‘The Oriental geography of Ebn Haukal, an Arabian traveller of the tenth century’ [‎264] (317/388)

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admit of the plying of boats ; but there are running streams, and
fountains, and meadows, and groves. The villages of the moun
tainous part of Setroushteh are these: Beshagher,
Ferghour, Baloam, Mesek, Lesken,
Besenk. These are situated on steep hills: and the cold part of
the country, also, has many strong fortresses. Here also ar^
mines of gold, and silver, and copperas, and sal ammoniac. The
mines of sal ammoniac Nushader) are in the mountains,
where there is a certain cavern, from which a vapour issues, ap
pearing by day like smoke, and by night like fire. Over the spot
whence the vapour issues, they have erected a house, the doors
and windows of which are kept so closely shut and plastered over
with clay that none of the vapour can escape. On the upper part
of this house the copperas rests. When the doors are to be
opened, a swiftly-running man is chosen, who, having his body
covered over with clay, opens the door; takes as much as he can of
the copperas, and runs off; if he should delay, he would be burnt.
This vapour comes forth in different places, from time to time;
when it ceases to issue from one place, they dig in another until
it appears, and then they erect that kind of house over it: if they
did not erect this house, the vapour would burn, or evaporate
away.
In the territory of ocJO^ Semendeh they make excellent iron.
Iron is also manutactured at Ferghaneh. At Semendeh