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 decaying 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:

"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 phos phates 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, perhaps, 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 half per cent. of their organic matter, and yield on analysis eightyfive 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 reduced 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 containing 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 the 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:

Tabulated results of analyses made in the months of August and September, 1867, together with a few analyses of other chemists, for comparison.

Alkalies, magnesia, sulphates, chlorides, fluorides, water, &c., not effimated.

63.30

1.50

1.32

5.02 3.01

68.03 66.36 GL. 93 64.07
0.84

€9.00 39.07 49.35

1.04

65 1.84

10.33 8.20

8.03

11. 21

11.00

5.68

23.40

6.50

7.50

HOW TO UTILIZE BONE PHOSPHATES.

When separated from all impurities, by washing or otherwise, as far as practicable, phosphates should be broken fine enough to grind be tween heavy millstones, which should be dressed to do as perfect work as possible. The finer the flour is ground the easier its particles dissolve in any acidulated water. Thorough drying before grinding favors extreme comminution when reducing the rock to powder. How far heat may be profitably carried to aid in the complete disintegration of bones or bone phosphates, experiments will determine. When properly ground the fertilizers may be handed over to farmers and planters for solution in that admirable crucible known as a hot, fermenting dungheap.

It is true that the sulphate of lime obtained by treating ground bones or guano with oil of vitriol is valuable as a manure; but gypsum will supply the same fertilizer at less than half the cost of the vitriol. Economy demands that cultivators of the soil purchase sulphuric acid in the shape of land plaster, not in the form of a separate acid, as applied to bone phosphates. But as some families buy wheat flour after it is baked into bread, so many farmers may prefer to purchase plantfood ready cooked for use.

A late number of the Journal of the Royal Agricultural Society of England contains an elaborate paper "On the solubility of phosphatic materials with reference to the practical efficacy of the various forms in which bones are used in agriculture," by Dr. Voelcker, chemist to the society. His researches have been thorough, and are reliable. He says: High-pressure steam renders bones so brittle that they can be easily ground into fine powder, which is readily assimilable by plants."

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This is all that any plants need in a manure. He continues: "Bone-meal prepared by high-pressure steam contains not much less nitrogen than ordinary bone dust, and as a manure is far more efficacious and valuable than the latter. Placed in a heap with ashes or sand, and occasionally moistened with liquid manure or water, bone enters into putrefaction, and becomes a more soluble and energetic manure than ordinary bone dust. An excellent way of making bone dust soluble, it may also be mentioned, is the Norfolk plan of putting it into alternate layers between fresh farm-yard manure, and letting both ferment together in a conical heap, covered up with earth, to prevent the loss of any fertilizing matter, and secure it from penetration by heavy rains."

Norfolk farmers have long been distinguished as the best in England, which is equivalent to saying they are the best in Europe, and in the world. While many thousands in Great Britain, on the Continent, and in America, use expensive sulphuric acid to dissolve bone phosphates, Norfolk farmers accomplish the same result by warm carbonic acid, water, and nitrogenous substances in fermenting manure. At the market price of sulphuric acid in the South, planters now pay as much for one pound in superphosphates as ten pounds of the South Carolina bone flour ought to cost at the mills where it is ground. The chemistry of plant and animal food and nutrition will never do much for agriculture before the true economy and principles of this science are carried home to the fireside and understanding of the men who own and cultivate the soil. Farmers, who are large consumers of acids, alkalies, and alkaline earths, ought to study all their chemical relations in compost heaps, soils, plants, and animals. Every farmer and planter should be able to inquire understandingly in what way nature dissolves the apparently insoluble carbonate of lime, phosphate of lime, and silicate of potash in soils, to promote the growth of plants. There is no reason to believe that sulphuric acid is in any way applied to that object. Carbonic acid, and others of vegetable origin, are sufficient for the purpose. Water charged with carbonic acid (the cheapest acid known) dissolves the carbonate of lime freely, acts sensibly on the silicates of lime, potash, and soda, and on bone phosphate reduced to a fine powder. Strong vinegar can be made from sorghum sirup, and used as a solvent on the farm cheaper than sulphuric acid can be bought and used for agricultural purposes. In a word, the same organic acids formed in decaying dung-heaps and in good soils, that render the mineral elements of crops available, as obtained from particles of feldspar, mica, hornblende, and other compound minerals as they exist in clay and sand, are at the service of the farmer to bring South Carolina bone phosphates into solution. Give us the osseous remains of extinct vertebrated animals as pure, as finely ground, and as cheap as possible, and southern planters and farmers will do all else that is needful to reorganize them as parts of living beings.

