who discovered these rounded water worn nodules in the crag formation, thought, from their peculiar form, and the frequency of sharks' teeth and other organic remains found in them, that they were the dung of a former generation of animals. He therefore called them coprolites, and, though this opinion is now admitted erroneous, yet they still retain the name. The upper and lower green sand formation also contain nodules of phosphate of lime, which have not been used to any great extent, owing to the superior facilities of working the beds of the crag in Suffolk and Essex, where they are found in unlimited quantities. The mean composition of the Suffolk coprolites, from several analyses made in the Rothamsted laboratory, may be estimated at Bone phosphate of lime, with a little phosphate of iron... Matter insoluble in H C I.. 55 25 20 100 There is a mineral phosphate of lime, apatite, which has been known to exist in Estremadura, in Spain, for a long period. Dr. Daubeny and Captain Willington visited the locality a few years since, for the purpose of ascertaining whether it existed in sufficient quantities for agricultural purposes. They describe it as a vein many feet thick, extending over miles of country, but situated in a locality where it will have to be transported for a long distance upon the backs of mules. Some tons of this apatite were imported into England, but the price was necessarily much too high for commercial purposes. It is a hard crystallized rock, of a yellowish-white or greenish color, and composed, according to Dr. Daubeny, of— Professor Way, in a small portion of this mineral, found 85 per cent. of phosphate of lime. It resembles in many respects the phosphate of lime found at Crown Point, of which we shall speak further on. It contains no carbonate of lime; but the 14 per cent. of fluoride of calcium is a great objection, as by it the effective strength of the sulphuric acid is considerably reduced, 100 pounds fluoride of lime requiring 103 pounds real sulphuric acid to convert it into sulphate of lime. The escape, too, of the fluorine gas in such large quantities is very obnoxious, and renders the manufacture of apatite into super-phosphate of lime not only disagreeable, but difficult. The process of manufacturing super-phosphate of lime in the principal factory in England is as follows: The stones (for such the coprolites are to all appearance) are first reduced to a powder about the fineness of corn-meal. This is accomplished by passing them through two cast iron rollers about eighteen inches in diameter. The first rollers are placed above the second pair, which are set close together, reducing the stones to about the size of peas. They are then passed through millstones similar to those used to grind wheat, but driven with greater speed. The powder is then placed in a large iron vessel lined with lead, having within it a number of paddles revolving with great rapidity; water sufficient is added to convert it into a thick cream; sulphuric acid is now added, and the mixture agitated with the paddles, similarly to the process of churning, for about five minutes. The semi-fluid mass is then thrown out and placed in a heap; and such is the heat generated by the process, that in a few days it will become solid, and may be placed in bags. In this factory fifteen hundred tons are usually placed in a heap, which will remain hot for months; the heat materially aiding the decomposition of the phosphates. Bones alone do not make a solid manure when mixed with sulphuric acid; but if a portion of the mineral phosphate of lime is used with them, they form a very valuable and efficacious manure, which can be transported in bags and sown without admixture with ashes. As before stated, the Spanish phosphate of lime (apatite) is too expensive to use for agricultural purposes. Yet Mr. Lawes obtained a quantity and made a few experiments with it; which, as this substance closely resembles the American phosphate of lime, it may be interesting to give: 3 1 Three cwt. finely-ground apatite... ... 152 7 142 It is seen that three hundred and thirty-six pounds of undecomposed apatite, though reduced to the finest powder, gave an increase of only sixteen and three quarters cwt. of turnip bulbs per acre; while two hundred pounds manufactured into super-phosphate of lime gave an increase over the unmanured acre of four tons and eleven and a half cwt., and more than double that of the undecomposed apatite. The acre dressed with super-phosphate of lime from calcined bones gives a slight increase over the decomposed apatite, but not in a corresponding ratio with the increased quantity applied. From this we may conclude that mineral phosphate of lime, provided it contain the same amount of phospheric acid and no deleterious substances, is just as good as that obtained from bones when both are made into super-phosphate of lime. If both are applied in their