Its basin forms the province of Kabul, which includes all northern Afghanistan between the Hindu Kush and the Safed Koh ranges.
Half a mile east of Kabul it is joined by the Logar, a much larger river, which rises beyond Ghazni among the slopes of the Gul Koh (14,200 ft.), and drains the rich and picturesque valleys of LGgar and Wardak.
It rises in the northern slopes of the Koh-i-Baba to the west of Kabul, and finally loses itself in the Tejend oasis north of the Trans-Caspian railway and west of Merv.
It rises in the southern slopes of Siah-Koh, which forms the southern wall of the valley of Herat, and after a south-westerly course of about 200 m.
On the west, Badakshan is bounded by a line which crosses the Turkestan plains southwards from the junction of the Kunduz and Oxus rivers till it touches the eastern waterdivide of the Tashkurghan river (here called the Koh-i-Chungar), and then runs south-east, crossing the Sarkhab affluent of the Khanabad (Kunduz), till it strikes the Hindu Kush.
Of its length, from its roots in the Pamir regions till it fades into the Koh-i-Baba to the west of Kabul, this great range forms the water-divide between the Kabul and the Oxus basins, and, for the first 200 m.
Those utilized were the Kaoshan (the "Hindu Kush" pass par excellence), 14,340 ft.; the Chahardar (13,900 ft.), which is a link in one of the amir of Afghanistan's high roads to Turkestan; and the Shibar (9800 ft.), which is merely a diversion into the upper Ghorband of that group of passes between Bamian and the Kabul plains which are represented by the Irak, Hajigak, Unai, &c. About this point it is geographically correct to place the southern extremity of the Hindu Kush, for here commences the Koh-i-Baba system into which the Hindu Kush is merged.
Probably, however, the title was confined to the section from Khawak to Koh-i-Baba.
The name has by some later Oriental writers been modified into Hindu Koh (mountain), but this is factitious, and throws no more light on the origin of the title.
Reaches to the foot of the Koh-i-Mulla Khwaja, crossing the Jui Nao or " new " canal, which here divides the gravelcovered foot hills from the alluvial flats of the Hari Rud plain.
Farther the road winds first amongst the broken ridges of the Koh-i-Mulla Khwaja, then over the intervening dasht into the southern spurs of the Paropamisus to the Ardewan pass.
The long narrow valley of the Hari Rud, starting from the western slopes of the Koh-i-Baba, extends almost due west for 300 m.
For the greater part of its length it drains the southern slopes only of the Paropamisus and the northern slopes of a parallel range called Koh-i-Safed.
From its source; and it is this tributary (separated from the Hari Rud by the narrow ridges of the Koh-i-Safed and Band-iBaian) that offers the high road from Herat to Kabul, and not the Hari Rud itself.
Due north the hills called the Koh-i-Mulla Khwaja appear to be close and dominating, but the foot of these hills is really about 3 m.
To the north-east of the city a very considerable valley has been formed between the Paropamisus and the subsidiary Koh-i-Mulla Khwaja range, called Korokh.
Potassium hydroxide or caustic potash, KOH, formerly considered to be an oxide but shown subsequently to be a hydroxide of potassium, may be obtained by dissolving the metal or monoxide in water, but is manufactured by double decomposition from potassium carbonate and slaked lime: K 2 CO 3 -E-Ca(OH) 2 =2KOH+CaC03.
On crystallizing a solution, the hydrate KOH 2H 2 0 is deposited; 2KOH 9H 2 0 and 2KOH 5H 2 0 have also been obtained.
The boundary of the province here follows the line of the Safed Koh, which overlooks the Afridi Tirah and the upper Kurram valley.
The range of the Safed Koh flanks the Kurram valley and encloses the Kabul basin, which finds its outlet to the Indus through the Mohmand hills.
To the east the Safed Koh extends its spurs into the Kohat district.
The chief peaks in the province are Kaisargarh (11,300 ft.) and Pir Ghol (11,580 ft.) in Waziristan; Shekh Budin (4516 ft.), in the small range; Sikaram (15,621 ft.) in the Safed Koh; Istragh (18,900 ft.), Kachin (22,641 ft.) and Tirach Mir (25,426 ft.), in the Hindu Kush on the northern border of the Chitral agency; while the Kagan peaks in Hazara district run from 10,000 ft.
The Kurram river rises in the southern slopes of the Safed Koh, and after leaving the Kurram valley passes through the Kohat hills and enters Bannu district.
SAFED KOH (" white mountain"), in many respects the most remarkable range of mountains on the north-west frontier of Pakistan, extending like a 14,000 ft.
Geographically the Safed Koh is not an isolated range, for there is no break in the continuity of water divide which connects it with the great Shandur offshoot of the Hindu Kush except the narrow trough of the Kabul river, which cuts a deep waterway across where it makes its way from Dakka into the Peshawar plains.