THE SOURCES OF PHOSPHORUS AND SULPHUR IN SOILS.

While commercial enterprise explores every sea to find islands and rocks covered with the excrements of birds to be imported and used as manure; and while geologists and chemists search earnestly in the beds of post-pliocene rivers, lakes, bays, and estuaries for the bones of land and sea monsters developed in an age when oysters in Georgia built up banks of their shells two hundred feet in thickness, with specimens still found one hundred miles from the Atlantic, that measure from eighteen to twenty inches in length, and elephants, mastodons, crocodiles, and

sharks attained a growth still more incredible, farmers should have sufficient ambition and professional pride to look into their own soils, subsoils, and rocks for a home supply of phosphorus, sulphur, potash, and other substances, without which no crop can grow. In the Patent Office Report for 1850 may be found an essay of nearly a hundred pages on the "Study of Soils," in which all the elements of cultivated plants are traced to their source.

Phosphorus and sulphur in combination with iron, as a phosphoret and sulphuret of this metal, often abound in soils-a condition in which they do no good as plant food. The earthy part of every seed of wheat has from seventy-five to eighty per cent. of phosphoric acid and potash as necessary constituents; and while the soil has a plenty of phosphoret of iron and insoluble silicate of potash, the lack of available phosphoric acid and potash often reduces the yield more than one-half. Crops of corn and cotton are also diminished under like circumstances, when their elements, although present, are unavailable. All such lands need marl or lime, by which the phosphorets and sulphurets of iron are changed, or rather made to produce gypsum and bone earth. The phosphate of alumina is decomposed also by lime, yielding a bone phosphate. Sulphur in combination with iron is converted into an acid by lime, with which it unites to form the sulphate of lime, which is best known as gypsum or land plaster. The power of lime to produce both phosphoric and sulphuric acids in soils where neither existed before, gives to the marl beds which extend from the Chesapeake Bay to the Rio Grande great agricultural importance. Lime often eliminates potash and magnesia from their insoluble silicates in a similar manner. Clay roasted with lime gave Dr. Voelcker about twice as much potash to rain-water as that roasted without lime. It is impossible to account for the greatly increased growth of walnut, hickory, and poplar forest trees on our own limestone lands, which contain fourfold more potash and magnesia in their cells and tubes than smaller trees have that grow on similar clays nearly destitute of lime, without conceding the power of this alkaline earth to decompose the silicates of potash and magnesia as derived from their parent rocks, and thereby supply potash and magnesia as well as lime to these magnificent plants. The fertility and general durability of our best lime soils are well known; yet lime is not potash, nor magnesia, nor chlorine, nor soda, nor sulphuric, nor phosphoric acid-all of which appear in our annual crops of grain, grass, and other staples. Lime eliminates these from insoluble minerals as naturally as it forms the stone-like covering of all shell-fish, and the base of all internal skeletons. Its relations to plant life and animal life may be obscure, but they are obviously most intimate and enduring, commencing with some of the oldest sedimentary rocks, which, in the Alleghany range of mountains, Professor Rogers estimates at 40,000 feet in thickness. During all the unknown and apparently almost unlimited geological ages in which these mountains of sea-born rocks have been slowly growing, and serving as the cemetery of expiring species and genera of animals, as well as of individuals, these beings have used lime to cover all their shells, and to give solidity and strength to every bone in their bodies. An element of fertility used by nature so largely and enduringly, thinking farmers will not long neglect.

CALCAREOUS MARLS AND POTASH GREENSANDS.

No owner of a naturally poor clay or sandy farm on the Atlantic slope of the United States can visit the rich calcareous soils to be found in