same manner, as is felt on the ocean.’
The annual and mean quantity of rain that falls in the United States is much greater than in most countries of Europe, certain mountainous regions and heads of gulfs excepted. This has been ascertained by numerous and accurate observations made on different parts of the Atlantic coast. It is said, on the authority of tabular views, that, on a medium, one third less rain falls in Europe than in the United States; yet Dr. Holyoke mentions, in his memoir on the climate of the United States, twenty cities in Europe, which, at a mean of twenty years, have had one hundred and twenty days of rain; while Cambridge has had but eighty-eight days, Salem ninety-five days of rain, and Philadelphia seventy-six days, at a medium of twenty years. The mean annual quantity of rain at Philadelphia is very little more than the mean annual quantity at Glasgow for a term of thirty years preceding 1790. The above greater quantity of rain, in fewer days, in America, indicates the rain to be much heavier there than in Europe. On the other hand, it is equally well ascertained, that the evaporation of these rains proceeds much quicker in America than in Europe; and that, consequently, the air is habitually drier, and less calm, unless Charleston be taken as an exception. It has been found, that the mean annual quantity of evaporation at Cambridge, near Boston, was fifty-six inches, for a term of seven years; while in seven German and Italian cities, on a mean of twenty years, the annual evaporation was forty-nine inches, or seven of difference; although the Italian cities are in a much more favorable situation for evaporation than the vicinity of Boston, adjacent to the Atlantic ocean. The same fact of greater evaporation was also observed to take place in Upper Louisiana, and along the higher Missouri, as far as the Rocky Mountains, by Captain Lewis.
The habitual dryness of the American climate increases, as we advance west and north-west from the Missouri, where there frequently is not a drop of rain for six months. This is owing to the great distance from any sea, the superior elevation, and the comparative want of timber, combined with the greater intensity and longer duration of the north-west wind, which sweeps with unobstructed force over the naked plains. It appears, then, that more rain falls in fewer days, in America, than in Europe; and that there are fewer cloudy days, more fair days, and quicker evaporation. It is to this last circumstance we must ascribe those immense dews, unknown in European climates, which occur in America, and which are so copious in summer, as to resemble heavy showers of rain. But it must also be observed, that dews are comparatively unknown in the tract watered by the Upper Missouri; and which, in all probability, is owing to the want of timber, wood being limited to the banks of the rivers, which are commonly bordered with trees.
GENERAL REMARKS ON CLIMATE.
It is the opinion of Professor Leslie, that all the varieties of climate are reducible to two causes; distance from the equator, and height above the level of the sea. ‘Latitude and local elevation form, indeed,’ says he, ‘the great basis of the law of climate, and any other modifications have only a partial and very limited influence.’
Climate is generally treated of under four divisions: the cold and humid; cold and dry; warm and humid; hot and dry. But these climates do not always exist according to the full import of the terms by which they are designated. They are subject to modifications, principally of two kinds; the one arising from the alternation of two different climates in the same region, the other from the greater or less prevalence of either of the four elements. Thus when heat, dryness, and humidity are duly combined, they render the climate comparatively temperate. In Egypt, for instance, the combinations of heat and humidity, during the inundation of the Nile, and of heat and dryness during the rest of the year, temper a climate, without which these alternations would be insupportable. In Holland the cold humidity of the autumn is succeeded by frost, which increases the salubrity of the climate, that would not otherwise be so healthy.
The sea exercises an important equalizing influence on the temperature of the globe. In the tropical regions a large extent of ocean spreads coolness on every side, and affords a perpetual succession of refreshing breezes. Islands are always, comparatively, of more temperate climates than continents, and those scattered over the expanse of the Pacific may be said to enjoy almost a perpetual spring. The influence of the winds is also very important; particularly that of the trade-winds. Blowing from east to west across the sands of Africa, the latter produce, on its western coast, a most intense heat, much greater than is experienced on the eastern. In passing the Atlantic they are considerably cooled; and though their temperature is again raised in traversing South America, yet, before reaching the opposite coast, they meet the tremendous snow-clad Andes, which stop their progress and diffuse a wide coolness.
Again, the mountain ranges of the earth not only present and retain on their sides a refreshing coolness, but, by the mighty rivers to which they give rise, diffuse a great amelioration of the temperature through extensive regions. They are particularly of this character, and give rise to the largest rivers in the torrid and burning zones of the earth. In the temperate climate, and those approaching to the poles, mountains are of moderate elevation, are almost always barren, and give rise to few considerable streams.
It appears probable that the climates of European countries were more severe in ancient times than they are at present. Cæsar says that the vine could not be cultivated in Gaul on account of its winter cold. The reindeer, now found only in the zone of Lapland, was then an inhabitant of the Pyrenees. The Tiber was frequently frozen over, and the ground about Rome covered with snow for several weeks together, which very rarely happens in our time. The Rhine and the Danube, in the time of Augustus, was generally frozen over for several months of winter. The barbarians who overran the Roman empire a few centuries afterwards, transported their armies and wagons across the ice of these rivers. Though the fact is well established, the causes of this change of climate do not seem to be satisfactorily explained.
CHAPTER XV.—MINERALS.
IN the ordinary mineral productions, such as brick-earth, stone adapted to building, as well as for any kind of workmanship, and in sand of all qualities, the resources of the United States are inexhaustible. The same may be said of many minerals of less universal occurrence, that may seem to merit a more particular description. To begin with the precious metals. The gold region commences in Virginia, and extends south-west through North Carolina, along the northern part of South Carolina, thence north-westwardly into Alabama, and to its termination in Tennessee. In 1825, Professor Olmsted published a particular account of the gold region of North Carolina, as it was then explored; it has since been found to be vastly more extensive, but the richest mines are still worked in the region which he described, in the counties of Mecklenburg, Rowan, Cabarras, Anson, and Davidson. This account, which is quite minute and interesting, we present slightly abridged in the following pages:
A geographical description of the gold country, would present little that is interesting. The soil is, for the most part, barren, and the inhabitants generally poor and ignorant. The traveller passes a day without seeing a single striking or beautiful object, either of nature or of art, to vary the tiresome monotony of forest and sand-hills, and ridges of gravelly quartz, either strewed coarsely over the ground, or so comminuted as to form gravel. These ridges have an appearance of great natural sterility, which is, moreover, greatly aggravated by the ruinous practice of frequently burning over the forests, so as to consume all the leaves and undergrowth. The principal mines are three—the Anson mine, Reed’s mine, and Parker’s mine.
The Anson Mine is situated in the county of the same name, on the waters of Richardson’s creek, a branch of Rocky river. This locality was discovered by a ‘gold hunter,’ one of an order of people, that begin already to be accounted a distinct race. A rivulet winds from north to south between two gently sloping hills that emerge towards the south. The bed of the stream, entirely covered with gravel, is left almost naked during the dry season; the period which is usually selected by the miners for their operations. On digging from three to six feet into this bed, the workman comes to that peculiar stratum
