rth German Lloyd and the Hamburg American
companies.

The modern distilling plant consists of two main parts termed the
evaporator and condenser; in addition there must be a boiler
(sometimes steam is run off the main boilers, but this practice has
several disadvantages), pumps for circulating cold water in the
condenser and for supplying salt water to the evaporator, and a filter
through which the aerated water passes. The evaporator consists of a
cylindrical vessel having in its lower half a horizontal copper coil
connected to the steam supply. The cylindrical vessel is filled to a
certain level with salt water and the steam turned on. The water
vaporizes and is led from the dome of the evaporator to the head of
the condenser. The water level is maintained in the evaporator until
it contains a certain amount of salt. It is then run off, and replaced
by fresh sea-water. The condenser consists of a vertical cylinder
having manifolds at the head and foot and through which a number of
tubes pass. In some types, e.g. the Weir, the condensing water
circulates upwards through the tubes; in others, e.g. the Quiggins,
the water circulates around the tubes. Various forms of the tubes have
been adopted. In the Pape-Henneberg condenser, which has been adopted
in the German navy, they are oval in section and tend to become
circular under the pressure of the steam; this alteration in shape
makes the tubes self-scaling. In the Quiggins condenser, which has
been widely adopted, e.g. in the "Lusitania," the steam traverses
vertical copper coils tinned inside and outside; the coils are
crescent-shaped, a form which gives a greater condensing surface and
makes the coils self-scaling. The aeration of the water is effected by
blowing air into the steam before it is condensed; as an auxiliary,
the storage tanks have a false bottom perforated by fine holes so that
if air be injected below it, the water is efficiently aerated by the
air which traverses it in fine streams. After condensation the water
is filtered through charcoal. The filter is either a separate piece of
plant, or, as in the Quiggins form, it may be placed below the coils
in the same outer vessel. In this plant the aeration is conducted by
blowing in air at the base of the condenser. After filtration the
water is pumped to the storage tanks. Many types of distilling plant
are in use in addition to those m