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 that he could compel the sunbeams to paint a portrait, he would in all probability have been burned as a wizard; indeed, not many years ago a gentleman was thought to be disordered in his intellect, because he deemed it possible to fix the fleeting pictures seen in the camera obscura.

We cannot enter further into the Magic of the Sunbeam without leading our readers into the mystic regions of mathematics. We have already said that the subject is an inexhaustible one, and we are more convinced of this than ever when we find what a comparatively small number of facts relating to the wonderful band of forces called the sunbeam, we have been able to set before the reader. But though so much is known about the sunbeam, how much still remains obscure! It is only lately that the existence of the mighty principle of actinism has been revealed; and who can tell what forces may still be hidden in the beam—what unknown powers may yet be brought to light by our laborious truth-seekers?