it was but a single ray at first , a taut string of light extending between the earth and the clouds as if the sky was an immense kite of rosy grey but then this up till that moment seemingly unbreakable fabric began to slowly tear , and thin out like windswept smoke , so that the ray thickened into a beam and then into a column and finally , as the initial break in the firmaments mantle grew into a gaping , still-widening hole , into a tall luminous pillar that shed a blissful warmth to the air and the ground it lit up .