Muscular power still carries out all the most laborious work of the farm and of the garden—work which, of course, consists, in the main, of turning the land over and breaking up the sods. In the operations of ploughing, harrowing, rolling, and so forth, the agency almost exclusively employed is the muscular power of the horse guided by man-power; with the accompaniment of a very large and exhausting expenditure of muscular effort on the part of the farmer or farm labourer. On the fruit and vegetable garden the great preponderance of the power usefully exercised must, under existing conditions, come direct from the muscles of men. Spade and plough represent the badges of the rural workers' servitude, and to rescue the country residents from this old-world bondage must be one of the chief objects to which invention will in the near future apply itself.

The miner has to a very large extent escaped from the thraldom of mere brute-work, or hardening muscular effort. He drills the holes in the face of the rock at which he is working by means of compressed air or power conveyed by the electric current; and then he performs the work of breaking it down by the agency of dynamite or some other high explosive. Much heavy bodily labour, no doubt, remains to be done by some classes of workers in mines; but the significance of the march of improvement is shown by the fact that a larger and larger proportion of those who work under the surface of the ground, or in ore-reduction works, consists of men who are gradually being enrolled among the ranks of the more highly skilled and intelligent workers, whose duty it is to understand and to superintend pieces of mechanism driven by mechanical power.

In farming and horticulture the field of labour is not so narrowly localised as it is in mining. Work representing an expenditure of hundreds of thousands of pounds may be carried out in mines whose area does not exceed two or three acres; and it is therefore highly remunerative to concentrate mechanical power upon such enterprises in the most up-to-date machinery. But the farmer ranges from side to side of his wide fields, covering hundreds, or even thousands, of acres with his operations. He is better situated than the miner in respect of the economical and healthy application of horse-power, but far worse in regard to the immediate possibilities of steam-power and electrically-conducted energy. No one can feed draught stock more cheaply than he, and no one can secure able-bodied men to work from sunrise till evening at a lower wage.

Yet the course of industrial evolution, which has made so much progress in the mine and the factory, must very soon powerfully affect agriculture. Already, in farming districts contiguous to unlimited supplies of cheap power from waterfalls, schemes have been set on foot for the supply of power on co-operative principles to the farmers of fertile land in America, Germany, France, and Great Britain. One necessity which will most materially aid in spurring forward the movement for the distribution of power for rural work is the requirement of special means for lifting water for irrigation, more particularly in those places where good land lies very close to the area that is naturally irrigable, by some scheme already in operation but just a little too high. Here it is seen at once that power means fertility and consequent wealth, while the lack of it—if the climate be really dry, as in the Pacific States of America—means loss and dearth. But the presence of a source of power which can easily be shifted about from place to place on the farm for the purpose of watering the ground must very soon suggest the applicability of the same mechanical energy to the digging or ploughing of the soil.

It is from this direction, rather than from the wide introduction of steam-ploughs and diggers, that the first great impetus to the employment of mechanical power on the farm may be looked for. The steam-plough, no doubt, has before it a future full of usefulness; and yet the slow progress that has been made by it during a quarter of a century suggests that, in its present form—that is to say while built on lines imitating the locomotive and the traction-engine—it cannot very successfully challenge the plough drawn by horse-power. More probable is it—as has already been indicated—that the analogy of the rock-drill in mining work will be followed. The farmer will use an implement much smaller and handier than a movable steam-engine, but supplied with power from a central station, either on his own land or in some place maintained by co-operative or public agency. Just as the miner pounds away at the rock by means of compressed air or electricity, brought to his hands through a pipe or a wire, so the farmer will work his land by spades or ploughs by the same kind of mechanical power. The advantages of electrical transmission of energy will greatly favour this kind of installation on the farm, as compared with any other method of distribution which is as yet in sight.

For the ploughing of a field by the electric plough a cable will be required capable of being stretched along one side of the area to be worked. On this will run loosely a link or wheel connected with another wire wound upon a drum carried on the plough and paid out as the latter proceeds across the field. For different grades of land, of course, different modes of working are advisable, the ordinary plough of a multifurrow pattern, with stump-jumping springs or weights, being used for land which is not too heavy or clayey; a disc plough or harrow being applicable to light, well-worked ground; and the mechanical spade or fork-digger—reciprocating in its motion very much like the rock-drill—having its special sphere of usefulness in wet and heavy land. In any case a wide, gripping wheel is required in front to carry the machine forward and to turn it on reaching the end of the furrow. The wire-wound drum is actuated by a spring which tends to keep it constantly wound up, and when the plough has turned and is heading again towards the cable at the side of the field, this drum automatically winds up the wire. So also when each pair of furrows has been completed, the supply-wire is automatically shifted along upon the fixed cable to a position suitable for the next pair.

