THE CHRISTIAN PHILOSOPHER. 



and so numerous traces of Divine Beneficence 

 we may reasonably conclude, that scenes of Di 

 vine Wisdom and Goodness, far more glorious 

 ind transporting, must be displayed in those 

 worlds where moral evil has never shed its ma 

 lign influence, and where the inhabitants supe 

 rior to disease and death bask for ever in the 

 regions of immortality. And, therefore, however 

 admirable the displays of Divine Wisdom may 

 appear in the sublunary scene around us, they 

 must be considered as inferior to those which are 

 exhibited in many other provinces of Jehovah s 

 empire, in so far as they are blended with those 

 physical derangements which indicate his dis 

 pleasure against the sins of men. 



Were we now to direct our attention to the 

 mechanism of animated beings, and to consider 

 the numberless contrivances and adaptations in 

 their organical structure and functions, a thou 

 sand instances of exquisite wisdom and design, 

 still more striking and admirable, would crowd 

 upon our view. For, although the general fabric 

 of the world, and the immense variety of objects 

 it contains, are evident proofs of a Wise and In 

 telligent Contriver, yet it is chiefly in the minute 

 and delicate contrivances of organical structures, 

 their adaptation to the purposes of life, motion, 

 and enjoyment, and their relation and correspon 

 dence to the surrounding elements, that the con 

 summate skill of the Great Architect of nature 

 is most strikingly perceived. But as it forms no 

 part of my present plan to enter on so extensive 

 a field of illustration, on which volumes might be 

 written, I shall content myself with merely sta 

 ting an example or two. My first example shall 

 be taken from 



The Structure of the Human Eye. 



The eye is one of the nicest pieces of mecha 

 nism which the human understanding can contem 

 plate ; but as it requires a knowledge of its ana 

 tomical structure, and of the principles of optics, 

 to enable us to appreciate its admirable functions, 

 I shall confine myself to a few general descrip 

 tions and remarks. 



The eye is nearly of a globular form. It con 

 sists chiefly of three coats, and three humours. 

 The first or outer coat, is termed sdcrotica ; it 

 is every where white and opaque, and is joined 

 at its anterior edge to another which has more 

 convexity than any other part of the globe of ihe 

 eye. and, being exceedingly transparent, is call 

 ed the cornea. These two parts are perfectly 

 different in their structure, and are supposed, 

 fay some anatomists, to be as distinct from each 

 other as the glass of a watch is from the case into 

 which it is fix*d. Next within this coat is that 

 called the choroides, on account of its being fur 

 nished with a great nun.uer of vessels. It serves, 

 fts it were, for a ining to th -&amp;gt;ther, and is joined 



with that part of the eye termed irw. The ini 

 is an opaque membrane like the choroides, but 

 ofdifferent colours in different eyes, as gray, black, 

 or hazel. It is composed of two sets of muscular 

 fibres, the one of a circular form, which contracts 

 the hole in the middle, called the pupil, when the 

 light is too strong for the eye ; and the other, of 

 radial fibres, tends every where from the circum 

 ference of the iris towards the middle of the pupil; 

 which fibres, by their contractions, dilate and 

 enlarge the pupil, when the light is we^k, in or 

 der to let in more of its rays. The third coat is 

 called the retina, upon which are painted the 

 images of all visible objects, by the rays of light 

 which flow from them. It spreads like net-work 

 all over the inside of the choroides, and is no 

 thing more than a fine expansion of ,ie optic 

 nerve ; by which nerve the impressions of visi 

 ble objects are conveyed to the brain. 



The inside of the globe of the eye, within these 

 tunics or coats, is filled with three humours, called 

 the aqueous, the crystalline, and the vitreous. 

 The aqueous humour lies at the fore part of the 

 eye, and occupies all the space between the crys 

 talline and the prominent cornea. It has the same 

 specific gravity and refractive power as water, and 

 seems chiefly of use to prevent the crystalline 

 from being easily bruised by rubbing, or by a blow 

 and perhaps it serves for the crystalline humour 

 to move forward in, while we view near objects, 

 and backward for remoter objects; without 

 which, or some other mechanism effecting the 

 same purpose, we could not, according to the 

 laws of optics, perceive objects distinctly, wnen 

 placed at different distances. Behind the aque 

 ous lies the crystalline humour, which is shaped 

 like a double convex glass, and is a little more 

 convex on the back than on the fore part. This 

 humour is transparent like crystal, is nearly of the 

 consistence of hard jelly, and converges the rays 

 which pass through it, from visible objects, to its 

 focus at the bottom or back part of the eye. 

 The vitreous humour lies behind the crystalline, 

 and fills up the greatest part of the orb of the eye, 

 giving it a globular shape. It is nearly of the con 

 sistence of the white of an egg, and very trans 

 parent ; its fore part is concave, for the crystal 

 line humour to lodge in, and its back part being 

 convex, the retina is spread over it. It serves 

 as a medium to keep, the crystalline humour and 

 the retina at due distance. From what has now 

 been stated, it is obvious, that the images of 

 external objects are depicted in the retina, in an 

 inverted position, in the same manner as the 

 images formed by a common convex lens ; but 

 how the mind, in this case, perceives objects 

 erect, is a question, about which the learned have 

 divided in their opinions.* 



An idea of the relative positions of the coattvtA 

 humours described above, may be obtained by 

 simple inspection of the Plate, Fig. 6. Fig. 6, re 

 presents a front view of the human eye, as t ap- 



