little influenced by surrounding rocks, and must be lowing principles: First, that plants obtain from a ferstudied independently of them. After a rocky ex- tile soil a variable proportion of their organic food-of posure moulders away under the influence of the their nitrogen probably the greatest part. Secondly, atmosphere, rain, and frost, the débris may be trans- that they require inorganic food of various kinds, and ported to areas more or less distant from the outcrop that they procure this partly from the soil. Thirdly by continuous rains and occasional floods, which will that different species of plants require a special supply not only carry the finer particles to lower levels, but of different kinds of inorganic food, or of the same will slowly move vast quantities of larger fragments kinds in different proportions. Fourthly, that of these to considerable distances. Where a great variety of inorganic substances, one soil may abound or be defistrata outcrop in limited areas, due to high dips and cient in one, and another soil in another; and that, numerous undulations-anticlinals and synclinals-or therefore, this or that plant will prefer to grow on the to a rugged topography, which exposes a number of one or the other accordingly. Mineral manures include strata even with low dips, the soil will unquestion- those mineral substances which may be used for soilably be one of transport, since the materials which enrichment, and which are obtained directly from the form it have been carried from one place to another, earth by simple digging, quarrying, or mining. The as in the valley of the Po, already instanced. In variety of these manures is very great; they are carbosuch cases, however, where the soil may be traced naceous, saline, or calcareous. Peat, although strictly to its mother-rock at no distant point, and where the of vegetable origin, is generally considered one of the transporting agents may have been local phenomena, important mineral manures. When dug up and exthe soil may more reasonably be called one of disinte-posed to the weather it crumbles into powder. Either gration. These agents are operative in a greater or alone or mixed with lime it greatly improves stiff loams less degree according to the rainfall and topographical and clays. When mixed with barnyard manure it infeatures. In many regions they are supplemented by creases its efficiency by absorbing and storing the amlarge rivers, such as the Mississippi, Amazon, Nile, monia which is given off, and which would otherwise Ganges, and Indus, which have frequently overflowed be lost during fermentation. Charred peat is also an their banks, depositing over the adjacent areas large excellent absorbent of the liquids of the_barnyard. masses of rich mud and sand which render their Coal-dust or culm, coal-ashes, and soot have been valleys so fertile. A potent agent in the transport found beneficial for some soils. The two former, spread of soil is found in the wind. The dry and fine sand on cold, stiff clays, cut them, rendering the soil more and silt along the sea-coast are borne away by it and friable. Among the calcareous manures the most imstrewed over the land, forming sandhills and downs of portant are lime and limestone, marls and marly soils. considerable height. "Large areas on the eastern shore When soils in a dry condition contain not less than 5 of the Bay of Biscay and along the coast of Jutland, per cent. or more than 20 per cent. by weight of lime, both of which are exposed to high sea-winds, are they may be called marly. When a soil has some of the covered with wind-blown sands. In the Landes the characteristics of marl, but does not contain as much as advance of the downs is estimated at 66 to 70 feet 5 per cent. of lime, it may be called a sandy, loamy, or every year." The ice-sheets which are now known by clayey-marl soil. If there be more than 20 per cent. geologists with certainty to have covered extended of lime in the soil, it becomes a true calcareous marl. areas of the north temperate zone during the Glacial This classification, which has been proposed by Johnperiod, in moving to the south have carried before them ston, is not adapted to the American marls. Many of large quantities of rock-fragments, sand, and gravel, the rich fertilizing marls from New Jersey contain as which have been dumped along their edges as they low as 1 per cent. of lime, their value depending upon gradually receded, while the ice melted during the variable proportions of phosphoric, sulphuric, and silicic warmer climate of the subsequent epochs. As the ice acid, potash, magnesia, alumina, and iron. The marldisappeared, the material which it dropped would be beds of New Jersey all belong to the Cretaceous formaspread over the country by the resulting water. The tion, and are regularly stratified; the grouping of this northern parts of North America, Europe, and Asia formation shows the relative positions of the marls: are covered in many large districts by soils which have Cretaceous Formation of New Jersey [by Prof. George H. Cook]. been transported by glaciers. A good soil, according to Prof. Ansted, should be composed of nearly equal parts of the three earthssand, clay, and lime; it should contain a certain quantity of decomposing vegetable and animal matter; it should imbibe moisture and give it back to the air without much difficulty; it should have depth sufficient to permit the roots of the plants to sink and extend without coming to rock, to water, or to some injurious earth; the subsoil should be moderately porous, but not too much so; and in case of need the subsoil should be able to improve the soil by admixture with it. It is obvious that soils which have such a varied origin and composition cannot