the difficulty of representation
discussed at (pp 32-35).
“Another consideration which must not be forgotten is the type of matter in which these forms are generated. If a thought be purely intellectual and impersonal—for example, if the thinker is attempting to solve a problem in algebra or geometry—the thought-form and the wave of vibration will be confined entirely to the mental plane. If, however, the thought be of a...”
more (less diagrammatic than this) here.
Epigram from second chapter, in which
“We have often heard it said that thoughts are things, and there are many among us who are persuaded of the truth of this statement. Yet...”
color; meaning; whiteness (absence) / Highest Intellect; A. Besant and C. W. Ledbeater, Thought Forms (1905)