French chalk is a variety of granular talc. It is used for drawing lines on cloth and is used by athletes and gymnasts to put on their hands to stop them slipping. In painting and decorating, French chalk is sometimes incorporated into paint as an extender to help keep the pigments in suspension. Research French Chalk
Granite is a plutonic, igneous, crystalline, granular rock, consisting generally of quartz, feldspar, and mica, mixed up without regular arrangement of the crystals, and usually of a whitish, greyish, or flesh-red colour. The grains vary in size from that of a pin's head to a mass of almost one meter, but they seldom exceed about two centimetres. When they are of this size, or larger, the granite is said to be 'coarse-grained.'.
Granite is one of the most abundant of the igneous rocks seen at or near the surface of the earth, and was formerly considered as the foundation rock of the globe, or that upon which all sedimentary rocks repose; but it is now known to belong to various ages from the Pre-Cambrian to the Tertiary, the Alps of Europe containing granite of the later age. In Alpine situations it presents the appearance of having broken through the more superficial strata; the beds of other rocks in the vicinity rising towards it at increasing angles of elevation as they approach it. It forms some of the most lofty of the mountain chains of the eastern continent, and the central parts of the principal mountain ranges of Scandinavia, the Alps, the Pyrenees, and the CarpathianMountains are of this rock.
Granite supplies one of the most durable materials for building, as many of the ancient Egyptian monuments testify. It varies much in hardness as well as in colour, in accordance with the nature and proportion of its constituent parts, so that there is much room for care and taste in its selection. Granite in which feldspar predominates is not well adapted for buildings, as it cracks and crumbles down in a few years. The Aberdeen bluish-gray granite is celebrated for its great durability, and also for its beauty. The Peterhead red granite, the hue of which is due to its feldspar being the flesh-coloured potash variety called orthoclase, is highly esteemed for polished work, as columns, pillars, graveyard monuments, etc. Granite in which mica is replaced by hornblende is called syenite; when both mica, and hornblende are present it is called syenitic granite; when talc supplants mica it is called protogene, talcose, or chloritic granite; a mixture of quartz and hypersthene, with scattered flakes of mica, is called hypersthenic granite; and the name of graphic granite, or pegmatite, is given to a variety composed of feldspar and quartz, with a little white mica, so arranged as to produce an irregular laminar structure. When a section of this latter mineral is made at right angles to the alternations of the constituent materials, broken lines resembling Hebrew characters present themselves; hence the name.
Granite abounds in crystallized earthy minerals; and these occur for the most part in veins traversing the mass of the rock. Of these minerals beryl, garnet, and tourmaline are the most abundant. It is not rich in metallic ores. The orientalbasalt, found in rolled masses in the deserts of Egypt, and of which the Egyptians made their statues, is a true granite, its black colour being caused by the presence of hornblende and the black shade of the mica. The oriental red granite chiefly found in Egypt, and of which Pompey's Pillar and Cleopatra's Needles were constructed, is composed of large grains or imperfectly formed crystals of flesh-coloured feldspar, of transparentquartz, and of black hornblende. Research Granite
Hardness refers to the resistance of a smooth surface of a rock or mineral to scratching. It is determined by the binding force of atoms within the crystal structure and is measured according to Moh's ten division scale of hardness, ranging from 1 the softest, to 10 the hardest: 1) talc 2) gypsum 3) calcite 4) fluorite 5) apatite 6) orthoclase 7) quartz 8) topaz 9) corundum 10) diamond.
Materials, according to this arrangement, which are scratched by quartz and are not scratched by felspar are said to have a hardness between 6 and 7.
Potstone (Lapis ollaris) is a species of talc containing an admixture of chlorite. It is green in colour and varies in shade, greasy and soft but hardens on exposure to the air. It's English name comes from its capability to be turned into vases and pots by turning. Research Potstone
Pyrophyllite is a comparatively rare mineral found in metamorphic rocks and often with kyanite. It is a hydrous silicate of aluminium with the formulae A12Si4O10(OH)2 and a relative hardness of 2. It appears very similar to talc. Pyrophyllite is used industrially as a refractory mineral, as a filler for rubber, in paints and in insecticides. Research Pyrophyllite
Steatite (soapstone) is a variety of talc, hydrated magnesic silicate, usually devoid of a distinct crystalline structure. It is white, blue-grey, green or brown in colour, soft and easy to cut and heat-resisting. Since the earliest of times steatite has been used for ornaments and carvings. In a powdered form it is an ingredient in soaps, paints, lubricants and French chalk. Research Steatite
Talc has the formulae Mg3Si4O10(OH)2 and a relative hardness of 1. It is a mineral of secondary origin formed by the alteration of magnesiumsilicates. Usually found in metamorphic rocks where, in a non-crystalline form, it occurs as 'soapstone' - and can make up large rock masses. Used for laboratory table tops and for many industrial uses. It has a greasy feel. Research Talc
Afghanistan is a country in Asia. It has a total area of 647,500 km2 and a land area of 647,500 km2. The climate is extremely cold in the higher, and intensely hot in the lower regions, yet on the whole it is salubrious. The most common trees are pines, oaks, birch, and walnut. In the valleys fruits, in the greatest variety and abundance, grow wild. The principal crops are wheat, forming the traditional staple food of the people; barley,rice, and maize. Other traditional crops were tobacco, sugar-cane, and cotton, though since the 20th century opium has become a major crop.
