Among the objects which attract attention, as one moves through the streets, are the public fountains scattered over the city. They are found everywhere, and are often remarkable for their architectural beauty. Their number is explained by the fact that the old system of water-supply did not bring water into the houses, but only to the different quarters of the city, thus making it necessary to have, at convenient points, outlets from which the inhabitants could obtain water, either by coming to draw it for themselves, or by engaging the services of water-carriers. However inconvenient this arrangement may seem, it was always a pleasing sight to see groups of women and children gathered towards evening about the fountain (Tchesmè) of their district to fill graceful, bright-coloured pitchers at the gushing faucets, and then to wend homewards. It took one far back in the ways of the world, and was a bit of the country in the town. Nor are the faithful water-carriers (sakka) forgotten, who brought water in great leathern vessels, shaped like a blunderbuss, hung horizontally by a strap from the left shoulder, and who poured the contents into a large earthenware vessel within your house. The aqueducts of Valens, Justinian, and other Byzantine Emperors, as well as the Basilica Cistern (Yeri Batan Serai) still act their part in furnishing the city with water. Until recently, the only other source of water-supply was either rain-water led from the roof into a cistern built under the house, or water brought in barrels from springs in the surrounding country. The introduction of water from the Lake of Derkos, which lies close to the Black Sea, to the west of the Bosporus, has been a great boon to the city, but it is not in favour for drinking purposes. [Illustration: A FOUNTAIN BY THE BOSPORUS In this form of fountain the tank is enclosed within four marble walls and roofed over.]