* Microscopical Essays. 



necetTary for this purpofe : for there are many cireum fiances 

 where the images feen may be very fnnilar, though originating 

 . from fubftances totally different • it is here the penetration of the 

 obferver will be exercifed, to difcover the difference, and avoid 

 error.* 



Hence Mr. Baker f cautions us againfl forming an opinion too 

 fuddenly of any microfcopic object, and not to draw our inferen- 

 ces till after repeated experiments and examinations of the object, 

 in all lights and various pofitions ; to pafs no judgment upon 

 things extended by force, or contracted by drynefs, or in any 

 manner out of a natural ftate, without making fuitable al- 

 lowances. 



The true colour of objects cannot be properly determined 

 when viewed through the deepefl magnifiers ; for, as the pores 

 and interfaces of an object are enlarged, according to the magni- 

 fying power of the glaffes made ufe of, the component particles 

 of it's fubfiance will appear feparated many thoufand times farther 

 afunder than they do to the naked eye : it is, therefore, very 

 probable, that the reflection of the light from thefe particles will 

 be very different, and exhibit different colours. 



Some confideration is alfd neceffary in forming a judgment of 

 the motion of living creatures, or even of fluids, when feen 

 through the microfcope ; for as the moving body, and the fpace 

 wherein it moves, are magnified, the motion will alfo be increafed. 



If 



* Fontana fur les Poifons, vol. ii. p. 245. 

 + Baker's Microfcope made Eafy, p. 62^ 



