An Encyclopedia of the History of Technology part 81 docx

PART FIVE: TECHNOLOGY AND SOCIETY 782 In Europe the search for a harvesting machine was also being conducted in the early years of the nineteenth century, and the Society of Arts offered a prize for a number of years. Eventually the Revd Patrick Bell designed a machine, which was built by his local blacksmith and successfully used to harvest corn in the summer of 1828. Bell decided that his machine was so important that the restrictions in production that would occur if it was patented should be avoided. Unfortunately this meant that those imitations that were built were of poor and uncontrolled quality, and the idea lay dormant for a number of years owing to the bad reputation they gained. In the USA, Cyrus McCormick designed a reaper, which he patented in 1834 and put into limited production about the same time (Figure 16.2). While enjoying considerable success in America, it was some time before it was to appear in Europe. The incentive was the Great Exhibition held in London in 1851, and more particularly the trials organized that summer by the Royal Agricultural Society of England. Resistance to the machine was not pure conservatism, but also had a technical and economic basis. Not least of the problems was the ridge and furrow drainage system to be found on most of the heavy lands of Britain, which made it difficult, if not impossible, to operate the reaper. New drainage techniques being developed at about the same time were eventually to remove this particular obstacle, but the heavy investment needed created its own delay. Figure 16.2: The McCormick reaper, patented in 1834. This machine employed the essential features of the modern reaper: vibrating sickle-edged blade, fingers to hold the grain and reel, divider and platform to receive it. AGRICULTURE 783 These early reaping machines merely cut the corn and laid it on the ground for it to be tied into sheaves by hand, as had occurred with the sickle and scythe. Several manufacturers had managed to develop machines which would reap the corn, and also tie it into sheaves. The early machines used wire to bind the bundles, but in 1880 a farmer-inventor called Appleby produced the first successful twine binder, using a knotting mechanism that is still found on modern balers. Appleby’s invention rested on the accumulation of the previous experiences of a number of people, not least that of William Deering, who was the first to manufacture the machine. The cutting of corn now became a one-man operation, but the stocks had still to be stacked in the field to dry, and later to be carted to the barn for storage. During the winter months the grain had to be threshed from the straw, and then cleaned or winnowed to remove chaff, weed seeds and any other light material which might have become mixed up with it. Threshing and winnowing Because of the very weak stem that is a characteristic of the primitive cereals and the wild grass from which they derived, the seeds are easily dispersed. However the awns that surround the individual seed are very difficult to remove, and this would have presented problems to the early gatherers of the wild form, or cultivators of the primitive domestic varieties. As natural and human induced selection has caused the gradual evolution of these cereals, the features of most use to the farmer have been favoured. Thus the stem nodes have become stronger, allowing a considerable amount of rough treatment to the plant during the course of harvest, without consequent loss of seed. At the Figure 16.2: The McCormick reaper, patented in 1834. This machine employed the essential features of the modern reaper: vibrating sickle-edged blade, fingers to hold the grain and reel, divider and platform to receive it. PART FIVE: TECHNOLOGY AND SOCIETY 784 same time species have been developed in which the awns are more readily removed or, in some cases, completely absent. These benefits have been achieved at some cost, since the very high disease resistance of the primitive ancestors such as emmer has been lost, and the protein level of modern grain is also considerably lower. Threshing is the process whereby the individual seeds are separated from the stem of the plant, and also from the awns which surround them. Winnowing is carried out afterwards to produce a clean sample. Threshing requires a repeated and vigorous pounding of the corn so as to separate the various parts of the plant, but without damaging the seed itself. This can be accomplished by spreading the harvested crop on to a clean piece of ground and driving livestock over it so that their hooves crush the grain stems, or a device such as the norag or threshing sledge can be used. Alternatively, human effort can be utilized and the corn beaten with sticks. These may be just straight sticks, or may be specially developed flails which allow a greater force to be applied from a more upright stance. Either way the work is arduous and tedious. Wild cereal stands are still to be found in certain areas of the Middle East and Turkey, where they are occasionally harvested. This corn has firstly to be scorched or parched to make the awns more brittle and easily separated, and the same practice would