Approaching the Peshawar plains the Safed Koh throws off long spurs eastward, and amongst the foothills of these eastern spurs the Afridi Tirah long remained hidden from European eyes.
The Koh and Ramganga are the principal rivers that flow through the district, and the Ganges forms its western boundary.
The Koh-i-nor, which was in 1739 in the possession of Nadir Shah, the Persian conqueror, and in 1813 in that of the raja of Lahore, passed into the hands of the East India Company and was by them presented to Queen Victoria in 1850.
The Koh-i-nor has been identified by some authors with this stone and by others with the stone seen by Tavernier.
Tavernier, however, subsequently described and sketched the diamond which he saw as shaped like a bisected egg, quite different therefore from the Koh-i-nor.
Being possessed of the Koh-i-noor diamond, and being fortunate enough to intercept a consignment of treasure on its way to the shah of Persia, he had all the advantages which great wealth can give.
In 1833 when Shah Shuja, flying from Afghanistan, sought refuge at his court, he took from him the Koh-i-nor diamond, which subsequently came into the possession of the British crown.
The alkaline liquid is now transferred to vacuum pans, constructed in such a manner that the unchanged chloride, which " salts out " during the concentration, can be removed without disturbing the vacuum, and here at last a concentrated pure solution of KOH or NaOH is obtained which is sold in this state, or " finished " as solid caustic in the manner described in the section treating of the Leblanc soda.
Its remains lie in a valley of the Hazara country, on the chief road from Kabul towards Turkestan, and immediately at the northern foot of that prolongation of the Indian Caucasus now called Koh-i-Baba.
From the neighbourhood of Landi Kotal the boundary is carried to the Safed Koh overlooking the Afridi Tirah, and then, rounding off the cultivated portions of the Kurram valley below the Peiwar, it crosses the Kaitu and passes to the upper reaches of the Tochi.
From Nushki it crosses the Helmund desert, touching the crest of a well-defined mountain watershed for a great part of the way, and, leaving Chagai to Baluchistan, it strikes nearly west to the Persian frontier, and joins it on the Koh-i-Malik Siah mountain, south of Seistan.
Goldsmid's Commission in 1872 from the Malik-Siah-Koh to the Helmund Lagoons, and rectified by the Commission under Sir Henry MacMahon in 1903-1905.
The dominant mountain system of Afghanistan is the Hindu Kush, and that extension westwards of its water-divide which is indicated by the Koh-i-Baba to the north-west of Kabul, and by the Firozkhoi plateau (Karjistan), which merges still farther to the west by gentle gradients into the Paropamisus, and which may be traced across the Hari Rud to Mashad.
The culminating peaks of the Koh-i-Baba overlooking the sources of the Hari Rud, the Helmund, the Kunduz and the Kabul very nearly reach 17,000 ft.
The Band-i-Turkestan anticlinal may be traced eastwards of the Balkh-ab (the Band-i-Amir) within the folds of the Kara Koh to the Kunduz, and beyond; but the Kara Koh does not mark the northern wall of the great plateau nor overlook the sands of the Oxus plain, as does the Band-i-Turkestan.
On the south this great band of roughly undulating central plateau is bounded by the Koh-i-Baba, to the west of Kabul, and by the Hindu Kush to the north and north-east of that city.
After the Hindu Kush and the Turkestan mountains, that range which divides Ningrahar (or the valley of Jalalabad) from Kurram and the Afridi Tirah, and is called Safed Koh (also the name of the range south of the Hari Rud), is the most important, as it is the most impressive, in Afghanistan.
The highest peak of the Safed Koh, Sikaram, is 15,600 ft.
Kabul is linked with Afghan Turkestan and Badakshan by three main lines of communication across the Koh-i-Baba and the Hindu Kush.
From Bamian it passes over the central mountain chain to Kabul either by the well-known passes of Irak (marking the water-divide of the Koh-i-Baba) and of Unai (marking the summit of the Sanglakh, a branch of the Hindu Kush), or else, turning eastwards, it crosses into the Ghorband valley by the Shibar, a pass which is considerably lower than the Irak and is very seldom snowbound.
Respectively) across the southern extensions of the Safed Koh range, and has never been a great trade route, however suitable as an alternative military line of advance.
Between Kabul and Herat there is no " royal " road, the existing route passing over the frequently snowbound wastes that lie below the southern flank of the great Koh-iBaba into the upper valleys of the Hari Rud tributaries.
The universal custom of sleeping on the house-top in summer promotes rheumatic and neuralgic affections; and in the Koh Daman of Kabul, which the natives regard as having the finest of climates, the mortality from fever and bowel complaint, between July and October, is great, the immoderate use of fruit predisposing to such ailments.
Lead is found in Upper Bangash (Kurram district), and in the Shinwari country (also among the branches of Safed Koh), and in the Kakar country.
In the Koh-Daman, north of Kabul, are the sites of several ancient cities, the greatest of which, called Beghram, has furnished coins in scores of thousands, and has been supposed to represent Alexander's Nicaea.