and energy to bear on the solution of the problem. Water is procured in the district of Tehran by digging a series of deep pits, and establishing an underground communication from the higher to the lower. After a certain distance the water appears on the surface of the ground, and it runs in an open channel to its destination. These water-courses are called "kanats," and the whole plain of Tehran is covered with them. The earth taken up where the shafts are sunk forms little mounds at the mouths of the pits, and rows of these can be traced in all directions. Besides these artificial streams there are many small natural rivulets which continually flow down from the slopes of the Elburz mountains, but which of themselves would be far from sufficient for supplying the wants of a large city. At the distance of twenty-four miles to the west of Tehran the river of Kerij bursts through a mountain gorge into the plain, and a portion of its waters has been turned from its natural course and brought eastwards to the city by means of a canal. Where this canal joins the river a large body of water flows into it from the latter, but ere the water has traversed its course of four-and-twenty miles its bulk has diminished to one-seventh part of the original volume. The porous soil it runs over absorbs the remaining six parts, with the exception of what escapes by evaporation. A more energetic race to whom water was as precious as it is to the inhabitants of Tehran would long ere this
have constructed a covered water-tight aqueduct to replace the open canal, which would increase the supply of water sevenfold. There are other means which might be adapted for supplying the element that is wanted to turn so many square miles of desert into fertile fields
