Microscopical. Essays. 505 



-and fo alternately, whereby it's progreffion is in a diagonal line, 

 or from corner to corner ; as whoever will take the trouble to 

 (hi ft the points of a pair of compares in that manner, may imme- 

 diately be fatisfied. 



All it's motions are extremely flow, and require much patience 

 and attention in the obferver. It has neither feet, nor fins, nor 

 hairs, but appears perfectly fmooth and tranfparent, with the 

 head bending one way, and the tail another, fo as to be like a 

 long Italic S; nor is any internal motion, or particularly opake 

 part, to be perceived, which may determine one to fuppofe it the 

 -flomach, or other of the inteitines. 



Thefe creatures are fo fmall, that millions of millions might be 

 contained in an inch fquare. When viewed llngly, or feparatcd 

 from one another, they are exceedingly tranfparent, and of a 

 lovely green; but, like all other tranfparent bodies, when num- 

 bers of them are brought together they become opake, and lofe 

 their green colour in proportion as the quantity increafes, till at 

 laft they appear entirely black. 



Not with (landing: the extreme minutenefs of thefe animalcula, 



a 



they feem to be fond of fociety ; for on viewing 1 for fome time 

 a parcel of them taken up at random, they will be feen to difperfe 

 themfelves in a kind of regular order. If a multitude of them are 

 put into a jar of water, they will form themfelves into a regular 

 body, and afcend flowly to the top, where, after they have re- 

 mained fome time expofed to the air, their green colour changes 

 to a beautiful Iky -blue. When they are weary of this fituation, 



3 Q lhe y 



