28 OBJECTS, ADVANTAGES, AND 



long-pointed pin, but thinner and thinner, longer and longer, till it is 

 quite a straight line, and has no perceptible breadth or thickness at all. 

 If we would dispose of the given quantity of matter so that it shall 

 have a certain length only, say a foot, and a certain breadth at the 

 thickest part, say three inches, and move through the air or water with 

 the smallest possible resistance which a body of those dimensions can 

 meet, then we must form it into a figure of a peculiar kind, called the 

 Solid of least resistance, because of all the shapes that can be given to 

 the body, its length and breadth remaining the same, this is the one 

 which will make it move with the least resistance through the air, or 

 water, or other fluid. A very difficult chain of mathematical reasoning, 

 by means of the highest branches of algebra, leads to a knowledge of 

 the curve, which by revolving on its axis makes a solid of this shape, in 

 the same way that a circle by so revolving makes a sphere or globe ; and 

 the curve certainly resembles closely the face or head part of a fish. Na- 

 ture, therefore, (by which we always mean the Divine Author of nature,) 

 has fashioned these fishes so, that, according to mathematical principles, 

 they swim the most easily through the element they live and move in. 



Suppose upon the face part of one of these fishes a small insect were 

 bred, endowed with faculties sufficient to reason upon its condition, and 

 upon the motion of the fish it belonged to, but never to have discovered 

 the whole size and shape of the face part, it would certainly complain 

 of the form as clumsy, and fancy that it could have made the fish so as to 

 move with less resistance. Yet if the whole shape were disclosed to it, 

 and it could discover the principle on which that shape was preferred, 

 it would at once perceive, not only that what had seemed clumsy was 

 skilfully contrived, but that if any other shape whatever had been taken, 

 there would have been an error committed ; nay, that there must of 

 necessity have been an error ; and that the very best possible arrange- 

 ment had been adopted. So it may be with man in the Universe, where, 

 seeing only a part of the great system, he fancies there is evil ; and 

 yet, if he were permitted to survey the whole, what had seemed im- 

 perfect might appear to be necessary for the general perfection, inso- 

 much that any other arrangement, even of that seemingly imperfect 

 part, must needs have rendered the whole less perfect. The common 

 objection is, that what seems evil might have been avoided ; but in the 

 case of the fish's shape it could not have been avoided. 



It is found by optical inquiries, that the rays or particles of light, in 

 passing through transparent substances of a certain form, are bent to 

 a point where they make an image or picture of the shining bodies 

 they come from, or of the dark bodies they are reflected from. Thus, 

 if a pair of spectacles be held between a candle and the wall, they 

 make two images of the candle upon it ; and if they be held between the 

 window and a sheet of paper when the sun is shining, they will make a 

 picture on the paper of the houses, trees, fields, sky, and clouds. The 

 eye is found to be composed of several natural magnifiers which make a 

 picture on a membrane at the back of it, and from this membrane there 

 goes a nerve to the brain, conveying the impression of the picture, by 

 means of which we see it. Now, white light was discovered by New- 

 ton to consist of different-coloured parts, which are differently bent in 

 passing through transparent substances, so that the lights of different 