undecomposed state, the calcined bones appear to be slightly soluble, and to have a better effect than the ground apatite. The value of phosphate of lime in England in such substances as apatite, coprolites, &c., is twenty-four cents per ton for every one cent of bone-earth phosphate which they contain. Thus, if a substance contains eighty per cent. phosphate of lime, it will be worth $19 20 per ton; if ninety, it will be worth $21 60 per ton in any British port in its natural state. If, however, it contains but a small per centage of phosphate of lime, and considerable carbonate or fluoride of lime, its value, calculated on the per-centage of phosphate of lime, will be considerably reduced, inasmuch as the substances have to be neutralized before the sulphuric acid will act upon the lime. The price of boiled bones is $21 per ton; or, calculating them to contain sixty per cent. of phosphate of lime, $7 per ton higher than they would be worth according to the above method of valuation; but it must be remembered they contain some organic matter which, especially the nitrogen, is very valuable. The wholesale price of super-phosphate of lime in London, manufactured from the Suffolk coprolites which have been described, is $20 per ton; that manufactured from calcined bones, Saldanha Bay guano, &c., is worth $33 per ton. We must now consider, as being more interesting to our farmers, the value of the recent discovery of unlimited, almost pure, phosphate of lime in the United States, especially that of Crown Point, Essex county, New York, and that of the New Jersey Zinc Company. The former, we believe, was discovered by Professor Emmons, of Albany, and is sup. posed to be the richest vein of phosphate of lime in the world. Some selected specimens have been found to contain ninety per cent. of boneearth phosphate. Several barrels have been sent to England for trial, where, provided it can be furnished cheap enough, it will be largely used. The samples sent there do not appear to have been well selected, and contained considerable quartz; which, as the facilities for working the mine increase, will be avoided. A large lump of it was broken up, and a fair specimen taken for analysis by Professor Way, with the following result: Composition of the American Phosphate of Lime. Bituminous matter and water expelled at red-heat.... Phosphoric acid, equal to 62. 27 bone earth phosphate. 0.69 16.79 9.65 30.20 40.10 6.47 1.08 0.08 0.20 0.25 trace. 3.49 100.00 This is a much superior article to the Suffolk coprolites, though I believe the above is not so good as the average of that obtained from the same source. It is not so hard, and requires but little labor to pulverize it; and hence it will be manufactured into super phosphate of lime at a much less cost of labor and machinery than the coprolites now used in England. The absence, too, of carbonate of lime, of which twenty-five per cent. is found in the coprolites, is a very great advantage, requiring a much less quantity of sulphuric acid for its manufacture into superphosphate of lime. It would be useless to give the amount of sulphuric acid needed for the conversion of this article into super-phosphate of lime, deduced from the above analysis; for, though there can be no doubt that the figures represent the true composition of the sample analyzed, yet they considerably underrate the amount of phosphate of lime which a well selected quantity would contain; and it will be easy for any one to calculate the quantity of acid best to use (the amount of phosphate of lime and lime being known) from the date before given. But it must be borne in mind that, when speaking of sulphuric acid, I have referred to the pure anhydrous acid, and not to oil of vitriol, or the commercial sulphuric or brown acid. At the end of this paper will be found a table of Dr. Acre's, showing the amount of real sulphuric acid contained in oil of vitriol of various densities. The "chamber," or "brown acid," of the manufactures of Sp. Gr. 1.7 is the cheapest and most generally used article for the man facture of super-phosphate of lime; one hundred pounds of this acid contain sixty-five pounds of real sulphuric acid; its wholesale price in London is eleven mills per pound; there being but little demand for this article at present; the price is much higher; but as the demand increases it will doubtless be manufactured on a large scale, at a much less cost; it is now sold by the car boy, in the principal cities, at 2 to 3 cents per pound; it is not so dangerous to use as most people imagine, and, if ordinary care is exercised, nothing need happen worse than an occasional blotch of the clothes and a stain on the boots, &c. It is not probable that the mineral phosphate will be manufactured by the farmers themselves; so that I need not dwell on it any longer. But bones are of great importance, and at the command, to some extent, of every farmer, who would find it much to his interest to convert them into manure for his soil, rather than let them lie bleaching in the sun in some out-of-the-way place, shedding their odor on the desert air. Bones, if finely ground, will do good if applied in their natural state; but their benefit is small and slow; and it is best to decompose them with sulphuric acid, especially as a manure for turnips, rutabagas, young trees, cabbage, beets, &c. To use acid economically the bones should always be finely ground; one hundred pounds of fresh bones contain Phosphate of lime.. ... ... 