There is always plenty of ice to be had during the summer here--perhaps not always of the cleanest, but still good enough for the purpose of cooling fruits and drinks. The native method of making ice is rather clever. A "yakh khaneh" or ice-house is generally situated outside the town or near some running water: a trench is dug some two or three feet deep, and a wall from twenty to forty feet is built facing north and south, thus shielding the trench from all rays of the sun. As soon as frost sets in, an inch or two of water is let into the trench: this freezes during the night, and the next day more water is diverted into the hole, on top of the ice. This is repeated several days in succession, till about a foot or more of ice is formed. This is then broken up and stored in deep caverns or wells for use during the summer. The process is continued as long as the frost lasts, and thus there is generally enough to keep the town supplied with ice during the great heat. Well-to-do Persians have their own "yakh khanehs," and others use them for a means of livelihood. If the supply runs short before the hot season is over, frozen snow is brought from the mountains; but this is very expensive, as it has to be brought such a long distance. Yezd has a much warmer "hot season" than Isphahan, and the heat is much more trying and of longer duration. The houses are essentially summer houses. The winters being shorter and much less severe, little attention is paid to the comforts necessary for cold weather, but everything is considered which will add to the coolness and airiness of the houses. As a traveller approaches Yezd he cannot fail to be struck by the number of tall "chimneys" rising from the city, and he almost fancies he is approaching some large manufacturing town, and speculates perhaps as to the nature of the manufactures possible in such a sandy city of the desert. But as he draws nearer he sees there is no smoke rising from these "chimneys," and so concludes that, after all, they are not for manufacturing purposes. What, then, is the purpose of all those tall, square, chimney-like buildings, appearing from the roofs of nearly all the dwelling-places of Yezd? They are air shafts, built with the hope of bringing a little cool air into the houses during the hot season, when the atmosphere below is so stifling that it seems impossible to breathe. These structures are called "bad geers," or "wind-catchers." There was a very large one connected with the house in which we lived in Yezd, and even on the hottest days, some air was always to be felt coming from the "bad geer." It was so arranged in our house that after the air had been caught and brought down by means of the chimney, it passed over a "hoze" (tank of water), and in this way was cooled before circulating through the house. Another aid to bearing the heat in Yezd is the custom of spending the middle part of the day underground in cellars.