_Separation of the oil and water._--As previously mentioned the specific gravity of most volatile oils is less than that of water. This behavior is utilized for the separation of the oil and water, by means of a so-called Florentine flask (Fig. 7). It consists of a glass flask provided near the bottom with a pipe, _a_, rising vertically to near the neck _c_ of the flask where it is bent downwards as shown in the illustration. The mixed liquid of water and oil drips from the cooling pipe into the flask, and the water _w_, being specifically heavier, separates from the oil floating on the top, and gradually ascends in the pipe _a_, finally flowing over at _d_. Oils specifically heavier than water are caught in receivers provided with a discharge-pipe near the mouth of the flask as shown in Fig. 8. [Illustration: FIG. 7.] [Illustration: FIG. 8.] The oil delivered from the receivers is, however, still mixed with some water, dirt, etc., and for their separation is allowed to stand quietly for some time. The final separation is effected either by simply pouring off the oil, especially if larger quantities have to be handled, or with the assistance of a separator-funnel (Fig. 9). This consists of the glass-funnel _T_ secured to the stand _G_, and provided with a close-fitting lid, _P_. The fluid is poured into the funnel, the lid placed in position, and the whole allowed to rest until the water _W_ is completely separated from the oil _O_. The oil is then separated from the last drops of water by carefully opening the faucet _H_. Most volatile oils are obtained by distillation, but this method is not practicable for separating the odoriferous principle of many of the most sweet-scented and delicate flowers, partially because the flowers contain too little oil, and partially because the oil would lose in quality if obtained by distillation. [Illustration: FIG. 9.]