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other sour plants. But generally the soils of all this region are highly improvable, resting for the most part on a basis of red or yellow clay. The real soils of Albemarle and Goochland are proverbial for their fertility. Clover grow's well wherever the land has not been exhausted, and plaster has a tine effect. Should lime ever become accessible at a moderate cost, this may be made one of the finest, as it is one of the most salubrious, districts in the State.
According to all analogy we should expect to find limestone accompanying the coal measures of Chesterfield, Henrico, and Goochland. But not a trace exists, with the exception of a thin crystalline deposit of pure carbonate of lime, resting immediately on the granite which forms the bed of the coal basin. This extensive coal-field is thought by geologists to have been deposited long subsequent to those of other coal districts, and therefore not properly belonging to the carboniferous era. It affords the only instance, it is believed, in which the coal is superimposed immediately above the granite. This is not uniformly the case, however, on account of the frequent and violent dislocations that are found to occur in every part of the basin yet explored, and which in the sinking of a shaft render the striking of a seam as much a matter of chance as of science. Thus far, coal has been raised only on the castern and the western boundary of the basin, which is from eight to ten miles in width; and, from the great dip of the strata, it is hardly possible it will ever be raised from the middle, not even by means of drifts. Already there are numerous pits from seven hundred to eight hundred feet deep within a mile of the outcropping.
The fine coal which accumulates at the mouths of the shafts has been used for agricultural purposes, and not without benefit. But the effect is perhaps only mechanical, by improving the texture of heavy soils, or contributing to the warmth of those which are cold by a freer admission of the sun's rays.
The only extensive deposit of gypsum in the State, as far as we have any knowledge, is situated in the extreme southwestern portion, in the counties of Smyth and Washington. It is found in the val. leys of the North Holston River and of Walker's Creek, between Walk. er's Mountain and Clinch Mountain, and stretches along these valleys for forty miles in a nearly east and west direction. The plaster occurs as boulders, some of which are of immense size, imbedded in clay. The deposit is believed to have great depth, and practically it may be regarded as inexhaustible. The beds have not been worked to any great extent, though enough has been taken out to supply the wants of the suurrounding country. It has found its way also along the Virginia and Tennessee railroad as far as Liberty, in Bedford County, and from this and other points on the road over the mountain into Botetourt, and some is sent in boats down the Holston River. There can be no donbt that with convenient access to a market by railroad or water, with transportation at reasonable rates, the whole State, above tide water at least, could be supplied with plaster at prices considerably less than for Nova Scotia plaster. The beds are several miles from the railroad, so that at present the plaster has to undergo the expensive process of hauling in wagons; but it is understood that efforts are being made to get a branch road, or tram-way, to the banks. An analysis by Professor Gilham makes this plaster equal in all respects to the Nova Scotia.
CONCENTRATED FERTILIZERS IN THE SOUTH
THE PECULIAR WANTS OF SOUTHERN AGRICULTURE.
Cotton planting, the product of which is largely exported and which demands constant tillage, and the occasional heary rains falling on light plowed ground easily washed, tends powerfully to denndle and impoverish the soil. As no cotton, grain, or tobacco oan be raised without cultiva. tion, and frequent heavy rains are as distinctive in their character as any other feature of our climate, fertility can be maintained in long-cultivated fields only by restoring to the soil in some way the elements of crops removod partly by washing rains and partly by fertilizing atoms consumed in the growth of cultivated plants. Hence, planting industry in a semi-tropical climate requires for its highest usefulness and success far more manure derived from sources outside of the plantation than ordinary farming, or mingled grass and grain culture with stock husbandry. Under the latter system the farmer has superior advantages for the home production of fertilizers froin live stock, that give a profit independent of their manure. Fields seeded to permanent grass or in clover are generally exempt from injurious surface washing, while all the fertilizing substances contained in a rich turf, and in the valuable roots, stems, and leaves of clover, are drawn, in part at least, from the atmosphere and the deop subsoil. To exclude from cotton plantations all clover, grass, culture and stock growing is not wise, unless one may command at a low price concentrated commercial manures that will at once maintain the fruitfulness of every field and return a satisfactory profit. Commendable efforts have been made, and are still in progress and increasing, to supply manures of this character. They are essentially such elements of fertility as disintegrated rocks yield to the best clay, sand, and soils. Such plant-food as rain water and the atmosphere supply over every poor field as generously as oter those most productive, are to a large extent left out. Concentration means the exclusion of all atoms in inanure that experience proves to be of less value than those retained. A fertilizer that has no greater value, pound for pound, than common yard and stable manure, will not bear long and expensive transportation, if the planter obtained it in the first instance for nothing. Concentration, therefore, is a matter of the greatest practioal importance where land by the hundred million acres, remote from commercial centers, is to be fertilized by commercial manures. As far as the planter, farmer, or stock raiser sends a bale of cotton, barrel oť flour, or fat steer to market, which takes from the soil a part of its indispensable phosphates, sulphates, potash, and other bases, the principle of restitution should be applied and compensation made, if need be, by the return of the fertilizing substances named. A nation of farmers and planters who cultivate poor land without manure must, from the necessities of the case, support half of its entire population in poverty, ignorance, and a low standard of material and moral comfort. Unproductive labor enriches no one, while it denies that “hope of reward” which is the very life and inspiration of happy industry. A nation heavily in debt can ill afford to cultivate land too poor to return more than a bare subsistence to the millions that live upou it; and it is still worse economy to impoverish, from the lack of manu, the fraitful lands that remain to us of our noble inheritance. Not only our cotton growing interest in the South, but our wheat and corn grow. ing interests everywhere, demand the raw material for making crops at the cheapest rate it can be furnished by the best talent, science, and art in the country. Let us examine some of our resources in the planting States to supply the essential food of plants.