have had to have been carried out by the prehistoric food processor. The changes that occurred as the early domestic species developed made this process unnecessary, but apart from this the methods employed for threshing the grain have remained remarkably similar throughout the world and over several millennia. Occasionally, and in certain parts of the world, reference may be found to some mechanical device to ease the process, but this has always been applied on the threshing floor. Where the climate will allow, this is situated in the open, but in northern Europe the slow winter threshing was conducted in an area specially set aside in the storage barn. The first practical threshing machine was invented in 1786 by the Scot Andrew Meikle (Figure 16.3). It consisted of a revolving drum along the edge of which were set four slats. The drum turned very close to a rounded mesh cage, the concave, whose curvature matched very closely the diameter of the drum. The combined effects of the slats and the pressure induced between the drum and concave, forced the seeds away from the other parts of the plant. The design of the Scottish machines required rollers to feed the corn gradually into the threshing chamber, with the result that the straw was severely damaged. In 1848, John Goucher in England patented the rasper bar cylinder which removed the need for these rollers, leaving the straw in a condition suitable for threshing, and also caused less damage to the seed. The peg tooth drum was invented in the USA in 1823. The principle employed was similar to the bars mounted on a drum, but teeth were also introduced to improve the threshing efficiency. The concept was very popular in America, and was used also in the newly developing combine harvesters (see pp. 785–6), but in AGRICULTURE 785 Europe, where a higher premium was placed on straw, the rasper bar predominated, and is still to be seen on modern conventional combine harvesters. By 1830 the threshing machine had been readily adopted into northern Britain, and was also making an appearance in the south. However the southern labourer depended on threshing during the winter months to provide work when it was impossible to get on to the land, and a series of riots resulted in the destruction of a large number of machines and a check in its rate of adoption. In the north the industrial manufacturing towns were able to offer higher wages than the farmer, and farm labour was more difficult to recruit. The machine therefore provided a much needed solution, as it did in other areas of the world where labour was always in short supply, such as America and Australia. By the 1850s resistance to the thresher had been overcome, and its overall adoption was speeded by the development of machines which could be driven by portable steam engines, allowing several farmers to share the capital investment. Combine harvesters The ideal harvest machine was of course one which was able to reap, thresh and clean the corn all in one operation, and this was achieved surprisingly quickly after the appearance of the first reaper. Hiram Moore’s earliest machine first ‘cut, threshed, separated, cleaned and sacked’ a field of wheat in Figure 16.3: Ground plan of Meikle’s thresher from Robert Forsyths ‘Principals and Practice of Agriculture,’ c. 1805. PART FIVE: TECHNOLOGY AND SOCIETY 786 1838 in Michigan, USA, but the success was not immediately followed through, partly because of wrangles over patent rights, and also because the machine only worked efficiently on crops that were ripe and dry. When a further example of Moore’s machine was tried out in California in 1854, it harvested 600 acres (243 hectares) of wheat in that one season. The 1838 machine cut a width of fifteen feet (4.6m) at each pass, and the developments that occurred in California followed this pattern. The farmer George Berry, in the Sacramento Valley, developed a machine with a forty foot (12.2m) cut, which was operated in the late 1880s, and about the same time another of his machines, powered by a straw burning steam engine, was the first self- propelled harvester to be produced. These, and later examples produced by manufacturers such as Best & Holt, could only have been developed for the great prairies of America, and apart from the much more compact Australian machine of the 1840s (see p. 781), there were no developments elsewhere until the early part of the twentieth century. By the late 1920s there were half a dozen American manufacturers producing machines capable of cutting between ten and eighteen feet (3–5.5m) of corn at one pass. The first of these crossed the Atlantic in 1927, being shown at the Empire Exhibition in London. The following year two machines were tried out in Britain, and trials were also conducted in continental Europe. Two European manufacturers recognized the potential, Clayton & Shuttleworth beginning production in Britain in 1929, with sales directed at the export market, and Claas in Germany testing a machine in 1931 which was aimed at domestic sales. Claas sold some 1400 of these machines over the next ten years, but generally acceptance in Europe was very slow. There were, for example, only 120 in Britain by the outbreak of the Second World War. The