Acquire the shell of a conch, which will serve as a receiver for signals from the communications which you will intercept.

Acquire, secondly, water from a body of water upon which others depend. Oceans, large lakes, and seas will serve you better than will rivers and tap water. From this water you may extract the spirit of the Undine (or water spirit) by calling it into your cup while you have the same set upon your disk or pentacle.

You may relate to the Undine in whatever way appeals to you...conjure it by the Queen Nichsa of the Undersea Citadel, by angels of the watery spheres, by the holy words used by gods to turn back the tides, or by any other method by which you choose to obtain dominion over the spirits of the element of water.

When the Undine manifests in the water of your cup, direct it with magic words and signs to enter into your conch shell, that it may speak to you in the sounds of the surf to answer questions which you may ask of it. Give it a name by which you may call it.

Pour the cup's contents out into the shell, instructing the undine to remain there so long as the shell remains intact.

When you wish to know of some conversation, or to hear the words which pass without speech from a person to himself, or when you wish to hear of what transpires in some place, call the name of the Undine into the shell, and ask it your questions. It will respond in the background of the noise of surf which all shells exhibit.

Footnote:
Undines were considered water elementals, responsible for comforting and seducing human souls. The trouble with them seemed to be the fact that they were somewhat vampiric in this task, and were prone to emotional clingyness. Hence the need for sticking it in its place and making it serve you according to your own terms.