SALTPETER CAVES IN THE SOUTH.
It is a historical fact of no inconsiderable agricultural importance that, during the last war with Great Britain, when our coasts were blockaded, saltreter was made for gunpowder from the nitrate of lime taken from the Mammoth Cave in Kentucky. Similar caves, but less in extent, in North Alabama, Middle and East Tennessee, and Virginia, furnished a large but unknown quantity of this nitrate during the recent civil war. One of these niter-producing caves exists on the farm of Dr. Lee, about twenty-five miles below Knoxville, and another on the farm where he resides, near the French Broad River, in Knox County. The saccessful use of nitric acid, in combination with potash, soda, lime, and magnesia, as a fertilizer, leaves no room for doubt that a pound of nitrogen in this form is not less valuable as plant-food than an equal weight in the form of ammonia. Therefore, whoever can produce the nitrate of lime, in a cave or elsewhere, may produce the most valuable constituent in Peruvian guano, an imported manure worth eighty dollars a ton in Baltimore, and ninety-five dollars a ton in several southern cities. Deprive this expensive manure of its nitrogen, and its market value will fall at once to less than half of its present price, although the average quantity of nitrogen contained in it does not exceed twelve per cent.
As a source of assimilable nitrogen, nitrification is a matter that well deserves the study of every planter and farmer. It is not more certain that common mold and toad-stools grow on a dung heap than that saltpeter will grow at the expense of atmospheric nitrogen and oxygen, under favoring conditions. Nitric acid probably exists more abundantly in Chili and Peru, in combination with soda as cubic-niter, than in any other countries; and it is found under conditions that forbid the idea that the acid has a vegetable or animal origin. Nitrification appears to resemble combustion, with this difference: carbon, hydrogen, sulphur, and phosphorus, barn and form acids without the aid and presence of any base to unite with the acid generated ; while the combustion of nitrogen with oxygen requires the aid of a present alkali or alkaline base to combine with and take up nitric acid as fast as it is formed. Decaying animal or vegetable matter liberating nascent nitrogen in the presence of lime in our caves, of soda in Chili, and potash in many places, may be, and probably is, necessary to start the formation of nitric acid; but nitrification once going on, with an abundant supply of oxygen and nitrogen present, and lime greedy to cousume the acid as soon as formed, much more niter appears in the result than the organic inatter will account for by the nitrogen supplied. Precisely what varying conditions extinguish the chemical action called nitrification are not known. The subject loses some of its practical importance on limestone land, from the fact that with clover and a little plaster we can (lraw assimilable nitrogen directly from the atmosphere cheaper in all our fields than we can produce it in caves or elsewhere, to be used as a manure. The consumers of Peruvian guano pay more for assimilable nitrogen than it is fairly worth. Bringing nitrogen from Peru to this country and Europe for manure is about as wise as the transportation of brick from Holland to build houses on the clay banks of Albany, New York, and from England for a similar purpose in the colonies of Virginia and Maryland. On non-calcareous soils the nitrate of lime may be used at a large profit. It is worthy of remark that, in the absence of an alkaline base, nitrogen liberated from decay. ing substances unites with hydrogen to form one (ammonia) in preference to combining with oxygen to form an acid. The chemistry of the dung-heap and of all agricultural salts is alike inviting and instructive, and it is strange, or at least unfortunate, that planters and farmers who invest thousands in acids and alkalies for manure every year, are so unwilling to study their mutual affinities, origin, and agricultural force. The action of lime in saltpeter caves suggests its use in composts, on the farm, and as a fertilizer in the soil everywhere. If lime in rocks and soils does not augment fruitfulness, why are the limestone districts in Virginia, Kentucky, Tennessee, and Alabama (not to name those in New York, Pennsylvania, and Ohio) so remarkable for their fertility ? Lime as the base of an acid will convey into the circulation of agricultural plants carbon, nitrogen, chlorine, sulphur, and phosphorus; but all these elements of crops must be in the soil, within its reach and in an available form.
