Micrographia, by Robert Hooke

Observ. xlvi. Of the white featherwing'd Moth or Tinea Argentea.

This white long wing'd Moth, which is delineated in the 30. Scheme; Schem. 30. afforded a lovely object both to the naked Eye, and through a Microscope: to the Eye it appear'd a small Milk white Fly with four white Wings, the two formost somewhat longer then the two hindermost, and the two shorter about half an Inch long, each of which four Wings seem'd to consist of two small long Feathers, very curiously tufted, or haired on each side, with purely white, and exceedingly fine and small Haires, proportion'd to the stalks or stems, out of which they grew, much like the tufts of a long wing-feather of some Bird, and their stalks or stems were, like those, bended backwards and downwards, as may be plainly seen by the draughts of them in the Figure.

scheme30

Observing one of these in my Microscope, I found, in the first place, that all the Body, Legs, Horns and the Stalks of the Wings, were covered over with various kinds of curious white Feathers, which did, with handling or touching, easily rubb off and fly about, in so much that looking on my Fingers, with which I had handled this Moth, and perceiving on them little white specks, I found by my Microscope, that they were several of the small Feathers of this little creature, that stuck up and down in the rugosities of my Skin.

Next, I found that underneath these Feathers, the pretty Insect was covered all over with a crusted Shell, like other of those Animals, but with one much thinner and tenderer.

Thirdly, I found, as in Birds also is notable, it had differing and appropriate kinds of Feathers, that covered several parts of its body.

Fourthly, surveying the parts of its body, with a more accurate and better Magnifying Microscope, I found that the tufts or haires of its Wings were nothing else but a congeries, or thick set cluster of small vimina or twiggs, resembling a small twigg of Birch, stript or whitned, with which Brushes are usually made, to beat out or brush off the dust from Cloth and Hangings. Every one of the twiggs or branches that composed the Brush of the Feathers, appeared in this bigger Magnifying Glass (of which EF which represents ½4 part of an Inch, is the scale, as G is of the lesser, which is only 1/3) like the figure D. The Feathers also that covered a part of his Body, and were interspersed among the brush of his Wings, I found, in the bigger Magnifying Glass, of the shape A, consisting of a stalk or stem in the middle, and a seeming tuftedness or brushy part on each side. The Feathers that cover'd most part of his Body and the stalk of his wings, were, in the same Microscope, much of the figure B, appearing of the shape of a small Feather, and seemed tufted: those which covered the Horns and small parts of the Leggs, through the same Microscope, appear'd of the shape C. Whether the tufts of any or all of these small Feathers, consisted of such component particles as the Feathers of Birds, I much doubt, because I find that Nature does not alwaies keep, or operate after the same method, in smaller and bigger creatures. And of this, we have particular Instances in the Wings of several creatures. For whereas, in Birds of all kinds, it composes each of the Feathers of which its Wing consists, of such an exceeding curious and most admirable and stupendious texture, as I else where shew, in the Observations on a Feather; we find it to alter its method quite, in the fabrick of the Wings of these minute creatures, composing some of thin extended membranes or skins, such as the Wings of Dragon-flys; in others, those skins are all over-grown, or pretty thick bestuck, with short brisles, as in Flesh-flies; in others, those filmes are covered, both on the upper and under side, with small Feathers, plac'd almost like the tyles on a House, and are curiously rang'd and adorn'd with most lively colours, as is observable in Butter-flies, and several kinds of Moths; In others, instead of their films, Nature has provided nothing, but a matter of half a score stalks (if I well remember the number; for I have not lately met with any of these flys, and did not, when I first observ'd them, take sufficient notice of divers particulars) and each of these stalks, with a few single branchings on each side, resembling much the branched back-bone of a Herring or the like Fish, or a thin hair'd Peacocks feather, the top or the eye being broken off. With a few of these on either side (which it was able to shut up or expand at pleasure, much like a Fann, or rather like the posture of the feathers in a wing, whichly all one under another, when shut, and by the side of each other, when expanded) this pretty little grey Moth (for such was the creature I observ'd, thus wing'd) could very nimbly, and as it seem'd very easily move its corpuscle, through the Air, from place to place. Other Insects have their wings cas'd, or cover'd over, with certain hollow shells, shap'd almost like those hollow Trayes, in which Butchers carry meat, whose hollow sides being turn'd downwards, do not only secure their folded wings from injury of the earth, in which most of those creatures reside, but whilst they fly, serves as a help to sustain and bear them up. And these are observable in Scarabees and a multitude of other terrestrial crustaceous Insects; in which we may yet further observe a particular providence of Nature.

Now in all these kinds of wings, we observe this particular, as a thing most worthy remark; that where ever a wing consists of discontinued parts, the Pores or interstitia between those parts are very seldom, either much bigger, or much smaller, then these which we here find between the particles of these brushes, so that it should seem to intimate, that the parts of the Air are such, that they will not easily or readily, if at all, pass through these Pores, so that they seem to be strainers fine enough to hinder the particles of the Air (whether hinder'd by their bulk, or by their agitation, circulation, rotation or undulation, I shall not here determine) from getting through them, and, by that means, serve the Animal as well, if not better, then if they were little films. I say, if not better, because I have observ'd that all those creatures, that have film'd wings, move them aboundantly quicker and more strongly, such as all kind of Flies and Scarabees and Batts, then such as have their wings covered with feathers, as Butter-flies and Birds, or twiggs, as Moths, which have each of them a much slower motion of their wings; That little ruggedness perhaps of their wings helping them somewhat, by taking better hold of the parts of the Air, or not suffering them so easily to pass by, any other way then one.

But what ever be the reason of it, 'tis most evident, that the smooth wing'd Insects, have the strongest Muscles or movent parts of their wings, and the other much weaker; and this very Insect, we are now describing, had a very small thorax or middle part of his body, if compar'd to the length and number of his wings; which therefore, as he mov'd them very slowly, so must he move them very weakly. And this last propriety do we find somewhat observ'd also in bigger kind of Flying creatures, Birds; so that we see that the Wisdom and Providence of the All-wise Creator, is not less shewn in these small despicable creatures, Flies and Moths, which we have branded with a name of ignominy, calling them Vermine, then in those greater and more remakable animate bodies, Birds.

I cannot here stand to add any thing about the nature of flying, though, perhaps, on another occasion, I may say something on that subject, it being such as may deserve a much more accurate examination and scrutiny then it has hitherto met with; For to me there seems nothing wanting to make a man able to fly, but what may be easily enough supply'd from the Mechanicks hitherto known, save onely the want of strength, which the Muscles of a man seem utterly uncapable of, by reason of their smalness and texture, but how even strength also may be mechanically made, and an artificial Muscle so contriv d, that thereby a man shall be able to exert what strength he pleases, and to regulate it also to his own mind, I may elsewhere endeavour to manifest.

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