Victor Hugo,
Les Misérables — Volume 4, Book Twelfth…
“ A glass door is an excellent thing in a barricade. It does not prevent an attack, but it prevents the enemy taking it. So you've never prigged apples over a wall where there were broken bottles? A glass door cuts the corns of the National Guard when they try to mount on the barricade. Pardi! glass is a treacherous thing. ”
