Within the trabeculae of the sponge-work blood circulates, and between the trabeculae the water passes,.
In its original form, this consists of a long tube surrounded by an outer tube so arranged that cold water circulates in the annular space between the two.
Of other common types of condenser, we may notice the "spiral" or "worm" type, which consists of a glass, copper or tin worm enclosed in a vessel in which water circulates; and the ball condenser, which consists of two concentric spheres, the vapour passing through the inner sphere and water circulating in the space between this and the outer (in another form the vapour circulates in a shell, on the outside and inside of which water circulates).
Three types of columns are employed: (I) the elongation is simply a straight or bulb tube; (2) the column, properly termed a "dephlegmator," is so constructed that the vapours have to traverse a column of previously condensed vapour; (3) the column is encircled by a jacket through which a liquid circulates at the same temperature as the boiling-point of the most volatile component.
The Weir, the condensing water circulates upwards through the tubes; in others, e.g.