be alike culturable and fertile. Hence, to correct the one by admixture with another, to render this more friable and that more compact, to improve this one by drainage and that by manuring, is essential to successful farming. Sandy soils, though active, soon become exhausted, and are apt to be parched in dry seasons, while, on the other hand, clayey soils, though containing in abundance all the elements for plant-growth, in wet seasons become waterlogged and unworkable. To obtain soils for proper admixture necessitates a geological knowledge of the district. The improvement of soils by this means is of a permanent character, unlike the application of soluble manures, which has to be constantly repeated. According to Prof. Johnston, the methods of improving soils by manures are dependent upon the fol Division. Subdivision. Upper marl-bed....... Ash marl, Middle marl-bed...... Red sand......... Lower marl-bed....... Clay marls. Yellow sand. Dark micaceous clay. Sand marl. Laminated sands, Clayey green sand. Potter's clays, Plastic clays........... These strata extend across the State from Raritan Bay, south of New York, south-west to the Delaware River, extending from Trenton to Salem. The blue shell marl constitutes the principal part of the lower bed. It consists of green sand mixed with fine earth, much of which is carbonate of lime, and is about 16 feet thick. The green marl layer of the middle bed is almost pure green sand, 15 feet thick. The shell layer above it varies from 4 to 7 feet thick. When unchanged it is white, with fossil sea-shells; in the lower two-thirds they consist almost entirely of the Pycnodonta vesicularis, and in the upper third of the country of continental Europe because one-third of its area is an unbroken plain of limestone, with Paris in the centre, and another third of its area consists of almost unbroken delta-deposits, stretching from Marseilles to Bordeaux. At first there was a double France. When its northern and southern halves were united under one government, then united France domidelta soil, and the men of the prairie are becoming the rulers of the republic. Southern Russia is floored with the same black earth, of apparently the same age and of similar origin. Northern India is one immense delta, and on this unbroken plain have lived a succession of empires. At present it supports a population three times as great as that of France. North-eastern China is an immense delta, and its rulers have firmly held their power for four centuries over all the other provinces of the empire. All kinds of soils, even the poorest, can at present be permanently occupied ; populations need not be crowded into the most fertile geological belts; railroads and good roads sow fertility everywhere; and the democratic principle of the greatest good to the greatest number, and more good for all, may be realized." Terebratula harlani. This remarkable bed is developed along the outcrop for 100 miles. The top layer of the middle bed is a mass of crumbled corals, seaeggs, and other calcareous matters, with a small percentage of quartzose sand and scattered grains of green sand. In Salem county it measures 25 feet thick. The upper marl-bed is about 37 feet thick, and is rated as less valuable than the lower beds. The marl is gen-nated Europe. Our Western prairies have virtually a erally dug with spades, or if compact is loosened with grubbing-hoes; it crumbles readily upon exposure to the weather, and is handled as sand. Prof. Cook concludes that (1) The most valuable marls, and those which will best pay the cost of long transportation, are those which contain the largest percentage of phosphoric acid; (2) the most durable marls are those containing most carbonate of lime; (3) greensands containing but little of either phosphoric acid or carbonate of lime become active fertilizers when composted with quicklime; (4) marls which are acid and burning from containing sulphate of iron can be rendered mild and useful as fertilizers by composting with lime; (5) forage crops, grass, clover, etc., are particularly improved by the use of marls. By spreading from 100 to 200 bushels of green marl over a single acre the crop is generally doubled, and sometimes quadrupled. The marl- or phosphate-beds of South Carolina have produced a valuable mineral fertilizer. This formation is of Post Pliocene age, and consists of extensive deposits of fine clay and sand containing incredible numbers of scales, teeth, and bones of fishes. The solid parts of these animals have turned into phosphates, together with other organisms of the vicinity. The bed is over thirty miles long, and is widest in the vicinity of Charleston. The value of these marls is almost entirely dependent upon the amount of the phosphate of lime which they contain. A crystallized variety of the phosphate of lime under the name of APATITE (q. v.) is frequently obtained from veins in the older rocks. A more massive variety, known as phosphorite, is more abundantly found. In the greensand and crag formations of England and the greensands of France phosphatic nodules, concretions, round bones, and coprolites, or fossil excrements, are found in beds from a few inches to several feet thick, and when moderately pure contain 50 per cent. of phosphate of lime. Lime, which has been called the "basis of all good husbandry," is probably the most valuable, and certainly the most available and extensively used, of all mineral manures. The value of lime as a fertilizer, and of other mineral manures, depends much upon their composition; in this the agriculturist must seek the aid of the chemist. The application of lime increases the fertility of soils in which it does not abound, and enriches moist soils and those which contain inert vegetable