Entering by the pipe _t_, Fig. 15, the undistilled liquid or "wash" is distributed over a perforated plate _y y_, and falls in drops into the condenser _E_, where it is heated by contact with the coil _S_ containing the heated vapors. The condenser is divided into two compartments by a diaphragm _X_ which is pierced with holes at its lower extremity; through these holes the wash flows into the second compartment, and passes out at the top, where it runs through the pipe _h_, into the top of the column _C_. The vapors are made to traverse the coil _S_, which is kept at an average temperature of 122∞ F., in the right hand compartment, and somewhat higher in the other. They pass first through _J_ into the hottest part of the coil, and there give up much of the water with which they are mixed, and the process of concentration continues as they pass through the coil. Each spiral is connected at the bottom with a vertical pipe by which the condensed liquors are run off; these are conducted into the retrograding pipe _p p_. Those which are condensed in the hottest part of the coil, and are consequently the weakest, are led by the pipe _L_ into the third vessel in the column _D_, Fig. 16, while the stronger or more vaporized portions pass through _L¥_ into the fifth vessel. Stop-cocks at _m_, _n_, _o_ regulate the flow of the liquid into these vessels, and consequently also the strength of the spirit obtained. Lastly, as the highly concentrated vapors leave the coil _S_ at _R_, they are condensed in the vessel _F_, which contains another coil. This is kept cool by a stream of liquid flowing from the reservoir _H_ into the smaller cistern _G_ from which a continuous and regular flow is kept up through the tap _v_ into a funnel _N_ and thence into condenser _F_. It ultimately flows into condenser _E_ through pipe _t_, there being no other outlet. The finished products run out by pipe _x_ into suitable receivers. It will be seen that the condenser _E_ has two functions. First it condenses the alcoholic vapors before transmitting them to the final condenser _F_, rejecting and sending back those vapors which are not highly enough vaporized. Second it heats the wash intended for distilling by appropriating the heat of the vapors to be condensed. Thus two birds are killed with one stone. It will be noticed that the same result is accomplished in the columns _C_ and _D_. This is the principle of all modern stills. Another form of still which is very analogous to that last described is Coffey's apparatus, shown in Fig. 18, and is the immediate prototype of the stills used to-day in all but the simplest plants. [Illustration: FIG. 18.--Coffey's Rectifying Still.]