Having briefly noticed nitrogen in connection with lime as a fertilizer, phosphorus will next be considered as it is found in
THE BONE PHOSPHATES OF SOUTH CAROLINA.
There is reason to believe that the richest deposit of bone phosphates on the continent, and, as far as known, in the world, exists in South Carolina, not far from Charleston. Dr. Pratt, of that city, whose analytical researches developed the full value and significance of this wonderful mine of phosphoric acid, says:
66 This bed has long been known in the history of the geology of South Carolina as the · Fish-bed of the Charleston basin,' on account of the abundant remains of marine animals found in it; Professor Holmes, of Charleston College, having not less than 60,000 sharks' teeth alone, some of them of enormous size, weighing from two to two and a half pounds each. The bed outcrops on the banks of the Ashley, Cooper, Stono, Edisto, Ashepoo, and Combahee Rivers; but is developed most heavily and richly on the former, and has been found as far inland as forty or fifty miles. Near the Ashley River it paves the public highways for miles; it seriously impedes and obstructs the cultivation of the land, affording scarcely soil enough to hill up the cotton-rows; and the phosphates have for years past been thrown into piles on the lawns and into causeways over ravines, to get them out of the reach of the plows. It underlies many square miles of surface continuously at a depth ranging from six inches to twelve or more feet; and it exists in such quantities that from five hundred to a thousand tons underlie each acre. In fact, it seems there are no rocks in this section which are not phosphates."
From these fossil bones and teeth the Wando Mining and Manufacturing Company of Charleston have made, with other ingredients, a fertilizer, which is sold at sixty dollars a ton, which proves, in many instances, equal in value as a manure to Peruvian guano that costs
eighty dollars a ton. Others are successfully manufacturing soluble phosphates from these organic remains. Bones of fresh-water animals, and still more, perbaps, of land animals, are found with those grown in salt water. Indeed, there is no reason why this great “ Fish-bed of the Charleston basin," as Professor Agassiz named it more than twenty years ago, should not supply soluble phosphoric acid in its most available form ; for the bones of the mastodon still retain some two and a balf per cent. of their organic matter, and yield on analysis eighty. five per cent. of bone phosphates. Restore the fat, gelatine, water, and carbonate of lime that existed in these organic bodies when the animals died, and the phosphates will be redueed from eighty-five per cent. to about fifty-five per cent. Time has eliminated elements of little value as plant-food (except nitrogen) in fresh bones, and thereby concentrated phosphorus into a smaller volume for distant transportation and use as a manure.
After citing the results of thirty analyses of as many samples of these extensive deposits, some nodular, hard conglomerates, once thought to be silicious fossils, and some the soft débris of bones, with a part of the organic matter still remaining, Dr. Pratt sums up their advantages in these words:
"1st. The percentage of the phosphate of lime is high. 2d. The carbonate of lime and phosphate of iron and alumina are unusually low. 3d. Its composition is more 'uniform and regular than that of any other known stratum of a similar nature. 4th. Its mechanical or physical qualities are such that it is easily ground. 5th. It contains no mineral phosphate, but is without doubt purely animal in its origin.
“ With these immense advantages in its favor, we may fearlessly throw it on the market, and feel that in one other product, besides cotton, rice,.and lumber, we are independent of the world.”
A citation indicative of the extent of this available mass of bone earth, in addition to those above given, may satisfy cautious readers. The same author states in another place, that the area of this bed con. taining phosphates of good quality, and in workable quantity, so far as known and examined by the writer in person, is not less than forty or fifty square miles; though from samples I have examined from beyond these limits, I am led to believe that the rock will be found of good or indifferent quality, and in greater or less quantity, over an area of several hundred square miles.”
So large a supply of phosphorus of animal origin in or near tbe center of the best cotton-growing country in the world, whether long staple or short, is a fact hardly less important in its financial, commercial, and manufacturing aspects than in its agricultural significance. Nothing will contribute so much to keep the nation's large and growing foreign trade in a safe and profitable condition, yielding an immense revenue by import duties, as the cheap production of cotton under a system of tillage and plantation economy that will impart a high degree of fruitfulness, in perpetuity, to all our planting lands; as naked, gullied, abandoned old fields, they are valueless; but with good concentrated manure, easily drilled in with cotton-seed, they often return an annual profit of from $10 to $100 per acre; crops ranging from five hundred to a thousand pounds of good merchantable cotton are raised by the aid of commercial fertilizers. At twenty cents a pound, the profits are most satisfactory to the planter and manufacturer of superphosphates.
Dr. Pratt's “Chemical History" of South Carolina phosphates has the following tables, on pages 20 and 21: