[1] We must caution the young reader against some of the views given in M. Salverte’s work. In his anxiety to account for everything miraculous by natural causes, he has ascribed to the same origin some of these events in sacred history which Christians cannot but regard as the result of divine agency.
[2] When both eyes are open, the object whose image falls upon the insensible spot of the one eye is seen by the other, so that, though it is not invisible, yet it will only be half as luminous and, therefore two dark spots ought to be seen.
[3] A very curious example of the influence of the imagination in creating distinct forms out of an irregularly shaded surface, is mentioned in the life of Peter Heaman, a Swede, who was executed for piracy and murder at Leith in 1822. We give it in his own words:—
“One remarkable thing was, one day as we mended a sail, it being a very thin one, after laying it upon deck in folds, I took the tar brush and tarred it over in the places which I thought needed to be strengthened. But when we hoisted it up, I was astonished to see that the tar I had put upon it represented a gallows and a man under it without a head. The head was lying beside him. He was complete, body, thighs, legs, arms, and in every shape like a man. Now, I oftentimes made remarks upon it, and repeated them to the others. I always said to them all, You may depend upon it that something will happen. I afterwards took down the sail on a calm day, and sewed a piece of canvas over the figure to cover it, for I could not bear to have it always before my eyes.”
[4] See the Edinburgh Encyclopædia, Art. Accidental Colours.
[5] Edinburgh Journal of Science, New Series, No. iv. pp. 218, 219, No. vi., p. 244, and No. viii., p. 261.
[6] Inquiries concerning the Intellectual Powers, and the Investigation of Truth. Edinburgh, 1830.
[7] Ut speculum in loco certo positum nihil imaginet; aliorsum translatum faciat imagines. Aul. Gel. Noct. Attic., lib. xvi., cap. 18.
[8] See Edin. Encyclopædia, Art. Optics, Vol. xv., p. 611.
[9] Page 86.