Microscopical Essays, 



^5 



in fome fubje&s three or four different forts are obfervable, few 

 or none being fimple and homogeneous. 



When the configurations are fully formed, and all the water 

 evaporated, m oft kinds of them are ibon deilroyed again by the 

 moifture or aftion of the air upon them ; their points and angles 

 lofe their {fiarpnefs, become uneven and defaced, and moulder as 

 it were away; but fome few are permanent, and by being in- 

 clofed between glaffes, they may be preferved months or even 

 years. 



It happens oftentimes that a drop of a faline folution can 

 hardly be fpread on the hip of glafs, by reafon of the glafs's 

 fmoothnefs, but breaks into little globules, as it would do were 

 the furface greafy : the way to prevent this is, by rubbing the 

 broken drop with your finger over the glafs, fo as to leave the 

 glafs fmeared with it ; on which fmeared place, when dry, ano- 

 ther drop of the folution may be fpread very eafily in what form 

 one pleafes. 



It fometimes happens, that when a heated drop is placed 

 properly for examination, the obferver finds he can diftinguifb 

 % nothing ; which is owing to faline fleams that rife from the drop 

 cover, and obfcure the object glafs, and therefore mud imme- 

 diately be wiped away with a foft cloth' or leather. 



In all examinations by the microfcope of faline folutions, even 

 though made in the day-time, you mull life a candle; for the 

 configurations being exceedingly tranfparent, are rendered much 

 more diflinguifhable by the brown light a candle affords, than by 



