172 MuacrocRapPuHuia. 
)» as tothink all thofe things the productions of chance? Certainly, ei- 
“ther their Ratiocination muft be extremely depraved,or they did never 
attentively confider and contemplate the Works of the Al-mighty, 
—e 
Obferv. XXXVIII. Of the Struéture and motion of the Wings 
of Flies. ; 7 an wale 
of He Wings of all kinds of Infects; are, for the moft part, very 
_ =, beautifull Objeés, and afford no lefs pleafing an Objeé tothe mind 
to fpeculate upon,then to the eye to behold. This of the blue Fly,among 
the reft; ‘wants not its peculiar ornaments and contrivances 5 it grows 
out of the Thorax, or middle part of the body of a Fly, and is feateda 
little beyond the center of gravity in the body towards the head, but 
that Excentriclj iscurioufly balanc’d ; firft, by the expanded Area ofthe 
wings which lies all more backwards then the root, by the motion of 
them,whereby the center of their vibration is much more backwards to- 
wards the tail of the Fly then the root of the wing is, What the vibra- 
tive motion of the wings is; and after what manner they are moved, I 
have endeavoured by many trials to find out: And the feft manner 
oftheir motion, I endeavoured to obferve feveral of thofe kind of fall 
{pinning Flies, which will naturally fafpend themfelves, as it were; pois'd 
and fteady in one place of the air, without rifing or falling, or moving 
forwards or backwards; for by looking down on thofe, I could bya kind 
'| of faint thadow, perceive the utmoft -extremes of the vibrative ‘moti- 
on of their wings, which fhadow, whil'ft they fo endeavoured to fifpend’ 
themfelves, was not very long, but when they endeavour'd to flie for- 
wards,it was fomewhat longer ; next,I tried it,by fixing the leggs of aFly 
| upon the top ofthe ftalk of a feather, with Glew, Wax, Gc. and--then 
' making it endeavour to flie away 3 for being thereby able to view itin’ 
any pofture, I collected that the motion of the wing was after this man- 
ner. Ihe extreme limits of the vibrations were ufuially fomewhat ‘about’ 
| the length of the body diftant from one another, oftentimes fhorterjand 
fometimes alfo longer 3 that the formoft limit was ufually a liteleabove 
| the back,and the hinder fomwhat beneath the bellysbetween which two 
"limits, if one may ghefs by the found, the wing -feem’d to be mov'd for- 
wards and backwardswith an equal velocity: And ifone may (from 
fhadow or faint reprefentation the Wings aftorded, and from the eonfide- 
ration of the nature of the thing’) ghefs at. the» pofture “or manner 
of the wings moving betweeen them, it feem’d to be this The’ 10g, 
being fuppos'd placed in. the upmoft limit, feems to be put fo'that ‘the 
plain of it lies almoft horizontal, but onely the forepart does dipa jitele, 
or is fomewhat more depreft; in this pofition isthe wing vibratee 
or movd to the lower limit, being :.almoft -arrivedyat the fowet Ti- 
mit, the hinder part of. the wing ‘moving fomewhat fatter ehe® the 
. rmer, 
