were about two hundred feet apart. These pits were convenient for giving air and light beneath, and also afforded a ready means of getting rid of the excavated earth and rocks. It is possible, that at the period when these tunnels were made, the pits were previously dug, in order to enable them to give the necessary direction and level to the subterranean passage. Branches from this main stream are continually thrown off to supply the villages, and the palaces of the sultan along the Bosphorus. Notwithstanding all these expensive works, it some- times happens, after long droughts, that the supply becomes scanty in the suburbs ; and during my residence here, I have known water to be sold at Pera and Galata at from two to six cents a pail-ful. This, however, never occurs in the city itself, which is abundantly supplied at all seasons of the year. " Where a valley of great extent is to be crossed, the Turks have resorted to an ingenious contrivance, which I have nowhere seen clearly described, but which, from its simplicity and value, merits a more particular notice. From the want of sufficient mechanical skill to manufacture water-pipes strong enough to bear the weight of a large column of water, they adopted the following plan : in the direction of the proposed water-channel, a number of square pillars are erected at certain short intervals ; they are about five feet square, constructed of stone, and, slightly resembling pyramids, taper to the summit. They vary in height, according to the necessities of the case, from ten to fifty feet, and in some instances are even higher. " They form a striking peculiarity in Turkish scenery, and it was some time before the principle upon which they were constructed was apparent. The water leaves the brow of a hill, and descending in earthen pipes rises in leaden or earthen ones, up one side of this pillar, to its former level, which must be, of course, the summit of the pillar, or sooteray, as it called by the Turks.* The water is here discharged into a stone basin as large as the top of the sooteray, and is discharged by another pipe, which descends along the opposite side of the pillar, enters the ground, advances to the next sooteray, which it ascends and descends in the same manner ; and in this way the level of the water * This word is from the Turkish sooteraysoo, which means the levelling of the water, and expresses very well the object of the sooteray. 44 PRELIMINARY ESSAY. may be preserved for many miles over large ravines or plains, where an aqueduct would be, from its expensiveness, manifestly out of the question. In the city of Constantinople, the old ruinous aqueduct of Valens, which no longer conducts water in the usual manner, is converted into a series of sooterays, and permits one to examine their structure in detail. The stone basin on the summit is covered with an iron plate, to prevent the birds from injuring the water. This is connected by a hinge, and, upon lifting it up, the basin is found to be divided into two parts by a stone partition. Several holes are made in this partition near its upper edge. The water from the ascending pipe is allowed by this means to settle its foreign impurities, and the surface water, which is of course the most pure, flows through these apertures into the adjoining compartment, from whence it descends, and is carried to the next sooteray, where the same process is repeated. A number of projecting stones on the sides facilitate the ascent of the person who has charge of these sooterays, and whose business it is to remove the deposites from the water in the stone basins. " This ingenious hydraulic arrangement seems to possess advantages which might recommend its adoption elsewhere. As the pressure is thus divided among this series of syphons, the necessity for having very strong and costly pipes is obviated. As they are from three to five hundred yards apart, the cost is probably much less than by any plan which could be devised, where, in addition to the cost of a canal or series of pipes, we should be compelled to raise it again, by the expensive agency of steam or some other costly apparatus. The frequent exposure of the water to air and light at the summit of these sooterays, is another very important advantage which cannot be too strongly insisted upon ; as it is now well known that nothing tends more to purify water, than the presence of these two agents. The arrangement, likewise, of the basins on the top of the pillars, is well adapted for getting rid of much of the matters