WeRead Powered by ReaderPub
Physico-theology cover

Physico-theology

Chapter 75: CHAP. III.
By W. Derham
Open in WeRead

Explore more books like this:

Philosophy & EthicsReligion/Spirituality

About This Book

A series of sixteen sermons presents a physico-theological demonstration of God's existence and attributes by examining natural phenomena. The author combines natural-history observations, microscopy, and philosophical argument to infer design and divine qualities from created order, addressing objections and drawing on earlier naturalists' findings. Sermon text is interwoven with extended notes and curious observations on plants, animals, geological forms, and the mechanics of living structures. The work aims to make empirical knowledge serve theological ends by showing how observable features of nature support claims about a creator's power, wisdom, and benevolence.

CHAP. III.

Of the Eyes and Antennæ of Insects.

To this last-mention’d Guard, we may add, that farther Guard provided in the Eyes and Antennæ. The Structure of the Eye, is, in all Creatures, an admirable Piece of Mechanism; but that observable in the Eyes of Insects so peculiar, that it must needs excite our Admiration: Fenced with its own Hardness, yea, even its own accurate Vision, is a good Guard against external Injuries; and its Cornea, or outward Coat, all over beset with curious, transparent, lenticular[a] Inlets, enabling those Creatures to see, (no doubt,) very accurately every Way, without any Interval of Time or Trouble to move the Eye towards Objects.

And as for the other Part, the Antennæ, or Feelers, whatever their Use may be in cleaning the Eyes, or other such like use; they are, in all Probability, a good Guard to the Eyes and Head, in their Walk and Flight, enabling them, by the Sense of Feeling, to discover such Annoyances, which by their Proximity may perhaps escape the Reach of the Eyes and Sight[b]. Besides which, they are a curious Piece of Workmanship, and in many, a very beautiful Piece of[c] Garniture to the Body.

FOOTNOTES:

[a] The Cornea of Flies, Wasps, &c. are so common an Entertainment with the Microscope, that every body knows it is a curious Piece of Lattice-work. In which this is remarkable, that every Foramen is of a lenticular Nature; so that we see Objects through them topsey-turvey, as through so many convex Glasses: Yea, they become a small Telescope, when there is a due focal Distance between them and the Lens of the Microscope.

This lenticular Power of the Cornea, supplies, (as I imagine,) the Place of the Crystalline, if not of the vitreous Humour too, there being neither of those Humours that I could ever find, (although for Truth Sake, I confess I have not been so diligent as I might in this Enquiry;) but instead of Humours and Tunicks, I imagine that every Lens of the Cornea, hath a distinct Branch of the optick Nerve ministring to it, and rendring it as so many distinct Eyes. So that as most Animals are binocular, Spiders for the most Part octonocular, and some, (as Mr. Willughby thought, Raii Hist. Insect. p. 12.) senocular; so Flies, &c. are multocular, having as many Eyes as there are Perforations in their Cornea. By which Means, as other Creatures are oblig’d to turn their Eyes to Objects, these have some or other of their Eyes ready plac’d towards Objects, nearly all round them: Thus particularly it is in the Dragon-Fly, (Libella,) the greatest Part of whose Head is possess’d by its Eyes: Which is of excellent Use to that predatious Insect, for the ready seeing and darting at small Flies all round it, on which it preys.

[b] It is manifest, that Insects clean their Eyes with their Fore-legs, as well as Antennæ. And considering, that as they walk along, they are perpetually feeling, and searching before them, with their Feelers, or Antennæ; therefore I am apt to think, that besides wiping and cleaning the Eyes, the Uses here nam’d may be admitted. For as their Eyes are immoveable, so that no Time is requir’d for the turning their Eyes to Objects; so there is no Necessity of the Retina, or optick Nerve being brought nigher unto, or set farther off from the Cornea, (which would require Time,) as it is in other Animals: But their Cornea and optick Nerve, being always at one and the same Distance, are fitted only to see distantial Objects, but not such as are very nigh: Which Inconvenience the Feelers obviate, lest it should be prejudicial, in occasioning the Insect to run its Head against any Thing.

And that this, rather than the wiping the Eyes, is the chief Use of the Feelers, is farther manifest from the Antennæ of the Flesh-Fly, and many other Insects, which are short, and strait, and incapable of being bent unto, or extended over the Eyes: As also from others enormously long, such as those of the Capricorni, or Goat-chasers, the Cadew-Fly, and divers others, both Beetles and Flies.

[c] The lamellated Antennæ of some, the clavellated of others, the neatly articulated of others, the feather’d and divers other Forms of others, of the Scarab, Papilionaceous Gnat, and other Kinds; are surprizingly beautiful, when view’d through a Microscope. And in some, those Antennæ distinguish the Sexes: As in the Gnat-kind, all those with Tufts, Feathers, and Brush-horns, are Males; those with short, single shafted Antennæ, are Females.