What's the difference between gastromancy and ventriloquism?

Gastromancy

Definition:

(n.) A kind of divination, by means of words seemingly uttered from the stomach.
(n.) A species of divination, by means of glasses or other round, transparent vessels, in the center of which figures are supposed to appear by magic art.

Example Sentences:

Definition:

(n.) The act, art, or practice of speaking in such a manner that the voice appears to come, not from the person speaking, but from some other source, as from the opposite side of the room, from the cellar, etc.

Example Sentences:

(1) In these experiments, the ventriloquism effect was observed for conditions in which the subject turned his eyes 30 degrees to watch a speaker on a TV monitor.
(2) The findings are discussed in connection with the 'visual capture' or 'ventriloquism' effect.
(3) The "ventriloquism effect" refers to the perception of speech sounds as coming from a direction other than their true direction, due to the influence of visual stimuli from an apparent speaker.
(4) It was found that (1) the ventriloquism effect could be obtained for (hidden) auditory sources 20-30 degrees from the position of the TV speaker; (2) a strong ventriloquism effect could be obtained for an auditory stimulus at an angel of 150 degrees right of the subject's straight ahead when the TV source (toward which the subject's gaze was directed) was at 30 degrees right of straight ahead.
(5) Born to working-class parents in Newark who moved in the late 1960s to the suburb of Livingston, Christie's appeal is also rooted in something harder to put one's finger on, what Benjamin Wallace-Wells calls the "precision of his cultural ventriloquism".
(6) Edugyan's ventriloquism is compelling, personal and authentic, her story deeply researched.