172 SENSORIAL FUNCTIONS. 



the diameter of half an inch at the same instant, other- 

 wise it could not be seen at the same view. 



The Rev. Dr. Dick, in his " Christian Philosopher/' 

 a work which should be read by all mankind, has calcu- 

 lated that a portion of the Castle of Edinburgh, equal 

 to 500 feet long, and 90 in height, occupies on the retina 

 only the twelve hundred thousandth part of an inch, 

 when seen at a certain distance, and yet every part was 

 distinctly visible. What then might be the dimensions 

 of the picture of a fixed star on the same organ ? 



Mr. Roget in his " Animal and Vegetable Physiology," 

 speaking of this organ, says, " few spectacles are more 

 calculated to raise our admiration than this delicate pic- 

 ture, which nature has, with such exquisite art, and with 

 the finest touches of her pencil, spread over the smooth 

 canvass of this subtle nerve ; a picture, which" though 

 scarcely occupying a space of half an inch in diameter, 

 contains the delineation of a boundless scene of earth 

 and sky, full of all kinds of objects, some at rest, and 

 others in motion, yet all accurately represented, as to 

 their forms, colors and positions, and followed in all their 

 changes, without the least interference, irregularity, 

 or confusion. Every one of those countless and stu- 

 pendous orbs of fire, whose light, after travelling im- 

 measurable regions of space, at length reaches our eye, 

 is collected on its narrow curtain into a luminous focus 

 of inconceivable minuteness ; and yet this almost infi- 

 nitesimal point shall be sufficient to convey to the mind, 

 through the medium of the optic nerve, and brain, a 

 knowledge of the existence and position of a far distant 

 luminary, from which that light has emanated. How 

 infinitely surpassing all the limits of our conception must 

 be the intelligence, and power of that Being, who plan- 

 ned and executed an instrument comprising, within 

 such limited dimensions, such vast powers as the eye, of 

 which the perceptions comprehend alike the nearest, 

 and most distant objects, and take cognizance at once of 

 the most minute portions of matter, and of bodies of the 

 largest magnitude ! Bridgewater Treatise, vol. 2. p. 476. 



