It creates a blanket of dry surface soil which insulates the soil moisture from the air above.
"A Living from the Land"
William B. Duryee
But, in truth, it must be impossible for any one who feels Balzac's power not to feel also how it is heightened by Balzac's absolute calm-a calm entirely different from that stern composure which was merely a point of style and not an attitude of the heart with the old Greek tragedians-a calm which, unlike theirs, insulates, so to speak, and is intended to insulate, the writer, to the end that his individuality, of which only the electric current of sympathy ever makes a reader conscious, may disappear, and the characters of the drama stand forth the more life-like from the complete concealment of the hand that moves them.
"Sterne"
H.D. Traill
From his own experience he knew that the abstraction of an experimenter insulates him from every outside contact.
"The Raid on the Termites"
Paul Ernst