Asana is concerned with the static aspect of the body. Pranayama is really the control of the dynamic aspect of the body.
Here we have a Niyama of infinite delicacy, a spiritual intuition far, far removed from any human quality whatever. Here all is fantasy, and in this world are infinite pleasure, infinite perils. The True Niyama of Neptune is the imaginative faculty, the shadowing forth of the nature of the illimitable light.
He has another function. The Yogi who understands the influence of Neptune, and is attuned to Neptune, will have a sense of humour, which is the greatest safeguard for the Yogi. Neptune is, so to speak, in the front line; he has got to adapt himself to difficulties and tribulations; and when the recruit asks 'What made that 'ole?' he has got to say, unsmiling, 'Mice.'
Pluto is the utmost sentinel of all; of him it is not wise to speak.
The True Niyama of Neptune is the imaginative faculty, the shadowing forth of the nature of the illimitable light.