Thank you for your polygraph articles: they are most informative. However, I challenge the notion that the skin-galvanometer readings are caused by sweat gland activity and evaporation.

Back in 2009 I made several videos concerning skin galvanometer use, mostly for demonstration or experimentation for a particular audience. I haven't put one to “real use” outside of this since 2005 or so. This particular video was made to challenge an individual called “Anon Orange”. I only state this because I say his name aloud. The other terminology should be clear enough in context.

This is a two-minute video, showing a skin galvanometer read-out. The two wires coming out of the machine normally connect directly to the skin, of course. Here they dangle in two separate cups of water. I then stick my fingertips underwater in each cup, an inch or so away from the submerged wires, and am very careful to keep them still on the bottom of the cups so the amount of submerged skin does not change. I'm leaving out hopefully-unnecessary details.

The underwater needle activity seems to be very similar to how it normally appears with the electrodes directly touching my skin, except the amplitude is about 10% that of in-air contact.

Of course it is a very sloppy experiment. But can you explain how sweat could possibly produce that result across an inch or so (and several inches in other videos) of water?