But their former tributaries no longer run their full course: the glacier-fed Zarafshan dries up amid the gardens of Bokhara soon after emerging from the highlands; and the Tejen and the Murghab lose themselves in the recesses of the Kara-kum desert.
It forms a dark-violet precipitate which dries to a greyish-violet powder.
Great care is necessary to prevent the heaps from becoming too hot, in which case the clay becomes baked into hard lumps of brick-like material which cannot be broken up. With careful management, however, the clay dries and bakes, becoming slowly converted into lumps which readily crumble into a fine powder, in which state it is spread over and worked into the land at the rate of 40 loads per acre.
The acacias and the Rosaceae yield their gums most abundantly when sickly and in an abnormal state, caused by a fulness of sap in the young tissues, whereby the new cells are softened and finally disorganized; the cavities thus formed fill with liquid, which exudes, dries and constitutes the gum.
The mushroom is a semi-deliquescent fungus which rapidly falls into putridity in decay, whilst the champignon dries up into a leathery substance in the sun, but speedily revives and takes its original form again after the first shower.