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 of gravel and tenacious blue clay, which is at once recognised as the repository of the gold. The stream itself usually gives the first indications of the richness of the bed through which it passes, by disclosing large pieces of the precious metal shining among its pebbles and sands. Pieces unusually large were found by those who first examined Anson’s mine, and the highest hopes were inspired. On inquiry, it was ascertained that part of the land was not held by a good title, and parcels of it were immediately entered; it has since been the subject of a constant litigation, which has retarded the working of the mine.
Reed’s Mine, in Cabarras, is the one which was first wrought; and at this place, indeed, were obtained the first specimens of gold that were found in the formation. A large piece was found in the bed of a small creek, which attracted attention by its lustre and specific gravity; but it was long retained in the hands of the proprietor, through ignorance whether or not it was gold. This mine occupies the bed of a branch of Rocky river, and exhibits a level between two hillocks, which rise on either side of the creek, affording a space between from fifty to an hundred yards in breadth. This space has been thoroughly dug over, and exhibits at present numerous small pits, for a distance of about one fourth of a mile on both sides of the stream. The surface of the ground, and the bed of the creek, are occupied by quartz, and by sharp angular rocks of the greenstone family. The first glance is sufficient to convince the spectator, that the business of searching for gold is conducted under numerous disadvantages, without the least regard to system, and with very little aid from mechanical contrivances.
Large pieces of gold are found in this region, although their occurrence is somewhat rare. Masses weighing four, five, and sometimes six hundred pennyweights are occasionally met with, and one mass was found that weighed in its crude state twenty-eight pounds avoirdupois. This was dug up by a negro at Reed’s mine, within a few inches of the surface of the ground. Marvellous stories are told respecting this rich mass; as that it had been seen by gold hunters at night reflecting so brilliant a light, when they drew near to it with torches, as to make them believe it was some supernatural appearance, and to deter them from further examination. No unusual circumstances, however, were really connected with its discovery, except its being found unusually near the surface. It was melted down and cast into bars soon after its discovery. The spot where it was found has been since subject to the severest scrutiny, but without any similar harvest.
Another mass, weighing six hundred pennyweights was found on the surface of a ploughed field in the vicinity of the Yadkin, twenty miles or more north of Reed’s mine. Specimens of great beauty are occasionally found, but, for want of mineralogists to reserve them for cabinets, they have always been melted into bars. Mr. Reed found a mass of quartz, having a projecting point of gold, of the size of a large pin’s head. On breaking it open, a brilliant display of green and yellow colors was presented.