nce in the equipment of ships. The simple
distillation of sea-water, and the production thereby of a certain
proportion of chemically fresh water, is a very simple problem; but it
is found that water which is merely evaporated and recondensed has a
very disagreeable flat taste, and it is only after long exposure to
pure atmospheric air, with continued agitation, or repeated pouring
from one vessel to another, that it becomes sufficiently aerated to
lose its unpleasant taste and smell and become drinkable. The water,
moreover, till it is saturated with gases, readily absorbs noxious
vapours to which it may be exposed. For the successful preparation of
potable water from sea-water, the following conditions are
essential:--1st, aeration of the distilled product so that it may be
immediately available for drinking purposes; 2nd, economy of coal to
obtain the maximum of water with the minimum expenditure of fuel; and
3rd, simplicity of working parts, to secure the apparatus from
breaking down, and enable unskilled attendants to work it with safety.
The problem is a comparatively old one, for we find that R. Fitzgerald
patented a process in 1683 having for its purpose the "sweetening of
sea-water." A history of early attempts is given in S. Hales's
_Philosophical Experiments_, published in 1739. Among the earlier of
the modern forms of apparatus which came into practical adoption are
the inventions of Dr Normandy and of Chaplin of Glasgow, the apparatus
of Rocher of Nantes, and that patented by Galle and Mazeline of Havre.
Normandy's apparatus, although economical and producing water of good
quality, is very complex in its structure, consisting of very numerous
working parts, with elaborate arrangements of pipes, cocks and other
fittings. It is consequently expensive and requires careful attention
for its working. It was extensively adopted in the British navy, the
Cunard line and many other important emigrant and mercantile lines.
Chaplin's apparatus, which was invented and patented later, has also
since 1865 been sanctioned for use on emigrant, troop and passenger
vessels. The apparatus possesses the great merit of simplicity and
compactness, in consequence of which it is comparatively cheap and not
liable to derangement. It was adopted by many important British and
continental shipping companies, among others by the Peninsular &
Oriental, the Inman, the No