STEAM-SHIPS FOR THE CHANNEL PASSAGE. 
7 ; 
of the man operating the apparatus, notwithstanding that the 
vessel in which it rests is moving beneath it. 
“ In order to effect this end, a toothed sector of large 
diameter is secured to the main central axis of the structure, 
and beneath it is a strong bed-plate firmly attached to the floor 
of the ship. On this bed-plate are two hydraulic cylinders, to 
which a double-ended ram is fitted, the central part of the 
ram being provided with teeth, which gear into the sector. 
Therefore when the ship is in a state of rest, the sliding in 
and out of the rams will cause the saloon to move on its own 
axis with a gentle but powerful motion. These movements, 
however, are controlled by a pair of delicately-balanced equili- 
brium valves. 
‘‘ Hence it will be seen, that when the ship is rolling at sea, 
this power of acting on the saloon enables the steersman to retain 
the saloon constantly in a perfectly vertical position, while the 
floor of the ship is rising and falling beneath it. The essential 
point of this arrangement is that the hydraulic apparatus has not 
to put the saloon in motion, but simply to prevent it acquiring 
any motion. Moreover, the vis inevtice of a structure like the 
saloon, which ynll weigh some seventy or eighty tons, will 
greatly assist in resisting the initial tendency to motion. 
“ In other respects Mr. Bessemer’s saloon offers undoubted 
advantages. Besting, as it will, on four axial supports bedded 
on an elastic packing of large area, it will be completely 
insulated, and will not be susceptible of the violent tremulous : 
motion imparted by the engines and paddles. Again, the heavy 
shocks of the sea against the sides of the ship, so objectionable 
in cabins built against the framing of the vessel, will be wholly 
unfelt, as there will be a space of five feet between the saloon 
and the sides of the ship, from which, in fact, it will be totally 
disconnected.” 
Fig. 1 of Plate XCII. is a section of the ship taken right 
through the saloon. The strong black line shows the moving 
part. 
It will be observed that the attempt to neutralise the motion 
of the vessel by that of the saloon addresses itself to the 
rolling only. It does not affect either the translatory part of 
a ship’s oscillation, or the pitching. I agree with the pro- 
moters in thinking that, in such large vessels as they propose 
to usoj and with the saloon in the middle of the ship, the 
pitching will be small in amount, and slow; and that, taken, 
alone, it will not be sufficient to cause sea-sickness. There is,v 
however, another kind of motion affecting the ship, which 
requires fuller consideration. 
In the regular heaving of the sea, after the wind has blown 
sufficiently long to cause regular waves or swell, each particle 
