12 
POPULAE SCIENCE EEVIEW. 
pearls or oysters_, nor to fisli up treasures from tlie ooze and 
bottom of the deep. No customers are there for Manchester 
cottons or Lyons silks; gold from California and Yankee 
greenbacks in those cold green depths would be alike at par ; 
and even a cargo of Popular Science Eeviews would find no 
readers amongst the foraminifera and star-fishes of the ocean 
floor. We have said such a ship never could be meant for any 
good. Nor is she. Her designer, M. Bailer, intended her 
solely to play mischief with other ships, and to plant torpedos 
for blowing up an enemy. Such a vessel has been actually 
constructed, we believe, in our own dockyards, and practically 
worked at one hundred feet under water for two hours ; but 
the close of the Eussian war rendering the use of such amphi- 
bious craft no further necessary, the public have heard little or 
nothing about her ; although it is said that Lord Palmerston 
and the late Prince Albert took great interest in the matter. 
M. Bailer is, we believe, a Prussian; and it is, we are in- 
formed, upon his plan that the Eussian Government are now 
constructing a submarine vessel at the cost of £27,000 : we are 
much disposed to think, however, that for want of complete 
develojtment this vessel may not answer, but there is no doubt 
that English engineers could construct submarine vessels cap- 
able of remaining under water from ten to twenty hours at 
depths not exceeding 120 feet. Such vessels might be of any 
size, and would be capable of effecting an enormous and 
unheard of amount of mischief. 
The designs for such a vessel would be kept as secret as 
possible ; but the general fundamental principles may be easily 
explained. Suppose an iron vessel. She floats because her 
entire internal cubical capacity being filled with air, her weight 
displaces a less bulk of water than her own dimensions. Now 
close up every hatchway and entrance ; hermetically seal in, as 
it were, the air ; and leave only a pipe and valve by which the 
exit of any of the contained air may be controlled or stopped 
altogether. Open the valve. Now, by means of another valve, 
let into her hull water from the sea. As the water comes in 
the air is pressed out. She begins to sink, goes gradually 
down, — ten, twenty, forty, fifty, a hundred feet. Shut up the 
air- valve ; shut up the water- valve. She is exactly now of 
the same specific gravity as the water in which she is sub- 
merged. She will not rise ; she will not sink. Set the 
engines at work upon her screw-propeller. She progresses. 
Through thick glass bulhs-eyes in her decks, men watch the 
sea-scape above them. The dark bottom of some huge ship 
blots out the dim light from above. The submarine 
*is lightened, rises slowly ; submarine sailors in submarine 
helmets and clothes come on the submarine deck, the torpedo 
