tion]

Few have done more, perhaps none so much, as Dr. Normandy to make sea
water distillation not only a success as a source of water supply, but
also to supply it at a minimum cost for fuel. He by a peculiar
arrangement of pipes embodied something of the regenerative system in his
apparatus, using the heat taken from one lot of steam to generate more,
and again the heat from this he used over again. The defect of his older
arrangements was undue complexity and consequent trouble to keep in
order.

As can be well imagined, the distillers in use at Suakim are on a much
more colossal scale, and owing to the now almost universal use of surface
condensers in ocean steamers, no great difficulty ought to attend the
adaptation of the boilers and condensers of one of our transports. One of
these full-powered steamers will indicate, say, 5,000 horse-power, and
assuming her engines to use 25 lb. of steam per indicated horse-power, or
21/4 gallons, she could distill some 12,000 gallons of water per hour. As
no appreciable pressure of steam need be maintained, the boilers would
suffer little from deposit, especially if regularly blown out. Hard
firing need not be resorted to; indeed, it would be injudicious, as, of
course, priming must be carefully guarded against. Of course, the salt
water distilled will affect the working, not exactly of the distillers,
but of the boilers. If the water in the harbor, as is not improbable, is
muddy, some method of filtering it before pumping it into the boilers
ought, if at all practicable, to be resorted to, for the twofold reason
of preserving the boiler plates from muddy deposit, and also to prevent
priming, which would certainly ensue from the use of muddy water. No
doubt the medical staff take care that the distilled water is alike
thoroughly aerated and efficiently filtered. The most successful method
of aerating is, we believe, to cause the current of steam as it enters
the condenser to suck in air by induced current along with it. The
filtering ought not to present any difficulty, as at all events sand
enough can be had. Charcoal, however, is another affair, and all
distilled water ought to be brought into contact with this substance.

Simple, however, as such an arrangement as this appears to be, practical
difficulties, which it is _said_ are insurmountable, stand in the way of
its adoption, and the distilled water produced for Egypt is made in
special apparatus, and various forms of