matter. The value of many animal manures is greatly increased by the use of lime. In addition to these mineral manures, a number of saline substances have recently been employed with wonderful advantage. Among these may be mentioned sulphate of ammonia, carbonates, silicates, and nitrates of potash and soda, common salt, and sulphate of magnesia. The drainage and irrigation of soils are rendered necessary by the superabundance or scarcity of water, which in turn is directly dependent upon the geological structure of the rocks, of any area specially considered. In speaking of the bearing of geology upon agriculture and the importance of good soils, Prof. Lesley says: "Good soil has always been essential to civilization. The best soil is that of river-deltas, and on these have sprung up all the mighty empires of history. The next best soil is that which covers the limestone rocks. Where continents are crossed by belts of limestone soil, population is dense and intelligent and the map is studded with villages and large towns. France became the most powerful and enlightened Re Works to be consulted: Johnston's Lectures on the Appli- CHAPTER III. The development in the efficiency of agricultural implements and machinery within the last quarter of a the earth's tillage. As a single example, it is estimated century has been without a parallel in the history of that in the United States the mower and reaper in the season of the harvest now saves the labor of 2,000,000 men. In this article, in which it is attempted only to review hastily the principal improvements made on the imperfect tools of former years, and to describe the most valuable labor-saving appliances of the present time, they will be taken up in the order in which they season, beginning with (1) implements of tillage; (2) are used during the successive stages of work in the implements for planting and sowing; (3) implements for cultivation; (4) machines for harvesting crops; ̧ (5) thrashers and separators; (6) steam-, water-, and wind powers. (1.) Implements for Tillage. The Plough.-This implement, although introduced into use thousands of years ago, has never yet been superseded; its simplicity has maintained its position. Although made of several parts, yet these are firmly bolted together and made into a compact implement capable of receiving without harm the sudden blows from stones in the soil or resisting the concussion of other obstructions. Many attempts have been made to perform the work of the plough with more complex contrivances and rotary spaders, but they have been so easily deranged or bent by use in hard soils that in all cases they have been thrown aside, except in sandy or alluvial districts which are free from stones. FIG. 1.-Kooloo Plough. The ploughs of the ancients and of partly civilized modern peoples will not compare for a moment with the best improved steel or chilled-iron ploughs made in this plough," generally in use in this country in the early part of the present century, is still remembered by old farmers. It had a wooden mouldboard with an iron share, and frequent journeys were made by the farmers to the neighboring blacksmith to sharpen the points worn dull by use. Jethro Wood, the inventor of the cast-iron plough, was the first to give it a form for general introduction, and the shape of his mouldboard has been scarcely improved in the best formed ploughs of the present time, as represented in fig. 4. FIG. 4.-Modern Plough. The cast-iron plough, when first manufactured for sale, was placed in market with the rough surface to the mouldboard as it came from the founder's moulds, and days were required in adhesive soils, by frequent scouring with the hand while at work in the field, to give it a bright surface and to cause the furrow-slice to glide freely over its face. A great advance was subsequently made by using steel for the mouldboard, causing less adhesion of the soil to its surface. More recently, the chilling process is applied to the whole surface of the mouldboard, and the late improvements in this process render the metal so hard that a file will scarcely make any impression on it, while full strength is secured. The efficiency and durability of the improved ploughs, as now manufactured in numbers counted by hundreds of thousands in the United States, are worth annually to the farming interests many millions of dollars. Construction of Ploughs.-There are two important requisites to every good plough: (1) It must have a light draught for the amount of work it performs, and must run with steadiness and at uniform depth; (2) the character of the work must be as perfect as practicable in inverting the sod, burying vegetable growth, and pulverizing the soil as it is thrown over, instead of laying it in a heavy, solid mass. Under the first requisite the two principal sources of resistance must be considerednamely, the friction on the bottom and sides, and the resistance of the earth against the cutting edge. Experiments in this country and in England have shown that the friction is about 35 per cent. of the whole force required to draw the plough, while about 55 per cent., or more than one-half, is consumed in cutting the earth or separating the furrow-slice from the solid land. The remaining 10 per cent. is required for lifting the furrow-slice and laying it over. These figures-which, however, vary with different soils-show that it is most important to maintain a sharp cutting edge to the point or share. Hence this edge is made of the hardest material, chilled iron being found best. Where stones or other obstructions exist in the soil, or where it is so hard as to offer much resistance, it is necessary that the line of the cutting edge form an acute angle with the land-side, making