This appears to be the first experiment in signalling on a subaqueous wire.
In his eagerness he had struck a subaqueous pipe of the jet.
Considering the large area, no subaqueous tunnel had ever been driven with such speed.
There are two important secondary techniques for opening subterranean and subaqueous ways, neither a method truly of tunneling.
This is the “trench” method, a sort of subaqueous equivalent of cut and cover.
The methods of construction employed were novel in subaqueous tunneling and are partly shown on photographs on pages 62 and 63.
Its subaqueous nest is in fact a sort of diving-bell, and constitutes a secure and most ingenious habitation.
It had been estimated that there are probably two thousand aerial or subaqueous eruptions every century.
Once, indeed, the raft grounded upon a subaqueous reef, and threatened going to pieces.
Subaqueous mining is therefore one of the big problems which the mining engineer of the twentieth century must tackle.