Not only in the working, but also in the manuring, of the soil the electric current will play an important part in the revolution in agriculture. The fixing of the nitrogen from the atmosphere in order to form nitrates available as manure depends, from the physical point of view, upon the creation of a sufficient heat to set fire to it. The economic bearings of this fact upon the future of agriculture, especially in its relation to wheat-growing, seemed so important to Sir William Crookes that he made the subject the principal topic of his Presidential Address before the British Association in 1898.

The feasibility of the electrical mode of fixing atmospheric nitrogen for plant-food has been demonstrated by eminent electricians, the famous Hungarian inventor, Nikola Tesla, being among the foremost. The electric furnace is just as readily applicable for forcing the combination of an intractable element, such as nitrogen, with other materials suitable for forming a manurial base, as it is for making calcium carbide by bringing about the union of two such unsociable constituents as lime and carbon.

Cheap power is, in this view, the great essential for economically enriching the soil, as well as for turning it over and preparing it for the reception of seed. Nor is the fact a matter of slight importance that this power is specially demanded for the production of an electric current for heating purposes, because the transmission of such a current over long distances to the places at which the manurial product is required will save the cost of much transport of heavy material.

The agricultural chemist and the microbiologist of the latter end of the nineteenth century have laid considerable stress upon the prospects of using the minute organisms which attach themselves to the roots of some plants—particularly those of the leguminaceÆ—as the means of fixing the nitrogen of the atmosphere, and rendering it available for the plant-food of cereals which are not endowed with the faculty of encouraging those bacteria which fix nitrogen. High hopes have been based upon the prospects of inoculating the soil over wide areas of land with small quantities of sandy loam, taken from patches cultivated for leguminous plants which have been permitted to run to seed, thus multiplying the nitrogen-fixing bacteria enormously. The main idea has been to encourage the rapid production of these minute organisms in places where they may be specially useful, but in which they do not find a particularly congenial breeding ground.

The hope that any striking revolution may be brought about in the practice of agriculture by a device of this kind must be viewed in the light of the fact that, while the scientists of the nineteenth century have demonstrated, partially at least, the true reason for the beneficial effects of growing leguminous plants upon soil intended to be afterwards laid down in cereals, they were not by any means the first to observe the fact that such benefits accrued from the practice indicated. Several references in the writings of ancient Greek and Latin poets prove definitely that the good results of a rotation of crops, regulated by the introduction of leguminous plants at certain stages, were empirically understood. In that more primitive process of reasoning which proceeds upon the assumption post hoc, ergo propter hoc, the ancient agriculturist was a past-master, and the chance of gleaning something valuable from the field of common observation over which he has trod is not very great.

Modern improvements in agriculture will probably be, in the main, such as are based upon fundamental processes unknown to the ancients. By the word "processes" it is intended to indicate not those methods the scientific reasons for which were understood—for these in ancient times were very few—but simply those which from long experience were noticed to be beneficial. Good husbandry was in olden times clearly understood to include the practice of the rotation of crops, and the beneficial results to be expected from the introduction of those crops which are now discovered to act as hosts to the microbes which fix atmospheric nitrogen were not only observed, but insisted upon.

From a scientific point of view this concurrence of the results of ancient and of modern observation may only serve to render the bacteriology of the soil more interesting; but, from the standpoint of an estimate of the practical openings for agriculture improvements in the near future, it greatly dwarfs the prospect of any epoch-making change actually founded upon the principle of the rotation of crops. It is, indeed, conceivable that fresh light on the life habits of the minute organisms of the soil may lead to practical results quite new; but hardly any such light is yet within the inventor's field of vision.

