces, even in unfavorable climates, some approach to those equable temperatures which promote health and longevity and all their concomitant blessings, commends itself alike to the physician, to the utilitarian, and to the philosopher.

The Effects of Temperature comprehensively considered.

Our purpose in the present chapter is to illustrate the control of temperatures, in their widest range over the processes of nature and of art.

To this design the following table will be useful, and is perhaps the best introduction that we have in our power at present to offer.

Professor Farraday, availing himself of the intense cold produced by the evaporation of the mixture of solid carbonic acid and ether, under the exhausted receiver of an air pump, and assisted by a pressure equal to 50 atmo→ spheres, has produced the greatest degree of cold yet known to chemists,-166° of Fahrenheit below zero.