depressed state of European agriculture was part of the reason, but there was also a resistance from the corn merchants, suspicious of the quality of the corn that resulted from the drying process, which with the combine, became a necessary addition to the European harvest. In 1934 the Allis Chalmers company of America introduced their ‘All-Crop’ harvester. With a cutting width of five feet (1.5m), it would be pulled by a low powered tractor, was ideal for the small farmer, and most important of all, it cost less than a binder to buy. Within four years it dominated the US market and ensured that the binder was a machine of the past in that market, outstripping binder sales in the US by 1936. Since American manufacturers were so powerful in world markets, this ensured replacement of the binder in overseas markets as well. The war years had a profound effect on the spread of this machine, and of farm mechanization generally. On the Continent progress was virtually at a standstill. In Britain the massive ploughing-up campaign gave a stimulus to the spread of machinery in much the same way as it had during the First World War. But British manufacturers were geared to the production of tanks and other military equipment, and most of the machinery arriving on farms was therefore AGRICULTURE 787 from North America. In America itself, the demands for grain and other agricultural produce from Britain, Russia and China provided a stimulus for further mechanization, perhaps most graphically demonstrated by the ‘harvest brigade’ formed with the new self-propelled combines developed by Massey Harris. In 1944, 500 machines started harvesting in Texas in March, and completed over one million acres by September of that year. Since the war manufacturers have produced ever more sophisticated machines capable of handling larger acreages and heavier crops, but the general principle of the machine has remained the same. However, since the late 1970s many new designs have been tried in the attempt to accommodate the staggering increases in crop yield that have been achieved in the past fifteen years. FARM TRACTION The establishment of an economy based on plant domestication before one based on animals does not preclude the domestication and exploitation of a single species even earlier. French evidence suggests that horses may have been used from very early times, either as beasts of burden or for riding, on the basis of a characteristic form of dental wear noticed on a Palaeolithic horse jawbone. This raises the possibility that European hunter groups were aware of the potential of horse power well before any attempts were made at plant cultivation. This in itself was an important step, but much more significant was to be the utilization of this power for draught. Once again it is the Middle Eastern sculptures and frescos that provide the earliest evidence for the use of draught animals. A horse can carry only a limited load on its back, but when used in harness to pull a wagon it is capable of moving many times this weight. In the earliest representations it is the now extinct relative of the horse, the onager, that is most usually portrayed, and then always in association with the chariot rather than the more humble plough. As a power source for cultivation the ox predates the horse. The method of harnessing for the ox is by means of a yoke attached to the horns, and this place of attachment is still to be found in many parts of the world today. In Europe this practice gave way to a design of yoke which fitted across the withers of the animal. The horse’s place in the early history of traction has traditionally been limited to the chariot and subsequently as an animal of prestige or war rather than of labour. Various arguments have been presented to explain this, ranging from the economic ones that the horse was more expensive to keep, and realized no useful meat at the end of its working life, to the technical one that it was not until the invention of the horse collar that the horse’s greater speed and power could be utilized. The collar possibly originated in China, appearing in Europe by about 1000 AD. Mediaeval PART FIVE: TECHNOLOGY AND SOCIETY 788 manuscripts show the horse being used with the harrow, which could only operate effectively at the greater speed possible with this animal. It is also occasionally shown in harness with the ox, but hardly ever on its own. Pictorial and documentary sources both testify to European plough teams of eight oxen yoked to the plough in four pairs, and it has always been supposed that these great teams were necessary because of the poor design and heavy draught of the ploughs being used. More recent work would suggest that the large teams were more to ensure that each individual animal was lightly loaded, and could therefore work day in, day out, over a very extended period. It is likely that the horse was used more in agriculture than surviving records might imply, even in mediaeval times, but it was nevertheless a gradual process of replacement that led to the horse predominating in the extended European scene, and some areas hung on to the use of the ox until animal power was replaced by the tractor. In each part of the world a suitable animal was