(842)
Another Extract
Eustachio Divini hath made a Microscope of a new Invention, wherein instead of an Eye-glass convex on both sides, there are two plano-convex Glasses, which are so placed, as to touch one another in the middle of their convex surface. This Instrument, of which Hon. Fabri treats largely in his Opticks (viz, Prop. 46.) hath this peculiar, that it shews the Objects flat and not crooked, and although it takes in much, yet nevertheless magnifieth extraordinarily.
It is almost 1612 inches high, and adjusted at 4 different lengths, In the first, which is the least, it shews lines 41 times bigger than they appear to the naked Eye: In the second, 90 times: In the third, 111 times: and in the fourth 143 times. Whence one may easily calculate, how much it augments surfaces and solidities.
The Diameter of the Field it discovers, or the subtense of the visual angle, measured upon the Object-plate, in the first length is of 8 inches and 7 lines: in the second, of 12 inches and 4 lines: in the third, of 13 inches: an in the fourth, of a little more than 16 inches.
As they viewed with this Microscope the little grains of sand searced, they perceived an Animal with many feet, its back white and scaly, but less than any of those hitherto observed. For, although the Microscope shewed every grain of sand as big as an ordinary Nut, yet this Animal appeared no bigger than one of those grains of sand seen without a Microscope. Whence may be concluded its smallness, which occasion'd one of the beholders to give it the name of the Atome of Animals.