4.5 4.0 Now, to convert these forty-five pounds phosphate into bi-phosphate of lime, it will be found from data previously given (page 308) that we have got to abstract 14 pounds of lime by sulphuric acid, converting it into sulphate of lime. To do this, twenty pounds of real sulphuric acid would be required, or 313 pounds of brown or chamber acid, (Sp. Gr. 1.7;) but before the acid will act on the phosphate the carbonate of lime must be converted into a sulphate; to do this 34 pounds real acid will be neutralized, or five pounds of the brown acid, (Sp. Gr. 1.7.) We have, therefore, in the manufacture of super-phosphate of lime from bones, to put about twenty-four pounds of real sulphuric acid, or thirtyseven pounds of brown acid, (Sp. Gr. 1. 7,) to one hundred pounds of the bone dust. A good method for the farmer to make his own super-phosphate of lime, is to get a large tub, or end of a cask, place in it the quantity of bone dust that can be best worked at a time-say 60 pounds; sufficient water should then be added just to wet all the bones; let this be stirred till the dust is all wet, and then add the proper quantity of acid, 22 pounds, (Sp. Gr. 1.7.) When mixed, it can be thrown into a heap on the floor, and the process repeated. The operation should be done expeditiously, and the larger the heap the better, as the heat engendered during the process materially assists the acid in decomposing the phosphate. Some farmers think the above method too tedious, and prefer placing the whole amount of dust in a large heap on a wooden floor; wet it with water and apply the acid in small quantities, repeatedly turning the heap and applying the acid till the proper quantity is used. This plan does not require so much labor, but the farmer insures a more equally mixed and better manufactured article. When properly manufactured it will be sufficiently dry to sow by hand without any absorbent substance, but if drilled, as it always should be when used as a manure for turnips, it is necessary to mix with it some dry materials-such as coal ashes, dry, leached ashes, saw dust, peat, &c.; but on no consideration let lime, wood-ashes, or any other caustic alkalies or alkaline earth be used, for a reaction immediately takes place, and the bi-phosphate is converted back again into the bone earth phosphate of lime, and all the labor has been in vain. Super-phosphate of lime, manufactured from fresh bones, is doubtless much the best article, if employed as a manure for wheat, corn, Timothy,. &c., as, besides the phosphoric acid, it contains considerable nitrogen. Fresh bones contain 5 per cent. of nitrogen, which, at the present value of ammonia, in guano or sulphate of ammonia, would make bones worth, for this element alone, 50 cents per 100 pounds; and, according to the estimate of Mr. Lawes-that 5 pounds of ammonia will produce an extra bushel of wheat-we might expect a little more than a bushel by the application of 100 pounds of fresh bones. The super-phosphate manufactured from the apatite, or, as Professor Emmons named it, the eupyrchroite, would be a purely mineral manure, and would have no beneficial effect on wheat, unless the soil was agriculturally deficient of phosphoric acid, and in that case it would only raise the produce to the natural or normal produce of the soil-say 15 to 20 bushels of grain. In relation to the discovery of the mineral phosphate in this country, Professor Johnston has said, "American farmers, in general, have not the knowledge to appreciate the value of such a manuring substance as this, nor the ability to purchase it, when manufactured into super-phosphate of lime; the discovery, therefore, will be a boon for the present to both countries. It will make more abundant and cheap the means of fertility, which our soils require, while, by supplying a new article of traffic, only salable in Great Britain, it will form a new bond of connexion between our kindred nations." The English farmers are most loudly and justly complaining of high rents, high taxes, and low prices in consequence of free trade; and it is American competition that they must fear. They think that, with a good climate, admirable means of transportation, both natural and artificial, a rich, new soil, which can be had comparatively for nothing, the American farmers will inundate their market with cheap wheat, corn, beef, |