The idea of sleeping “under the starry sky” may be beautiful and romantic, but the reality it refers to is less attractive. Anyone who sleeps outdoors at night is a defenseless target for all sorts of cosmic and telluric radiations in their raw state. Let me make it clear, though, that this danger comes only from the combination of sleep, night, and a lack of shelter… at night there are violent bombardments of invisible forces – spiritual, physical, electric, and magnetic – and an outdoor sleeper is in a state of absolute vulnerability to all of them.
Yet all is not lost for lovers of the outdoors. A handkerchief over one’s face is sufficient “to break up the concentration of attacking forces and ward off the assaults of the Invisible.”
There’s a great deal of strange, inspirational stuff in this book.