This view of the limited prospects of practical microbiology for the fixing of nitrogen in plant-food was corroborated by Sir William Crookes in the Presidential Address already cited. He said that "practice has for a very long time been ahead of science in respect of this department of husbandry". For ages what is known as the four course rotation had been practised, the crops following one another in this order—turnips, barley, clover and wheat—a sequence which was popular more than two thousand years ago. His summing up of the position was to the effect that "our present knowledge leads to the conclusion that the much more frequent growth of clover on the same land, even with successful microbe-seeding and proper mineral supplies, would be attended with uncertainties and difficulties, because the land soon becomes what is called clover-sick, and turns barren".

In regard to any practical application of microbe-seeding, the farmers of the United Kingdom at the end of the nineteenth century had not, in the opinion of this eminent chemist, reached even the experimental stage, although on the Continent there had been some extension of microbe cultivation. To this it may fairly be added that some of the attention attracted to the subject on the Continent has been due to the natural tendency of the German mind to discover fine differences between things which are not radically distinct. Under the title of "microbe-cultivation" the long-familiar practice of the rotation of crops may to some continental enthusiasts seem to be quite an innovation!

In the electrical manures-factory the operations will be simply an enlargement of laboratory experiments which have been familiar to the chemist for many years. Moist air, kept damp by steam, is traversed by strong electric sparks from an induction coil inside of a bottle or other liquor-tight receiver, and in a short time it is found that in the bottom of this receptacle a liquid has accumulated which, on being tested, proves to be nitric acid. There is also present a small quantity of ammonia from the atmosphere. Nitrate of ammonia thus formed would in itself be a manure; but, of course, on the large scale other nitrates will be formed by mixing the acid with cheap alkalies which are abundant in nature, soda from common salt, and lime from limestone.

In this process the excessive heat of the electric discharge really raises the nitrogen and oxygen of the atmosphere to a point of temperature at which chemical union is forced; or, in other words, the nitrogen is compelled to burn and to join in chemical combination with the oxygen with which formerly it was only in mechanical mixture. When nitrogen is burning, its flame is not in itself hot enough to ignite contiguous volumes of the same element;—otherwise indeed our atmosphere, after a discharge of lightning, would burn itself out!—but the continuance of an electric discharge forces into combination just a proportionate quantity of nitrogen. Practically, therefore, manure in the future will mean electricity, and therefore power; so that cheap sources of energy are of the greatest importance to the farmer.

With dynamos driven by steam-engines, the price of electrically-manufactured nitrate of soda would, according to the estimate of Sir William Crookes, be £26 per ton, but at Niagara, where water power is very cheap, not more than £5 per ton. Thus it will be seen that the cheapness of power due to the presence of the waterfall makes such a difference in the economic aspects of the problem of the electrical manufacture of manurial nitrates as to reduce the price to less than one-fifth! It must be remembered that at the close of the nineteenth century the electric installation at Niagara is by very many persons looked upon as being in itself in the nature of an experiment, but at any rate there seems to be no room for doubt that the cost of natural power for electrical installations will very soon be materially reduced. Even at the price quoted, namely £5 per ton, the cost of nitrate of soda made with electrically combined atmospheric nitrogen compares very favourably with commercial nitrates as now imported for agriculture purposes. "Chili nitrate," in fact, is about fifty per cent. dearer.

When wave-power and other forms of the stored energy of the wind have been properly harnessed in the service of mankind, the region around Niagara will only be one of thousands of localities at which nitrogenous manures can be manufactured electrically at a price far below the present cost of natural deposits of nitrate of soda. From the power stations all around the coasts, as well as from those on waterfalls and windy heights among the mountains, electric cables will be employed to convey the current for fixing the nitrogen of the air at places where the manures are most wanted.

The rediscovery of the art of irrigation is one of the distinguishing features of modern industrial progress in agriculture. Extensive ruins and other remains in Assyria, Egypt, India, China and Central America prove beyond question that irrigation played a vastly more important part in the industrial life of the ancients than it does in that of modern mankind. This is true in spite of the fact that power and dominion ultimately fell to the lot of those races which originally dwelt in colder and more hilly or thickly-wooded regions, where the instincts of hunting and of warfare were naturally developed, so that, by degrees, the peoples who understood irrigation fell under the sway of those who neither needed nor appreciated it. In the long interval vast forests have been cleared away and the warlike habits of the northern and mountainous races have been greatly modified, but manufacturing progress among them has enabled them to perpetuate the power originally secured by the bow and the spear. The irrigating races of mankind are now held in fear of the modern weapons which are the products of the iron and steel industries, just as they were thousands of years ago terrorised by the inroads of the wild hunting men from the North.

