The term "rectified" in connection with distilled spirits at the present time is used in a double sense. Strictly speaking it means a spirit which has been purified in some way by redistillation or otherwise. In the process of distillation the character of the distillate varies greatly with the rapidity of the distillation and the shape of the still. Where stills are very large, very high, with large throats, and where the distillation is carried on at a reasonable speed, the distillate comes over in a very satisfactory condition. If, on the other hand, the still is small, with small throat, and the distillation is rapid, a great deal of material is carried over mechanically, as well as by the high temperatures, which give bad flavor and odor to the whisky. Such distillates are often purified either by the addition of a substance like sulphuric acid, which combines with the more undesirable impurities, and renders them non-volatile, so that they can be separated on a subsequent distillation, or the purification may take place by redistillation itself. To this end there was invented what is known as the chambered still. This still may be regarded as a large number of small stills constructed one upon the other. The spirit to be purified is placed in the bottom still or compartment and volatilized usually by means of steam coils. The spirit passes into the next still through a peculiar form of aperture whereby a portion of it when condensed must remain upon the floor of the still. As soon as the second compartment enters into activity a second distillation begins, and so on until all the still is filled. The steam is applied only in the lower compartment.

These stills often have from 10 to 40 chambers, and range in height from 20 to 70 feet.

At each distillation a more pure spirit is secured until finally at the top there is scarcely anything left but pure ethyl alcohol.

I will not stop here to describe the technique of the construction, but simply to illustrate its principle. It follows from the above that, as the spirit becomes more and more pure, that is, in essence consisting solely of ethyl alcohol, it becomes less and less like whisky. Finally, provided the spirit has previously been filtered through charcoal and further purified by a process of separation of the parts that come off first and the parts that come off last, a very pure spirit is secured, which is known to the trade by such names as "cologne spirit," "velvet spirit," "neutral spirit," "silent spirit," etc., already defined. This spirit has lost all the characteristics of a whisky and can in no way be considered as whisky in the beverage sense of that term. In the process of making whisky the spirits are subjected to two distillations, one to separate the spirits from the beer, and the other to double and concentrate the spirits so as to make its alcoholic strength greater. Then it is placed in casks and put away to age.