Sri Aurobindo
Letters on Yoga
5. Planes and Parts of the Being
Fragment ID: 284
That is the original Tapoloka in which the principle is Chit and its power of Tapas, but there are other worlds of Tapas on the other planes below. There is one in the mental, another in the vital range. It is one of these Tapas worlds from which the being you saw must have come.
Current publication:
Sri Aurobindo. Letters on Yoga // SABCL.- Volume 22. (≈ 28 vol. of CWSA).- Pondicherry: Sri Aurobindo Ashram, 1971.- 502 p.
Other publications: