If the shaft and tunnel were in place, however, the screen might follow as a matter of necessity. Entrance to the kivas is always through the roof, a ceremonial requirement quite as rigidly adhered to today among the Pueblos as it was formerly among their ancestors. The same opening which gives access also provides an exit to the smoke from the fire, which is invariably placed in the center of the kiva below it. This fire is a ceremonial rather than a necessary feature, for in the coldest weather the presence of a dozen men in a small chamber, air-tight except for a small opening in the roof, very soon raises the temperature to an uncomfortable degree, and the air becomes so fetid that a white man, not accustomed to it, is nauseated in half an hour or less. Such are the conditions in the modern kivas of Tusayan. In the smaller structures of De Chelly they must have been worse. The fire is, therefore, made very small and always of very dry wood, so as to diminish as far as possible the output of smoke. Frank H. Cushing states that in certain ceremonials which occur in the kivas it is considered very necessary that the fire should burn brightly and that the flame should rise straight from it. If this requirement prevailed in De Chelly, a screen of some sort would surely follow the construction of a shaft and tunnel. More or less smoke is generally present in the kivas when a fire is burning, notwithstanding the care taken to prevent it. That a similar condition prevailed in the kivas of De Chelly is shown by the smoke-blackened plaster of the interiors. In some cases there was a room over the kivas which must have increased the difficulty very much. There can be little doubt that the chimney-like structures were not chimneys, and no doubt at all that they did provide an efficient means of ventilation, no matter what the intention of the builders may have been. When we know more of the ceremonials of the Pueblo Indians, and when extensive excavations have developed the various types and varieties of these structures in the ruins, we may be able to determine their object and use. TRADITIONS