a sharp wedge for more freely crowding these obstructions aside-for the same reason that a sharp boat runs most easily through water. In such stony or gravelly land the tenacity of the soil to be overcome is not great, and a sharp edge, like that But where the soil is of a knife, is less essential. filled with fibrous roots, as on the Western prairies, a and hence the frequent use of the rasp or file in the keen edge to cut them is of the greatest importance, field to maintain it. The form of the mouldboard may vary with its purposes. On a heavy or hard soil it should have such a twist as to produce pulverization in the act of inversion. This part of the plough may have an almost endless variety of forms, the best of which may be determined by actual trial in different soils-ease of draught and good work being the two essentials. The Operation of Ploughing.-An expert ploughman will attach the team as near to the plough as practicable for them to turn the corners without the whiffletrees striking their heels. The nearer the horses are to the plough, the less the friction is on the sole of it. A pair of horses attached as leaders perform much less effective work than the other two nearest to it; and three horses abreast are nearly as effective as four geared in pairs. By adjusting the traces, and the clevis at the end of the beam, the ploughman regulates both the depth and the width of the furrow. If the furrow-slice is too narrow for its depth, it will be crowded aside without turning over. A variation of an inch or two in width or depth will make the difference between good and bad ploughing. A well-adjusted plough will run so steadily as often to go some distance without being held. On the contrary, when ploughing in adjustment of the plough, or possibly the fault may be partly in the implement itself. Sulky Ploughs.-These implements have two considerable advantages over the common plough-in the ease to the ploughman, and in the reduced friction by the wheels bearing the weight of the plough and of the furrow-slice, instead of dragging this weight on the sole of the plough in the furrow. By the use of levers the ploughman controls the depth of the furrow and the width of the slice. An example of these, the Buckeye sulky plough, is represented in fig. 5. The wheels and attachments may be used for any plough, turning the furrow either to the right or to the left, and two or three horses may be used. plough, without throwing the soil to the surface. The mellow bed of earth thus made deeper absorbs and holds water like a sponge, and gives it off in time of drought. It allows a deeper range for the roots. Rootcrops in dry seasons have sometimes been doubled by its use. Subsoil ploughing is of little value on light and porous soils with loose subsoils. It is specially beneficial for firm soils which have an impervious crust below. Although the practice is an old one, there are important requisites in the construction of the implement not always understood. Fig. 7 represents a common form, the wedge-form share at the base for loosening up the hard subsoil being supported by a double shank connected with the beam. Sometimes, instead of the double shank, there is a single broad one, which works well in non-adhesive earth, but in strong clay soils in a moist condition the broad face of the shank adheres to the earth, greatly increasing the draught, and sometimes stopping the team altogether. In such soils, to reduce the friction to the lowest practicable amount, the shank should be made as narrow as possible, like that represented in fig. 8, the required strength being given by braces. When broad shanks have been used in clay soils, the operation has been so difficult that subsoil ploughing has been pronounced impracticable and a failure. FIG. 6.-Casaday Sulky Plough. The Casaday sulky plough (fig. 6) has a distinct peculiarity in omitting altogether the land-side of the plough, an inclined wheel pressing against the side of the furrow and holding the plough firmly in position as it passes onward. It will be seen that the friction on the sole of the plough and that against the land are both obviated by the two wheels which bear the weight; and the furrow-slice is maintained of a perfectly uniform width without care on the part of the driver. Ease to the ploughman and lightness of draught have already been stated as the merits of sulky ploughs. The drawbacks are increased cost-more than double the cost of ploughs alone-and their more cumbersome shape. While, therefore, they have proved advantageous on large farms, and particularly on the broad plains of the West, they are less valuable on farms of moderate or small size or where the land is uneven or contains many obstructions. FIG. 8. Trench-ploughing should not be confounded with subsoiling. The former makes a deep furrow, but throws the soil to the surface; the latter merely loosens the soil, leaving it below. Trench-ploughing is valuable where the subsoil possesses fertilizing elements which are valuable when mixed with the earth at the surface. It is performed either with a common plough, or with a plough of similar form but admitting of greater depth of work. The double Michigan is one of the best forms of the trench plough. It often happens that the subsoil plough may perform a useful office by loosening the earth to precede the trench plough and give it greater depth. As the main object in using the subsoil plough is to loosen the earth without lifting it, the share which performs the loosening must be in the form of a wedge. If the subsoil is hard and not adhesive, the wedge should be quite acute, so as to enter the hard material with least resistance; but if the subsoil is stony, the wedge should be shorter. Subsoil ploughs are to be selected, therefore, for their adaptation to the different soils in which they are used. FIG. 7.