CHAPTER XV.

RELATIONS.

WHEN feveral different parts contribute to one effect; or, which is the fame thing, when an effect is produced by the joint action of different inftruments; the fitnefs of fuch parts or inftruments to one another, for the purpofe of producing, by their united action, the effect, is what I call relation: and whereever this is observed in the works of nature or of man, it appears to me to carry along with it decifive evidence of underftanding, intention, art. In examining, for inftance, the feveral parts of a watch, the fpring, the barrel, the chain, the fusee, the balance, the wheels of various fizes, forms, and pofitions, what is it which would take the obferver's attention, as moft plainly evincing a conftruction, directed by thought, deliberation, and contrivance? It is the fuitablenefs of thefe parts to one another, firft, in the fucceffion and order in which they act; and, fecondly, with a view

to

to the effect finally produced. Thus, referring the fpring to the wheels, he fees, in it, that which originates and upholds their motion; in the chain, that which tranfmits the motion to the fufee; in the fufee, that which communicates it to the wheels; in the conical figure of the fusee, if he refer back again to the spring, he fees that which corrects the inequality of its force. Referring the wheels to one another, he notices, first, their teeth, which would have been without ufe or meaning, if there had been only one wheel, or if the wheels had had no connection between themselves, or common bearing upon fome joint effect; fecondly, the correfpondency of their pofition, fo that the teeth of one wheel catch into the teeth of another; thirdly, the proportion obferved in the number of teeth of each wheel, which determines the rate of going. Referring the balance to the rest of the works, he faw, when he came to under, ftand its action, that which rendered their mo tions equable. Laftly, in looking upon the index and face of the watch, he saw the ufe and conclufion of the mechanifm, viz. mark ing the fucceffion of minutes and hours; but all depending upon the motions within, all

upon

upon the fyftem of intermediate actions between the spring and the pointer. What thus ftruck his attention in the feveral parts of the watch he might probably defignate by one general name of "relation:" and obferving, with respect to all the cases whatever, in which the origin and formation of a thing could be ascertained by evidence, that these relations were found in things produced by art and defign, and in no other things, he would rightly deem of them as characteristic of fuch productions. To apply the reasoning here described to the works of nature.

The animal œconomy is full; is made up of these relations.

I. There are firft, what, in one form or other, belong to all animals, the parts and powers which fucceffively act upon their food. Compare this action with the process of a manufactory. In man and quadrupeds, the aliment is, firft, broken and bruifed by mechanical inftruments of maftication, viz. fharp fpikes or hard knobs, preffing against, or rubbing upon, one another: thus ground and comminuted, it is carried by a pipe into the ftomach, where it waits to undergo a great chymical action, which we call digeftion:

when

when digefted, it is delivered through an orifice, which opens and fhuts as there is occafion, into the first intestine: there, after being mixed with certain proper ingredients, poured through a hole in the fide of the veffel, it is further diffolved: in this ftate, the milk, chyle, or part which is wanted, and which is fuited for animal nourishment, is ftrained off by the mouths of very small tubes, opening into the cavity of the inteftines: thus freed from its groffer parts, the percolated fluid is carried by a long, winding, but traceable course, into the main ftream of the old circulation; which conveys it, in its progrefs, to every part of the body. Now. I fay again, compare this with the process of a manufactory; with the making of cyder, for example, the bruifing of the apples in the mill, the fqueezing of them when fo bruifed in the prefs, the fermentation in the vat, the bestowing of the liquor thus fermented in the hog heads, the drawing off into bottles, the pouring out for ufe into the glass. Let any one shew me any difference between these two cafes, as to the point of contrivance. That which is at prefent under our confideration, the "relation"

of

of the parts fucceffively employed, is not more clear in the last cafe, than in the firft. The aptnefs of the jaws and teeth to prepare the food for the ftomach, is, at least, as manifeft, as that of the cyder-mill to crush the apples for the prefs. The concoction of the food in the ftomach is as neceffary for its future úfe, as the fermentation of the ftum in the vat is to the perfection of the liquor. The difpofal of the aliment afterwards; the action and change which it undergoes; the route which it is made to take, in order that, and until that, it arrive at its destination, is more complex indeed and intricate, but, in the midst of complication and intricacy, as evident and certain, as is the apparatus of cocks, pipes, tunnels, for transferring the cyder from one veffel to another; of barrels and bottles for preferving it till fit for ufe, or of cups and glaffes for bringing it, when wanted, to the lip of the confumer. The character of the machinery is in both cafes this, that one part answers to another part, and every part to the final

refult.

This parallel between the alimentary operation and fome of the proceffes of art, might be

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carried