But the future of agriculture will very largely belong to a class of men who will combine in themselves the best attributes of the irrigationist and the man who knows how to use the iron weapon and the iron implement. As the manufacturing supremacy of the North becomes more and more assured by reason of the superior healthiness of a climate encouraging activity of muscle and brain, so the agricultural prospects of the warmer regions of the earth's surface will be improved by the comparative immunity of plant and of animal life from disease in a dry atmosphere. Sheep, cattle and horses thrive far better in a climate having but a scanty rainfall than in one having an abundance of wet; and so, also, does the wheat plant when the limited rains happen to be timed to suit its growth, and the best kinds of fruit trees when the same conditions prevail.

All this points to an immense recrudescence of irrigation in the near future. Already the Californians and other Americans of the Pacific Slope have demonstrated that irrigation is a practice fully as well suited to the requirements of a thoroughly up-to-date people as it has been for long ages to those of the "unchanging East". But here again the question of cheap power obtrudes itself. The Chinese, Hindoos and Egyptians have long ago passed the stage at which the limited areas which were irrigable by gravitation, without advanced methods of engineering, have been occupied; and the lifting of water for the supplying of their paddy fields has been for thousands of years a laborious occupation for the poorest and most degraded of the rural population.

In a system of civilisation in which transport costs so little as it does in railway and steam-ship freights, the patches of territory which can be irrigated by water brought by gravitation from the hills or from the upper reaches of rivers are comparatively easy of access to a market. This fact retards the advent of the time when colossal installations for the throwing of water upon the land will be demanded. When that epoch arrives, as it assuredly will before the first half of the twentieth century has been nearly past, the pumping plants devoted to the purposes of irrigation will present as great a contrast to the lifting appliances of the East as does a fully loaded freight train or a mammoth steam cargo-slave to a coolie carrier.

At the same time there must inevitably be a great extension of the useful purposes to which small motors can be applied in irrigation. Year by year the importance of the sprinkler, not only for ornamental grounds such as lawns and flower-beds, but also for the vegetable patch and the fruit garden, becomes more apparent, and efforts are being made towards the enlargement of the arms of sprinkling contrivances to such an extent as to enable them to throw a fine shower of water over a very large area of ground. Sometimes a windmill is used for pumping river or well-water into high tanks from which it descends by gravitation into the sprinklers, the latter being operated by the power of the liquid as it descends. This mode of working is convenient in many cases; but a more important, because a more widely applicable, method in the future will be that in which the wind-motor not only lifts the water, but scatters it around in the same operation. Long helical-shaped screws, horizontally fixed between uprights or set on a swivel on a single high tower, can be used for loading the breeze with a finely divided shower of water and thus projecting the moisture to very long distances. A windmill of the ordinary pattern, as used for gardens, may be fitted with a long perforated pipe, supported by wire guys instead of a vane, a connection being made by a water-tight swivel-joint between this pipe and that which carries the liquid from the pump. In this way every stroke of the machine sends innumerable jets of water out upon the wind, to be carried far afield. Gardening properties in comparatively dry climates, fitted with machines of this description, can be laid out in different zones of cultivation, determined according to the prevailing directions of the wind and the consequent distribution of the water supply. Thus if the wind most frequently blows from the west the plants which require the most water must be laid out at the eastern side, not too far from the sprinkler. Facilities for shutting off the supply of spray at will are, of course, very necessary. The system of watering founded on this principle depends upon the assumption that if the gardener or the farmer could always turn on the rain when he has a fairly good wind he would never lack for seasonable moisture to nourish his crops. This will be found in practice to apply correctly to the great majority of food plants. In the dry climates, which are so eminently healthy for cereals, "the early and the latter rains," as referred to in Scripture, are both needed, and one of the most important applications of cheap power will be directed to supplementing the natural supply either at one end or at the other.

