Reprinted from a 1927 wireless magazine

Christmas 1927: Ideas for Xmas Entertainment

Three parlour tricks from the golden age of the wireless set, for when the festivities are flagging.

The original magazine heading

For amusement only. These experiments involve potentially lethal voltages. Do not try any of them.

The Dancing Guest

Fig. 1. Two handles wired to the secondary of an intervalve transformer

If the festivities are somewhat dull, why not try to make the guests dance? Not by the obvious method of turning on the dance music and leaving the guests unentertained until, in sheer desperation, they dance for diversion, but in a much more unusual way.

Produce two metal handles, made of sheet metal roughly rolled into a tube an inch or so in diameter and connected by a piece of flex to the secondary terminals of a step-up intervalve transformer. Join the primary terminals in parallel with the loud-speaker, and bring up the music to maximum volume. Anyone holding the handles will receive quite energetic shocks in time with the music, and if your victim is either sensitive or unusually frivolous he may perhaps execute an impromptu grotesque dance.

Music Without Telephone or Loud-Speaker

Fig. 2. Back to back, with a sheet of brown paper between the ears

With the handles still available, connect them to the output terminals of the receiver. A very simple yet mystifying experiment can be undertaken. Two persons are seated back to back, each grasping one of the handles from the set. A third person places a dried piece of brown paper between the ears of the seated persons, and it is rather surprising that this simple arrangement gives “telephone reception.”

The brown paper being dry, and consequently a good insulator, the possibility of feeling a “shock” need not be feared.

Human Telephone Leads

Fig. 3. A chain of guests carrying the signal to the loud-speaker

The comparatively low electrical resistance of the human body is well illustrated by feeding the signals between the output terminals and loud-speaker through a chain of persons. Good connection should be made at the terminals of both the set and loud-speaker by increasing the area of contact with a piece of metal to serve as handles.

This experiment is only successful with a loud-speaker of the high-impedance type.