chosen from the native stock: the water buffalo has possibly the widest distribution after cattle and horses, but the yak, camel and llama were all chosen because of their suitability to their native environment. South and Central America is exceptional in that it is the only area in which city states were developed on the strength of an agricultural system that depended on human muscle alone. In this region animals were used as beasts of burden, but there is no evidence for their ever being used for traction. Animal traction in agriculture is generally associated with the direct traction of implements on the land, but the invention of effective gearing systems so important to early industrial development, also had its counterpart on the farm. Horse wheels had provided power for machinery at least since Roman times, and in association with water power they were an important means for driving the fixed equipment of the homestead, such as the corn mill. The development of the steam engine was to see the displacement of much of this equipment, but for many smaller farmers animal gears provided a cheap and reliable power source. Steam engines by their very construction were of great weight, and fear was expressed that such weights might cause damage to the structure of the land. The early pioneers of the internal combustion engine were hampered by the attitudes of the steam age as well as by the materials and manufacturing technologies available to them. The early machines, both European and North American, were therefore built on similar lines to the steam engines they were to replace, and frequently weighed in excess of four tonnes. It is therefore not surprising that it was in the drier prairies of North America, in which there was the need to cultivate huge areas with limited man and horse power, that the agricultural motor was to be most readily applied. In Great Britain the pattern of development was being repeated, but one individual in particular recognized the need for a more compact power source. Dan Albone, a bicycle maker in Bedfordshire, produced his first machine in AGRICULTURE 789 1902. This motor weighed only 1 1/2 tonnes, and yet was capable of pulling a two-furrow plough, and later models were capable of three furrows, or of pulling two binders in tandem. Almost immediately Albone’s Ivel tractor (Figure 16.4) was being exported to countries on every continent. Albone himself died in 1906 and without his guidance the company produced no new ideas of significance; the initiative passed back to the Americans, or to those companies which were designing and producing for the American market. Up to the First World War the tractors being produced continued to be of the size determined by their ancestry. A very large number of companies were engaged in establishing a position in the market-place, but it was the Ford company that was to have the greatest impact on future developments. Henry Ford brought to the problem two important contributions. The first was technical, in that his tractor was built without a chassis, but with the engine, gearbox and transmission casings forming the structural strength. The idea was not new, having first appeared on the Wallis Cub in 1913. However, when Ford’s mass production manufacturing techniques were applied to the concept, he was able to market a machine which was not only much lighter than its rivals, but also significantly cheaper. As Ford was perfecting his new Fordson tractor, the British government was implementing a huge ploughing-up campaign to produce the corn necessary to replace that which was being denied to Britain by the successes of the German U-boat blockade. They therefore agreed to purchase the first 6000 Fordsons. Figure 16.4: Ivel tractor pulling two mowers, c. 1905. PART FIVE: TECHNOLOGY AND SOCIETY 790 The basic structural design of this machine is to be found on modern examples. To it have gradually been added a series of new features and also some which had been invented much earlier, but had never been followed up. For example, the idea of the power-take-off shaft, which had first appeared on the British Scott tractor in 1904 and on the French Gougis tractor in 1906, was reintroduced by the International Harvester company as an optional extra on their model 8–16 Junior in 1917, and as standard equipment on their 15–30 tractor which appeared in 1921. The power-take-off shaft allowed the power of the tractor’s engine to be transferred to the machine it was towing. Previous to this the moving parts of a machine such as a binder were driven via gearing from its ground wheels. This system was inefficient because of the slip of these wheels as they rolled on the ground, but it also meant that when a blockage occurred the machine had to be stopped, and the power that might have cleared the blockage was therefore not being provided. With the power-take- off, when the tractor was stopped, the tractor’s engine power could still be used to drive the equipment concerned. Most early tractors were merely used as horse replacements to provide the power to drag a particular implement through or across the ground. However as early as 1917 the Emerson-Brantingham tractor had a mechanical lift feature which allowed the