P L A T E IL 9 



withftanding which, this Ihell is To tranfparent that the whole motion 

 of the inteflines is very vifible by a good magnifier. 



It muft be granted that, but for the microfcope, the wonders of 

 the minute creation would be to us entirely unknown, our ideas could 

 never fuppofe the exiftence of thofe animated forms which occupy 

 the immeafurable fpace betvi^een an apparent atom and nothing. The 

 myriads of animations, thoufands of times fmaller than a mite, muft 

 evade our cognizance, and be an a£lual convi6lion of their non* 

 exiftence. 



But with all the utility that the microfcope can boaft, no Inftru- 

 ment is fo likely to millead the moft accurate obferver, particularly 

 if not in the habit of ufmg it ; the variations of light, the powers of 

 magnification, or the damage the glaffes may meet with by accident, 

 fuch as requires every one to examine with the greateft care ; one 

 degree of light may bring an object to view, whilft another may en- 

 tirely blend it with the fluid it exifts in j or one glafs may difcovef 

 fpines on an obje6t, another glafs might have reprefented perfectly 

 fmooth ; it is therefore neceflary to begin with a fmall power, in pro- 

 portion to the fize of the objeft, and to proceed to deeper mag- 

 nifiers after, 



There is fome diiFerence in our figure and thofe either of Barbut^ or 

 of Bakery which appears chiefly from our ufing a fingle lens nearly 

 of the deepeft power convenient to ufe. Our glafl'es were the 20th 

 and 30th of an inch focus. 



We very attentively examined the eyes, and found, not one, but 

 two, placed near each other, on a fcale or plate of a black colour ; 

 hence arifes the appearance of a fingle eye by a fmall magnifying 

 power. 



The tail prefents a forked appearance by a deep power, and the 

 eggs are contained in two bags, one on each fide the tail. The co- 

 lour varies probably in proportion to the nature of its food, to pale 

 green, more or lefs of a red, or of a grey brown colour. 



Fig. 



