See reverse lightning.
Steam is now admitted to the other end of the cylinder, and the operation repeated on the backward or return stroke.
During the return stroke the pressure on the front is unopposed.
This prevents the cutting edge of the tool from rubbing against the work during the return stroke.
The file should be kept in contact with the work continually, but on the return stroke the pressure should be relieved.
On the return stroke a similar operation takes place on the right hand side.
The floats are arranged so that they will offer no resistance on the return stroke.
In the second return stroke the burnt gases are expelled from the cylinder and the whole made ready to start afresh.
On the return stroke the burnt gases were discharged, just as a steam engine exhausts.
A forward stroke in pure water displaces portions of the water and the return stroke sends the body forward.
At the return stroke the exhaust steam escapes into the steam chest, and from there it passes into the low pressure cylinder.