NATURAL THEOLOGY. 39 



being its nature, in order to fit it up for its office, it is 

 connected by a tendon or thread, with a muscle 

 in the back part of the eye : this tendon or thread, 

 though strong, is so fine as not to obstruct the sight, 

 even when it passes across it ; and the muscle itself, 

 being placed in the hack part of the eye, derives 

 from its situation the advantage, not only of being 

 secure, but of being out of the way ; which it would 

 hardly have been in any position that could be as- 

 signed to it in the anterior part of the orb, where 

 its function lies. When the muscle behind the 

 eye contracts, the membrane, by means of the 

 communicating thread, is instantly drawn over the 

 fore-part of it. When the muscular contraction 

 (which is a positive and most probably a volun- 

 tary effort,) ceases to be exerted, the elasticity 

 alone of the membrane brings it back again to its 

 position.* Does not this, if anything can do it, be- 

 speak an artist, master of his work, acquainted with 

 his materials ? " Of a thousand other things," say 

 the French Academicians, "we perceive not the 

 contrivance, because we understand them only by 

 their effects, of which we know not the causes : 

 but we here treat of a m.achine, all the parts 

 whereof are visible, and which need only be looked 

 upon to discover the reasons of its motion and 

 action, f *' 



* Phil. Trans. 1796. 



t Memoirs for a Natural History of Animals, by the Royai 

 Academy of Sciences at Paris, done into English by order of the 

 E,ojal Society, 1701, p. 249. — Foley . 



