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Hooke, Robert, 1635-1703 / Micrographia: or some physiological descriptions of minute bodies made by magnifying glasses : with observations and inquiries thereupon
(MDCLXVII [1667])

Observ. XXXIX. Of the eyes and head of a grey drone-fly, and of several other creatures,   pp. 175-180


Page 175


M1ICROGTAPH I A.*
Obfcrv. XX X I X. Of the Eyes and -lead of a Grey drone-VIya
   and offeveral other creatures.
I took a large grey Drone-l y, that had a large head, but a fmall and
  flender body in proportion t o ir,and Cutting off its head, I fix'd it
with
theforepart or face upwards ul-on my Objct Hlate (this I made choice
of rather then the head ofa great blue Fly,becaufe my enquiry being now
about the eyes,I found this Fly to have. firft the biggeft clufters of eyes
in proportion to his head, ofany Imiall kind of Fly that I have yet feen,
it
being fomewhat inclining towards the make of the large Dragon-Flies.
Next, becaufe there is a greater variety in the knobs or balls of each
clufterthen is of any fmall Fly) Then examining it according to my ufual
manner, by varying the degrees of light, and altering its portion to each
kinde of light, I drew that reprefentation of it which is delineated in
the 24. scheme, and found thefe things to be as plain and evident, as
notable and pleaflnt.
  Firfi, that the'greateft part ofthe face,nay,of tle head,was nothing elfe
but two large and protuberant bunches,orpromri nentparts,A B C D E Athe
furface of each of which was all cover'd over, or fhap'd into a multitude
of fimall Hemifpheres,plac'd in a triagonal order,that being the clofeft
and
moft compaded, and in that order, rang'd over the whole furface of the
eye in very lovely rows between each of which, as is neceffiry, were left
long and regular trenches, the bottoms of every of which, wetre perfefly
intire and not at all perforated or drill'd through, which I mnoft certainly
was afluired of, by the regularly reHeted Image of certain Obje&s which
I mov'd to and fro between the head and the light. And by examining
the Cornea or outward &kin, after I had fiript it off from the feveral
fub"
ftances that lay within it,and by looking both upon the infide and againft
the light.
  Next, that of thofe multitudes of Hemi4hcres, there were obfervablk
two degrees of bignefs, the half of them that were lowermoftand look'd
toward the ground or their own leggs, namely, CD E, C D E being a
pretty deal fmaller then the other, namely, A B C E, A B CGE, that: look''d.
upward, and fide-waysor foreright,and backward, which varietyJ have
not found in any other finall Fly.
  Thirdly, that every one of there Hemifpherex,as they feem'd to be pret-
ty neer the true fhape of a HerniJfhere, fo was the furface exceeding
fmooth and regular, rcfleffing as exa~t, regular, and perfet an Image of
any Objed from the furface of them, as a fmall Ball of Quicks-ilver of
that bignefs would do, but nothing neer fo vivid, the reflefion from titefe
being very languid, much like the reflection from the outfide of Water,
Glafs, Cryflal, Aic. In fo much that in each of thefe Hemifpheres, I have
been able to difcover a Land-fcape of thofe things which lay before my
                                                          window,


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