US1749090A: Apparatus for obtaining criminal confessions and photographically recording them:The primary object of my invention is the provision of an apparatus for the creation of illusory efiects calculated to impress the subject with their being of a supernatural character and to so work upon his imagination as to enable an inquisitor operating in conjunction with-the recording system to obtain confessions and graphically record them by light action under the control of electric impulses governed by varying intensities of sound waves. [...]
The skeleton 16 is arranged in front of the panel 8, with its feet resting upon the glass top of the light chamber 14, the lights 27 mounted in this chamber being adapted to flood the entire skeleton from the feet up, while a second source of light 28 mounted upon the panel 8 over the skull of the skeleton, as shown in Figure 1, is adapted for additional flooding from an opposite direction, the purpose being to produce the appearance of an apparition having a translucent outer, or astral body, and a diaphanous veiling constituting the so-called aura, the lighting being of a character adapted to flood with a ghostly light and to bring out clearly the skeleton's outlines. To add to the mystification, the bulbs 22, forming the eyes of the skeleton, will be caused to blink, upon the subjects replying to questions while under examination, this blinking resulting from the variations in the sound waves as governed by the microphones controlling the electric circuits; [...]
The light bulbs 22 are of either the usual evacuated order, or gas filled, but differ in that one-half of the bulb is of blue color, while the other half is of red, to meet the double requirements of the emitted light, the blue being used as better adapted for the recordation of the sound waves, and the red for the purpose of imparting to the eyes of the skeleton an unnatural ghastly glow. [...]
A megaphone 32 is arranged for the convenience of the examiner, in questioning a suspect, the outer end of said megaphone being connected to the skull of the skeleton in such manner that the voice of the operator appears to come from the mouth of the skeleton.
Turns out that inventor Helene Adelaide Shelby was from Oakland and filed this in 1927 - I can only assume she did so after reading/seeing A Christmas Carol and thinking, "Boy, those ghosts sure shook down Scrooge somethin' good, I tell ya what!"
See Tom Scott's We Built a Lie-Detector Skeleton from 1927 if you want to see it in action.
That was hilarious, thank you.