Sulfur, chemical symbol S, has beeen known since antiquity, and its occurrence in the natural state in Sicily insured its availability to the early Mediterranean civilizations. Homer mentioned its medicinal properties about 900 BC, and the fumes of burning sulfur (sulfur dioxide, SO2) have long been used for bleaching textiles and for fumigation.

The name can be traced to the Sanskrit word sulveni which was the basis of the Roman word sulphurium. It is also known as brimstone from the German word Brennstein meaning burning stone. To the alchemist sulfur, along with mercury, was an essential ingredient of all metals, and it was not until the work of the French chemist Antoine Laurent Lavoisier in the late eighteenth century that it was classified as a chemical element.

Concentrated juice is then boiled to a supersaturated (highly concentrated) solution in vacuum pans. Crystallization is induced by seeding with a magnum of sugar and syrup to form a mixture of sugar crystals and liquor, known collectively as massecuite. The massecuite is discharged from the vacuum pans at 160° F (71° C) into water-cooled crystallizers where further sugar crystals are formed by reducing the temperature to about 100° F (37.8° C) over a 48-hour period. The raw sugar crystals are separated by reheating the massecuite to 122° F (50° C) to reduce the viscosity, followed by treatment in basket centrifuges operating at 1500 rpm. The residual syrup purged from the massecuite – a dark viscous liquid known as black-strap molasses – is used in the manufacture of rum, industrial alcohol and citric acid.

Sugar beet processing is a relatively simple process. The beets are washed and sliced up. Sucrose is extracted from the slices with hot water, and the solution obtained is purified by precipitating calcium carbonate in it. Impurities are trapped in the precipitate and filtered out. The process is repeated several times to give a clear solution. Vacuum evaporation is used to concentrate the solution – which is seeded and cooled so that the sugar crystallizes out.
Much of the world’s sugar cane is harvested by handcutting after burning the crop to remove the leaves. However, mechanical systems such as push-rake cutting and grab harvesting have come into use. The cane arriving at the raw sugar factory is washed on conveyers to remove field mud, sand and trash. The cane is nearly 90 per cent juice and it was traditionally extracted by a combination of shredders and three-roll crushers which squeezed out the juice.

Sugar cane existed in New Guinea 12,000 years ago and was cultivated in Egypt and the coastal lands of the Mediterranean about 3000 BC. A soft, sweet and thin-stemmed variety, known as Criolla, was introduced into the West Indies in 1493 by the explorer Christopher Columbus. During the eighteenth century, sugar cane plantations developed rapidly in the colonies of many European countries as a result of the cheap supply of slave labor drawn from the African continent. The modern varieties of sugar cane are hybrids of Saccharum officinarum, S. robustum and S. spontaneum, which have been bred to resist Mosaic disease and to give high yields.

Electric trains were first used in subways in 1890 (on the City and South London line in Britain), and all subsequent underground railways have been electrically worked. Subsurface cut-and-cover lines ‘everywhere are also electrically worked. The early locomotives used on underground railways have given way to multiple-unit trains, with separate motors at various points along the train driving the wheels, but controlled from a single driving cab. With most subway systems, steel wheels running on steel track are used, but some systems have been developed using pneumatic tires running on tracks. These are claimed to offer a smoother ride and give greater traction that allows more rapid acceleration and braking.

Two famous rivers rise in the mountains of Armenia — the Tigris and the Euphrates. Flowing  southward, they approach each other to form a common valley, proceed in parallel channels for the greater part of their course, and unite shortly before reaching the Persian Gulf. In antiquity each river had a separate mouth.

The soil which the Tigris and Euphrates bring down every year fills up the Persian Gulf at the rate of about three miles a century. Their delta was therefore much less extensive five or six thousand years ago than it is to-day.