Ferric ChlorideHospitality The hostess apologized to her unexpected guest for serving an apple-pie without any cheese. The little boy of the family left the room quietly for a moment and returned with a piece of cheese which he laid on the guest's plate. The visitor smiled, put the cheese into his mouth and then said: "You must have better eyes than your mother, sonny. Where did you find the cheese?" "In the rat-trap, sir," replied the boy.
Waste water treatment