-Common Subsoil Plough. Subsoil Ploughs.-The common plough inverts and pulverizes the soil down to a depth of six or eight inches, and by repeating the operation year after year the pressure of the sole of the plough in the bottom of the furrow gradually forms a hard crust, which is detrimental to the extension of the roots of plants below that depth, and prevents the ascent of the moisture from the earth below. When heavy rains fall the shallow bed of mellow earth is soaked and flooded with the excess of water. To prevent these difficulties the subsoil plough is used. It is made in such a form as to loosen the subsoil several inches deeper by running in the bottom of the furrow made with the common FIG. 9.-Ditching Plough. The ditching plough is a useful implement, a modification substantially of the subsoil plough. After trials of various forms of complicated machinery for ditching, the experience thus gained favors the use of | by making the smaller or paring plough of less size, simple ploughs of the kind shown in figs. 9, 10. These now termed a skim plough or skim coulter, the whole can be made to go down, by successive passings, to a plough being known as a jointer." Fig. 12 represents depth of three feet, loosening the hard subsoil and the Wiand plough, made in this form. obviating the use of the pick. The loosened earth is thrown out by hand. Under good management and favorable circumstances, it reduces the expense of cutting the ditch to less than one-half what it would cost by hand-labor. FIG. 10.-Another form of Ditching Plough. FIG. 12.-Wiand Plough. Reversible Ploughs.-A form of the plough by which the share and mouldboard may be readily changed from one side to the other, or to the left or to the right, termed also the swivel or side-hill plough, is specially adapted to ploughing the sloping sides of hills by changing the mouldboard at the beginning of each furrow, and turning every furrow down hill. These ploughs may be used also on level land, obviating the ifications, one of the best is represented by fig. 13, making of any dead furrow. Among the various mod Appendages to the Plough.-The simpler the plough and the fewer its appendages, the better, provided it runs equally well. Sometimes, however, the simplerifications, additions give important advantages. Among these is the wheel for regulating the depth, placed under the forward end of the beam, as shown in fig. 10. Accurate experiments have shown that the wheel not only gives better ploughing with moderate skill, but also slightly reduces the draught. It gives uniformity to the depth of the furrow and equalizes the labor of the team. The wheel should sustain little pressure, that the line of draught may be nearly straight. Another useful appendage where a heavy growth of vegetable matter is to be turned under is the chain and weed-hook. Crops of clover, rye, or other green manures may be completely and easily buried by attaching a large chain to connect the whiffletree to the plough in such a manner as to gather and sweep under the entire growth in front of the furrow-slice. The same result is more neatly performed with the weed-hook, which is an iron rod attached to the plough-beam and extending backward in an oblique direction just above the furrow-slice, so as to lay the vegetable growth flat just before it is turned under. FIG. 13.-Oneonta Clipper. known as the Oneonta clipper. Like other side-hill ploughs, the change in the mouldboard is effected by swinging it around and under the implement. The hook or latch connected with the mouldboard is operated by a tread of the foot of the ploughman, turning it for the next furrow without taking his hands from the handles. It is so arranged that the ploughman may walk with both feet in the furrow. Each change of the mouldboard and share brings the coulter into position. Other forms of the swivel plough are simpler in construction, but require more attention on the part of the ploughman in changing at the ends of the furrows. FIG. 11.-Double Michigan Plough. The Double Michigan Plough.-A plough under this name was introduced more than thirty years ago, and proved of great efficiency for certain purposes. It consisted of a large common plough, with a smaller plough attached to the beam forward of the large one, about one-half or one-third, its size (fig. 11). The plough was set deep enough for the small plough to cut about three or four inches deep, so that the surface was inverted with this smaller plough and thrown into the bottom of the previous furrow. The large plough, following, turned up the under soil and threw its heavy furrow-slice over on the previous small furrow-slice, and buried it deeply under. This plough was especially valuable for inverting grass-sod, the smaller plough paring off the surface, and the larger one burying the grass so deep that it could not sprout up to the surface. The grass-field thus ploughed presented a deep, mellow surface, with none of the common appearance of inverted sod. An objection to this plough was the force required to draw it, which was at least double that for the common plough, the larger ones usually running nearly or quite a foot deep. The form has been modified, therefore, FIG. 14.-Plough and Pulverizer. Sackett Plough and Pulverizer.-This implement for combining the operations of ploughing and fine pulverization has been recently invented and brought into use (fig. 14). Like the original double Michigan and the later jointer plough, it has a smaller forward plough or mouldboard, which removes a few inches of the top soil, which is pressed down or crushed by the open wheel into the bottom of the previous furrow. |