"For the meter to be read, the tiny flow of electrical energy through the preclear (person) has to remain steady. When this tiny flow is changed the needle of the E-Meter moves. This will happen if the preclear pulls in or releases mental mass. This mental mass (condensed energy), acts as an additional resistance or lack of resistance to the flow of electrical energy from the E-Meter."
Oh and mental mass is:
"In Scientology it has been discovered that mental energy is simply a finer, higher level of physical energy. The test of this is conclusive in that a thetan "mocking up" (creating) mental image pictures and thrusting them into the body can increase the body mass and by casting them away again can decrease the body mass. This test has actually been made and an increase of as much as thirty pounds, actually measured on scales, has been added to, and subtracted from, a body by creating "mental energy."
This machine is a basic lie detector and by that I mean a very very very basic lie detector, in other words it does not work. For that matter lie detectors don’t work, and this is a bad lie detector so do the math. It "works" by measuring the skin resistance/conductivity and as such can apparently be used to measure your spiritual impediments or mental energy. OK, so what this means is it can measure if you are releasing your past life baggage as you strive to become a clear. A clear is a person who has relieved themselves of unwanted memories and traumas...you know things like birth trauma.
In other words the crazies use it to manipulate you to get you to give up deep dark secrets that you don’t want people to know. Remember this is confidential between the auditor (priest) and you. By confidential I mean they do tape it and have it as back up...... in case you maybe want to leave the cult.
The Vice squad even played around with one, and made up rubbish around it as it does not work. I has even been labelled pseudo science by real scientists, not Scientologists. BTW Scientology is a name that means nothing scientific except science fiction.
So hey if you get asked to do an audit, do it and drive these fools crazy by saying you were Xenu in your last life. :)