lf during the past
decade of the nineteenth century for an increase of sailing tonnage.
Sooner or later, however, it will be recognised that sail power must
be largely supplemented, even on the "sailer," if it is to hold its
own against steam.

For mails and passengers, on the other hand, steam must more and more
decidedly assert its supremacy. Yet the mail-packet of the twentieth
century will be very different from packets which have "made the
running" towards the close of the nineteenth. She will carry little or
no cargo excepting specie, and goods of exceptionally high value in
proportion to their weight and bulk. Nearly all her below-deck
capacity, indeed, will be filled with machinery and fuel. She will be
in other respects more like a floating hotel than the old ideal of a
ship, her cellars, so to speak, being crammed with coal and her upper
stories fitted luxuriously for sitting and bed rooms and brilliant
with the electric light. But in size she will not necessarily be any
larger than the nineteenth century type of mail steamer. Indeed the
probability is that, on the average, the twentieth century
mail-packets will be smaller, being built for speed rather than for
magnificence or carrying capacity.

The turbine-engine will be the main factor in working the approaching
revolution in mail steamer construction. The special reason for this
will consist in the fact that only by its adoption can the conditions
mentioned above be fulfilled. With the ordinary reciprocating type of
marine steam machinery it would be impossible to place, in a steamer
of moderate tonnage, engines of a size suitable to enable it to attain
a very high rate of speed, because the strain and vibration of the
gigantic steel arms, pulling and pushing the huge cranks to turn the
shafting, would knock the hull to pieces in a very short time. For
this very reason, in fact, the marine architect and engineer have
hitherto urged, with considerable force of argument, that high speed
and large tonnage must go concomitantly. Practically, only a big
steamer, with the old type of marine-engine, could be a very fast one,
and, for ocean traffic at any rate, a smaller vessel must be regarded
as out of the running. Very large tonnage being thus made a prime
necessity, it followed that the space provided must be utilised, and
this need has tended to perpetuate the combination of mail and
passenger traffic with cargo carrying.

The first step towards the revo