Any one who is at all familiar with the optical illusions and scenic effects which form a favourite portion of some of our public exhibitions, must be convinced that the art of producing these phenomena, with their various and mind-bewildering play of colours and change of character, has attained great perfection. But probably few persons are in the least degree acquainted with the manner in which the appearances they be much admire are produced. It will therefore be possibly an interesting subject to many, if we glance first at the optical phenomena themselves, and then proceed to explain the method of their production.