Afghanistan consists chiefly of lofty, bare, uninhabited table-lands, sandy barren plains, ranges of snow-covered mountains, offsets of the Hindu Kush or the Himalayas, and deep ravines and valleys. Many of the last are well watered and very fertile, but about four-fifths of the whole surface is rocky, mountainous, and unproductive. The surface on the north-east is covered with lofty ranges belonging to the Hindu Kush, whose heights are often 18,000 and sometimes reach perhaps 25,000 feet. The whole north-eastern portion of the country has a general elevation of over 6000 feet; but towards the south-west, in which direction the principal mountain chains of the interior run, the general elevation declines to not more than 1600 feet. In the interior the mountains sometimes reach the height of 15,000 ft. G-reat part of the frontier towards India consists of the Suleiman range, 12,000 feet high. There are numerous practicable avenues of communication between Afghanistan and India, among the most extensively used being the famous Khyber Pass, by which the river Cabul enters the Punjab; the Gomul Pass, also leading to the Punjab; and the Bolan Pass on the south, through which the route passes to Sind.
Natural resources include opium, natural gas, crude oil, coal, copper, talc, barites, sulphur, lead, zinc, iron ore, salt, precious and semi-precious stones. The inhabitants belong to different races, but the Afghans proper form the great mass of the people. They are allied in blood to the Persians, and are divided into a number of tribes, among which the Duranis and Ghiljis are the most important. The Afghans are bold, hardy, and warlike, fond of freedom and resolute in maintaining it, but of a restless, turbulenttemper, and much given to plunder. Tribal dissensions have constantly been in existence, and seldom or never do all the Afghans pay allegiance to the nominal ruler of their country .The religion is 74% SunniMuslim, 15% Shia Muslim and 11% other. The official language is Pashto spoken by half the population, with 35% speaking Afghan Persian (Dari), 11% Turkic languages (primarily Uzbek and Turkmen), 4% thirty minor languages (primarily Balochi and Pashai) with widespread bilingualism.
In 1738 the country was conquered by the Persians under Nadir Shah. On his death in 1747 Ahmed Shah, one of his generals, obtained the sovereignty ofAfghanistan, and became the founder of a dynasty, which lasted. about eighty years. At the end of that time Dost Mohammed, the ruler of Kabul, had acquired a preponderating influence in the country. On account of his dealings with the Russians the British resolved to dethrone him and restore Shah Shuja, a former ruler.
In April, 1839, a British army under Sir John Keane entered Afghanistan, occupied Kabul, and placed Shah Shuja on the throne, a force of 8000 being left to support the new sovereign. Sir W Macnaghten remained as envoy at Kabul, with Sir Alexander Burnes as assistant envoy. The Afghans soon organized a widespread insurrection, which came to a head on November the 2nd,1841, when Burnes and a number of British officers, besides women and children, were murdered, Macnaghten being murdered not long after. The other British leaders now made a treaty with the Afghans, at whose head was Akbar, son of Dost Mohammed, agreeing to withdraw the forces from the country, while the Afghans were to furnish them with provisions and escort them on their way.
On the 6th of January, 1842 the British left Kabul and began their most disastrous retreat. The cold was intense, they had almost no food - for the treacherous Afghans did not fulfil their promises - and day after day they were assailed by bodies of the enemy. By the 13th of January 26,000 persons, including camp-followers, women and children, were killed. Some were kept as prisoners, but only one man, Dr. Brydon, reached Jelalabad, which, as well as Kandahar, was still held by British troops. In a few months General Pollock, with a fresh army from India, retook Kabul and soon finished the war.
Shah Shuja having been assassinated, Dost Mohammed again obtained the throne of Kabul, and acquired extensive power in Afghanistan. He joined with the Sikhs against the British, but latterly made an offensive and defensive alliance with the latter. He died in 1863, having nominated his son Shere Ali his successor. Shere Ali entered into friendly relations with the British, but in 1878, having repulsed a British envoy and refused to receive a British mission (a Russian mission being meantime at his court), war was declared against him, and the British troops entered Afghanistan. They met with comparatively little resistance ; the ameer fled to Turkestan, where he soon after died; and his son Yakoob Khan having succeeded him concluded a treaty with the British at Gandamak in May, 1879, in which a certain extension of the British frontier, the control by Britain of the foreign policy of Afghanistan, and the residence of a British envoy in Kabul, were the chief stipulations. Not long after this settlement the British resident at Kabul, Sir Louis P. Gavagnari, and the other members of the mission were treacherously attacked and slain by the Afghans, and troops had again to be sent into the country. Kabul was again occupied, and Kandahar and Ghazni were also relieved; while Yakoob Khan was sent to imprisonment in India.
In 1880 Abdur-Rahman, a grandson of Dost Mohammed, was recognized by Britain as ameer of the country. He was on friendly terms with the British during his reign, which ended with his death in 1901, his son Habibullah being his successor. Encroachments by the Russians on territory claimed by Afghanistan almost brought about a rupture between Britain and Russia in 1885, and led to the delimitation of the frontier of Afghanistan on the side next Russia,
In 1926 a royal kingdom was established in Afghanistan, this was overthrown in 1973 and a republic was declared. There followed a period of unrest until in 1979 a left-wing coup occurred. Civil war ensued and the Soviet Union invaded at the invitation of the government. The American government and its allies sponsored and armed a Islamic fundamentalist
opposition - the Mujaheddin - and in 1989 the Soviets withdrew and in in 1992 the Mujaheddin gained power, installing a very fundamentalist Islamic government known as the Taliban. The Taliban were then overthrown by an American-led invasion in 2002 following the Taliban's support for those responsible for the attack on the World Trade Center in New York and a coalition of tribal warlords was put in power. Since then civil unrest has once again continued, as it always has in Afghanistan. Research Afghanistan
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Cipolin