direct mounting of specially designed implements. The idea reappeared in 1929 on the John Deere GP tractor in a mechanical form, and on the John Deere model ‘A’ in hydraulic form in 1934. At the same time Harry Ferguson in England was developing a hydraulic system which has become a standard feature on modern tractors. Ferguson’s system consisted of three arms to support the rear-mounted implement, the bottom two of which were raised or lowered by hydraulic pumps, and the top one was connected to valves which controlled the flow of oil to and from these pumps. Equipped with this system the implement could be carried by the tractor, greatly increasing its manoeuvrability compared to the trailed arrangement of its predecessors. Additionally the top link on the tractor could be set up in such a way that changes in soil depth or hardness would act on the hydraulic valves so that the depth of the implement would alter and compensate for the changes acting on it. Tractor hydraulics have now become extremely sophisticated, and are used to make running adjustments on both the tractor itself and the machinery it is towing. Additionally hydraulic pumps are used on equipment such as combine harvesters as a substitute for transmissions. The advantage of the system is that, unlike a gearbox, where the range of power selection choices is determined by the number of gears, the hydraulics system offers a limitless range of speed. Pneumatic tyres were issued as standard equipment on the 1935 Allis Chalmers Model ‘U’, and quickly became a standard fitting on most makes of tractor in America; their introduction into Europe was delayed by the shortage of rubber during the war. Pneumatic tyres greatly increased the grip of the AGRICULTURE 791 tractors’ wheels on the soil, allowed greater speeds of operation to be achieved with more efficient fuel consumption, and also allowed the tractor to be taken on to the public highway without the time-consuming need to protect the road from damage by the iron wheels. Their introduction did much to check the development of tracked crawler tractors, which had appeared very early on the scene in response to concern about soil damage. Modern low pressure tyres aim to compensate for the ever increasing size of modern machinery. This trend itself is in part to maximize capital investment in plant, but it is also an attempt to reduce the number of passes across a field that are needed to carry out all the year’s processes. The larger the tractor, the larger the implement it can carry or pull, and the greater the acreage covered in one trip down the field. There is a limit to this concept, and while it might have a validity in many areas of the world, the heavy reliance on petrochemical inputs makes it unsuitable in others. Animal or human power will always be a vital input into an agricultural system existing in a situation where the cost or supply of fuel outstrips the resources available. Indeed, many traditional systems maximize available resources in a way that is inconceivable within Western technology. The Indian sacred cow scavenges for its feed at little cost to the community in which it lives, and yet it provides that community with the calves which will grow into the draught oxen vital to its existence. DAIRY FARMING In terms of returns gained from a given level of input, milking whether of cow, sheep, goat or horse, is many times more efficient than the production of meat. As a form of subsistence economy it has the added benefit that in really hard times the slaughter of a percentage of the herd can provide a satisfactory safety net. If it is not carried to extremes, the herd can be brought back to a previous population level reasonably quickly after the return of the good times. The earliest evidence for milking comes from a fresco from Ubaid in Iraq, dated to 2500 BC. Later representations from the same area, and also from Egypt, suggest that milk from sheep and goats was also used. Curiously shaped pottery sherds discovered at Ghassul in the Jordan valley, in levels dated to the middle of the fourth millennium, have been identified as butter churns on the basis of their resemblance to the churns still used today by Arab nomads. This early processing of milk is important, since it demonstrates the ability to convert a highly perishable commodity into one which has some storage potential. Any society which changes its economy from one based on gathering and hunting, and which may therefore store little beyond its most immediate needs, will very quickly be faced with the need to store the products of a bountiful season in order to see it through less favourable times. . the slats and the pressure induced between the drum and concave, forced the seeds away from the other parts of the plant. The design of the Scottish machines required rollers to feed the corn. The depressed state of European agriculture was part of the reason, but there was also a resistance from the corn merchants, suspicious of the quality of the corn that resulted from the drying process,. the chariot rather than the more humble plough. As a power source for cultivation the ox predates the horse. The method of harnessing for the ox is by means of a yoke attached to the horns, and