The Persians rank high in this respect, because they have studied the philosophy of enjoying the fumes of tobacco in their greatest purity. This they have attained by passing the smoke through water, and thus purifying it from the essential oil of the plant. The kaleon of the Persians, the hookah of Hindostan, the shishé of the Arabs, or the narghillé of the Turks, is an air-tight vessel partially filled with water, on the top of which is a bowl to contain the ignited tobacco. From this bowl a tube descends into the water, and the long and flexible pipe is inserted into the vessel above the level of the water. When the smoker begins to draw through the pipe, a partial vacuum is created in the vessel, which occasions the pressure of the external air to force the smoke of the tobacco downward through the small tube above mentioned into the water beneath, where, after losing its solid particles, it bubbles up into the vacant space above, and thence through the pipe to the mouth of the smoker. But ever since the peculiar and agreeable properties of this fragrant plant have been known, the ingenuity of its votaries has been excited to invent and improve the ways and means of obtaining the greatest amount of satisfaction from its use. In the earliest stages the pipe was made of one entire piece of clay, but soon the fact was established that this substance became so heated as to decompose the tobacco. Metallic and other pipes were tried, but still the same evil existed; until wood became the most popular material. But that being combustible, the flavor of the tobacco was deteriorated; and at last the arrangement was made of a stem of wood with a bowl of clay attached to it, to contain the ignited plant. The wood was a nonconductor of heat, capable of being constructed of any length, and moreover, easily cleaned, so that this was pronounced the great desideratum. The Turks have displayed the greatest refinement and taste in the manufacture of their long and beautiful chibouks or pipe-stems, to which they attach the amber mouth-piece, so agreeable to the lips and free from all impurities.