Light is the power that enlightens whatever it falls upon - the result may be vision, memory, knowledge, right will, right impulse, etc.
A descent brings naturally a deep inward condition and a silence of the mind, and it may bring much more - peace, a sense of liberation, happiness, Ananda. It is very often attended as in this experience by a light or luminosity. It was felt enveloping the upper part of the body down to the cardiac centre, because it is these centres, the head and heart centres that are first invaded and occupied by whatever descends from above, Consciousness, Force, Light or Ananda. Usually, there is at first a pressure from above on the head, then one feels something entering the higher part of the head and then the whole head is occupied, as you feel now with the ‘‘fourmillement’’ at the time of concentration. Once the head with its mental centres is open and occupied, the Force descends rapidly to the heart centre, unless there is some obstacle or a resistance in the higher vital parts. From there it sends its stream into the whole body and begins to occupy the vital and physical centres--from the nave1 to the Muladhara. The coming of this experience, occupation of the body, by the Force from above, is a great step forward in the sadhana.
All Light is not the light of the spirit, much less the light of the supermind. The mind, vital and physical have their own lights which can be very exhilarating and aspiring.
More and more souls shall enter into light,
Minds lit, inspired, the occult summoner hear
And lives blaze with a sudden inner flame
And heart grow enamoured of divine delight
And humans wills tune to the divine will.