only of being fecure, but of being out of the way; which it would hardly have been in any pofition that could be affigned 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 inftantly drawn over the forepart of it. When the mufcular contraction (which is a positive, and, most probably, a voluntary effort,) ceases to be exerted, the elasticity alone of the membrane brings it back again to its position*. Does not this, if any thing can do it, befpeak an artist, mafter 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 the effects, of which we know not the caufes but we here treat of a machine, all the parts whereof are visible; and which need only be looked upon to discover the reasons of its motion and action t."

Phil. Tranf. 1796.

+ Memoirs for a Natural Hiftory of Animals by the Royal Academy of Sciences at Paris, done into English by Order of the Royal Society, 1701, p. 249.

In the configuration of the muscle, which, though placed behind the eye, draws the nictitating membrane over the eye, there is, what the authors, just now quoted, deservedly call a marvellous mechanifm. I fuppose this structure to be found in other animals; but, in the Memoirs from which this account is taken, it is anatomically demonftrated only in the caffowary. The mufcle is paffed through a loop formed by another mufcle; and is there inflected, as if it were round a pulley. This is a peculiarity; and obferve the advantage of it. A fingle mufcle with a straight tendon, which is the common mufcular form, would have been fufficient, if it had had power to draw far enough. But the contraction, neceffary to draw the membrane over the whole eye, required a longer mufcle than could lie ftraight at the bottom of the eye. Therefore, in order to have a greater length in a less compass, the cord of the main mufcle makes an angle. This, fo far, antwered the end; but, ftill further, it makes an angle, not round a fixed pivot, but round a loop formed by another mufcle; which fecond mufcle, whenever it contracts, of courfe twitches the first muscle

at

at the point of inflection, and thereby assists the action defigned by both.

One queftion may poffibly have dwelt in the reader's mind during the perufal of these obfervations, namely, Why fhould not the Deity have given to the animal the faculty of vifion at once? Why this circuitous percep tion; the miniftry of fo many means? an element provided for the purpofe; reflected from opaque fubstances, refracted through transparent ones; and both according to precife laws: then, a complex organ, an intricate and artificial apparatus, in order, by the operation of this element, and in conformity with the reftrictions of thefe laws, to produce an image upon a membrane communicati g with the brain? Wherefore all this? Why make the difficulty in order only to furmount it? If to perceive objects by fome other mode than that of touch, or objects which lay out of the reach of that fenfe, were the thing purpofed, could not a fimple volition of the Creator have communicated the capacity? Why resort to contrivance, where power is omnipotent? Contrivance, by its very definition and nature,

is the refuge of imperfection. To have recourfe to expedients, implies difficulty, impediment, reftraint, defect of power. This queftion belongs to the other fenfes, as well as to fight; to the general functions of animal life, as nutrition, fecretion, refpiration; to the œconomy of vegetables; and indeed to almoft all the operations of nature. The question therefore is of very wide extent; and, amongst other answers, which may be given to it, befide reafons of which probably we are ignorant, one answer is this. It is only by the display of contrivance, that the existence, the agency, the wisdom of the Deity, could be teftified to his rational creatures. This is the fcale by which we afcend to all the knowledge of our Creator which we poffefs, fo far as it depends upon the phænomena, or the works of nature. Take away this, and you take away from us every subject of obfervation, and ground of reafoning; I mean as our rational faculties are formed at prefent. Whatever is done, God could have done, without the intervention of inftruments or means: but it is in the conftruct on of inftruments, in the choice and adaptation of means, that a creative intelligence is fen. It is this which conftitutes the order and

and beauty of the univerfe. God, therefore, has been pleased to prefcribe limits to his own power, and to work his ends within those limits. The general laws of matter have perhaps the nature of thefe limits; its inertia, its reaction; the laws which govern the communication of motion, the refraction and reflection of light, the conftitution of fluids non-elaftic and elastic, the transmission of sound through the latter; the laws of magnetifm, of electricity; and probably others yet undiscovered. These are general laws; and when a particular purpofe is to be effected, it is not by making a new law, nor by the suspension of the old ones, nor by making them wind and bend and yield to the occafion (for nature with great fteadinefs adheres to, and fupports them), but it is, as we have seen in the eye, by the interpofition of an apparatus correfponding with these laws, and fuited to the exigency which results from them, that the purpofe is at length attained. As we have faid, therefore, God prescribes limits to his power, that he may let in the exercise, and thereby exhibit demonftrations. of his wifdom. For then, i. e. fuch laws and limitations being laid down, it is as though one Being should have fixed certain rules;

and,