Not only do these experts sound the regular calls with ear-piercing exactness, but actual tunes are often included in their repertoire.
The pipe or whistle is held with the bulb in the centre of the palm, the hole being towards the wrist.

The lobe to which the ring and lanyard are attached, serves simply as a handle.
In the diagram given, the black line indicates the "pipe" or call; the four faint horizontal lines, the notes, and the vertical bars, the time.
The roll indicated by the wavy line in the diagram is made by rapidly opening and closing the hand.

The gradual rise and fall is effected in the same way, but slowly.

The rattle is done by a quick movement of the tongue.
This diagram is furnished by an old boatswain.

As a rule, the calls are taught entirely by personal instruction, and it is believed that they have here been put into print for the first time.