In Britain the growth of the textile industry brought a sudden increase of interest in the chemical industry, because one formidable bottleneck in the production of textiles was the long time that was taken by natural bleaching techniques, relying on sunlight, rain, sour milk, and urine. The modern chemical industry was virtually called into being in order to develop more rapid bleaching techniques for the British cotton industry. Its first success came in the middle of the 18th century, when John Roebuck invented the method of mass producing sulfuric acid in lead chambers. The acid was used directly in bleaching, but it was also used in the production of more effective chlorine bleaches, and in the manufacture of bleaching powder, a process perfected by Charles Tennant at his St. Rollox factory in Glasgow in 1799. This product effectively met the requirements of the cotton-textile industry, and thereafter the chemical industry turned its attention to the needs of other industries, and particularly to the increasing demand for alkali in soap, glass, and a range of other manufacturing processes. The result was the successful establishment of the Leblanc soda process, patented by Nicolas Leblanc in France in 1791, for manufacturing sodium carbonate (soda) on a large scale; this remained the main alkali process used in Britain until the end of the 19th century, even though the Belgian Solvay process, which was considerably more economical, was replacing it elsewhere.

Innovation in the chemical industry shifted, in the middle of the 19th century, from the heavy chemical processes to organic chemistry. The stimulus here was less a specific industrial demand than the pioneering work of a group of German scientists on the nature of coal and its derivatives. Following their work, W.H. Perkin, at the Royal College of Chemistry in London, produced the first artificial dye from aniline in 1856. In the same period, the middle third of the 19th century, work on the qualities of cellulosic materials was leading to the development of high explosives such as nitrocellulose, nitroglycerine, and dynamite, while experiments with the solidification and extrusion of cellulosic liquids were producing the first plastics, such as celluloid, and the first artificial fibres, so-called artificial silk, or rayon. By the end of the century all these processes had become the bases for large chemical industries.

An important by-product of the expanding chemical industry was the manufacture of a widening range of medicinal and pharmaceutical materials as medical knowledge increased and drugs began to play a constructive part in therapy. The period of the Industrial Revolution witnessed the first real progress in medical services since the ancient civilizations. Great advances in the sciences of anatomy and physiology had had remarkably little effect on medical practice. In 18th-century Britain, however, hospital provision increased in quantity although not invariably in quality, while a significant start was made in immunizing people against smallpox culminating in Edward Jenner’s vaccination process of 1796, by which protection from the disease was provided by administering a dose of the much less virulent but related disease of cowpox. But it took many decades of use and further smallpox epidemics to secure its widespread adoption and thus to make it effective in controlling the disease. By this time Louis Pasteur and others had established the bacteriological origin of many common diseases and thereby helped to promote movements for better public health and immunization against many virulent diseases such as typhoid fever and diphtheria. Parallel improvements in anesthetics (beginning with Sir Humphry Davy’s discovery of nitrous oxide, or “laughing gas,” in 1799) and antiseptics were making possible elaborate surgery, and by the end of the century X-rays and radiology were placing powerful new tools at the disposal of medical technology, while the use of synthetic drugs such as the barbiturates and aspirin (acetylsalicylic acid) had become established.

Agriculture

The agricultural improvements of the 18th century had been promoted by people whose industrial and commercial interests made them willing to experiment with new machines and processes to improve the productivity of their estates. Under the same sort of stimuli, agricultural improvement continued into the 19th century and was extended to food processing in Britain and elsewhere. The steam engine was not readily adapted for agricultural purposes, yet ways were found of harnessing it to threshing machines and even to plows by means of a cable between powerful traction engines pulling a plow across a field. In the United States mechanization of agriculture began later than in Britain, but because of the comparative labour shortage it proceeded more quickly and more thoroughly. The McCormick reaper and the combine harvester were both developed in the United States, as were barbed wire and the food-packing and canning industries, Chicago becoming the centre for these processes. The introduction of refrigeration techniques in the second half of the 19th century made it possible to convey meat from Australia and Argentina to European markets, and the same markets encouraged the growth of dairy farming and market gardening, with distant producers such as New Zealand able to send their butter in refrigerated ships to wherever in the world it could be sold.

Civil engineering

For large civil-engineering works, the heavy work of moving earth continued to depend throughout this period on human labour organized by building contractors. But the use of gunpowder, dynamite, and steam diggers helped to reduce this dependence toward the end of the 19th century, and the introduction of compressed air and hydraulic tools also contributed to the lightening of drudgery. The latter two inventions were important in other respects, such as in mining engineering and in the operation of lifts, lock gates, and cranes. The use of a tunneling shield, to allow a tunnel to be driven through soft or uncertain rock strata, was pioneered by the French émigré engineer Marc Brunel in the construction of the first tunnel underneath the Thames River in London (1825–42), and the technique was adopted elsewhere. The iron bell or caisson was introduced for working below water level in order to lay foundations for bridges or other structures, and bridge building made great advances with the perfecting of the suspension bridge—by the British engineers Thomas Telford and Isambard Kingdom Brunel and the German American engineer John Roebling—and the development of the truss bridge, first in timber, then in iron. Wrought iron gradually replaced cast iron as a bridge-building material, although several distinguished cast-iron bridges survive, such as that erected at Ironbridge in Shropshire between 1777 and 1779, which has been fittingly described as the “Stonehenge of the Industrial Revolution.” The sections were cast at the Coalbrookdale furnace nearby and assembled by mortising and wedging on the model of a timber construction, without the use of bolts or rivets. The design was quickly superseded in other cast-iron bridges, but the bridge still stands as the first important structural use of cast iron. Cast iron became very important in the framing of large buildings, the elegant Crystal Palace of 1851 being an outstanding example. This was designed by the ingenious gardener-turned-architect Sir Joseph Paxton on the model of a greenhouse that he had built on the Chatsworth estate of the duke of Devonshire. Its cast-iron beams were manufactured by three different firms and tested for size and strength on the site. By the end of the 19th century, however, steel was beginning to replace cast iron as well as wrought iron, and reinforced concrete was being introduced. In water-supply and sewage-disposal works, civil engineering achieved some monumental successes, especially in the design of dams, which improved considerably in the period, and in long-distance piping and pumping.

Transport and communications

Transport and communications provide an example of a revolution within the Industrial Revolution, so completely were the modes transformed in the period 1750–1900. The first improvements in Britain came in roads and canals in the second half of the 18th century. Although of great economic importance, these were not of much significance in the history of technology, as good roads and canals had existed in continental Europe for at least a century before their adoption in Britain. A network of hard-surfaced roads was built in France in the 17th and early 18th centuries and copied in Germany. Pierre Trésaguet of France improved road construction in the late 18th century by separating the hard-stone wearing surface from the rubble substrata and providing ample drainage. Nevertheless, by the beginning of the 19th century, British engineers were beginning to innovate in both road- and canal-building techniques, with J.L. McAdam’s inexpensive and long-wearing road surface of compacted stones and Thomas Telford’s well-engineered canals. The outstanding innovation in transport, however, was the application of steam power, which occurred in three forms.