The "tree-doctor" will be a personage of increasing importance in the rural economy of the twentieth century. He is already well in sight; but for lack of capital and of a due appreciation of the value of his services, he occupies as yet but a comparatively subordinate position. Fruits, which are nature's most elaborately worked-up edible products, must come more and more into favour as the complement to the seed food represented by bread. As the demand increases it will be more clearly seen that an enormous waste of labour is involved in the culture of an orchard unless its trees are kept in perfect health. At the same time the law of specialization must operate to set aside the tree-doctor to his separate duties, just as the physician and the veterinary surgeon already find their own distinctive spheres of work. The apparatus required for the thorough eradication of disease in fruit trees will be too expensive for the average grower to find any advantage in buying it for use only a few times during the year; but the tree-doctor, with his gangs of men, will be able to keep his special appliances at work nearly all the year round.

For the destruction of almost all classes of fruit-pests, the only really complete method now in sight is the application of a poisonous gas, such as hydrocyanic acid, which is retained by means of a gas-proof tent pitched around each tree. No kind of a spray or wash can penetrate between bark and stem or into the cavities on fruit so well as a gaseous insecticide which permeates the whole of the air within the included space. But the gas-tight tent system of fumigation is as yet only in its infancy, and its growth and development will greatly help to place the fruit-growing industry on a new basis, and to bring the best kinds of fruit within the reach of the middle classes, the artisans, and ultimately even the very poor. Just as wheaten bread from being a luxury reserved for the rich has become the staple of food for all grades of society, so fruits which are now commonly regarded as an indulgence, although a very desirable addition to the food of the well-to-do, must, in a short time, become practically a necessity to the great mass of the people generally.

The waste of effort and of wealth involved in planting trees and assiduously cultivating the soil for the growth of poor crops decimated by disease is the prime cause of the dearness of fruit. If, therefore, it be true that the fruit diet is one which is destined to greatly improve the average health of civilised mankind, it is obvious that the tree-doctor will act indirectly as the physician for human ailments. When this fact has been fully realised the public estimation in which economic entomology and kindred sciences are held will rise very appreciably, and the capital invested in complete apparatus for fighting disease in tree life will be enormously increased.

Very long tents, capable of covering not merely one tree each, but of including continuous rows stretching perhaps from end to end of a large orchard, will become practically essential for up-to-date fruit-culture. An elongated tent of this description, covering a row of trees, may be filled with fumes from a position at the end of the row, where a generating plant on a trolley may be situated. At the opposite end another trolley is stationed, and each movable vehicle carries an upright mast or trestle for the support of the strong cable which passes along the row over the tops of the trees and is stretched taut by suitable contrivances. Attached to this cable is a flexible tube containing a number of apertures and connected at the generating station with the small furnace or fumigating box from which the poisonous gases emanate.

Along the ground at each side of the row are stretched two thinner wires or cables which hold the long tent securely in position. The method of shifting from one row to another is very simple. Both trolleys are moved into their new positions at the two ends of a fresh row, the fastenings of the tent at the ground on the further side having been released, so that the flap of the tent on that side is dragged over the tops of the trees and may then be drawn over the top cable and down upon the other side. Seen from the end, the movements of the tent thus resemble those of a double-hinged trestle in the form of an inverted V which advances by having one leg flung over the other. For this arrangement of a fumigating tent it is best that the top cable should consist of a double wire, the fabric of the tent itself being gripped between the two wires, and a flexible tube being attached to each.

As progress is made from one row to another through the drawing of one flap over the other, it is obvious that the tent turns inside out at each step, and if only one cable and one tube were used, it would be difficult to avoid permitting the gas to escape into the outer air at one stage or another. But when the tubes are duplicated in the manner described, there is always one which is actually within the tent no matter what position the latter may be in. It is then only necessary that the connection with the generating apparatus at the end of the row should be made after each movement with the tube which is inside the tent. For very long rows of trees the top cable needs to be supported by intermediate trestles besides the uprights at the ends.

The gas and air-proof tent can be used for various other purposes besides those of killing pests on fruit trees. One of the regular tasks of the tree-doctor will be connected with the artificial fertilisation of trees on the wholesale scale and for a purpose such as this it is necessary that the trees to be operated upon shall not be open to the outside atmosphere, but that the pollen dust, with which the air inside the tent is to be laden, shall be strictly confined during a stated period of time. Those methods of fertilisation, with which the flower-gardener has in recent years worked such wonders, can undoubtedly be utilised for many objects besides those of the variation of form and hue in ornamental plants.