Dr Goring on lieflecting Microscopes, 41 



one may see by consulting the end of that chapter of the 

 " Microscopic Illustrations," in which I have discussed the 

 [);)int : " Whether there is a best possible way of constrticting- 

 the mounting, i^c. of microscopes.''' What I really want to do 

 is, " to apply the term ' Engiscope'' to those instruments which 

 shew an image of the object under consideration (as telescopes 

 (})), instead of the object itself ^'' in order to avoid confusion. 

 The nomenclature of every science must improve as the science 

 itself does ; — we have new terms daily invented in anatomy, 

 botany, chemistry, geology, mineralogy, &c. &c., which are ex- 

 tremely indispensable to define exactly what we talk or write 

 iibout. What prodigious alterations have been made in the 

 language of chemistry, for example.^ in the last century ! in 

 another perhaps the terms even now used, may have gone out 

 of fashion. Poor microscopic science has been nearly as much 

 advanced in proportion of late as any other, and the terms I 

 am desirous of introducing into it are the following : — 



Lens or magnifiers for an unset glass, or one only framed so 

 IS to be held in the hand ; if two or three are combined, I call 

 the combination a compound magnijier, &c. 



If the said magnifier is fitted up with a stand, &c., I call it a 

 " Microscope,"" — a Single or Simple one, if the lens is single; 

 if two or three are combined, then a " Compound Microscope ; 

 if the composition is achromatic, then an " Achromatic* Mi- 

 croscope^' or a " Compound Achromatic Microscope^'' if two or 

 three achromatics are combined. I have applied the same 

 terms to the solar microscope according to the nature of the 

 construction of its optical part ; — thus, one with a single lens 

 I term a " Single or Simple Solar Microscope ,-"[if a single 

 achromatic lens is used to form the image, " a Solar Achroma- 

 tic ;'' if more than one is employed, a " Compound Solar Achro- 

 matic,'''' &c. &c. ; and if a body and eyeglasses are added 

 TO IT, then I term it a " Solar Engiscope," for distinction's 

 hike, just as in the cases already adduced; which seems to me 

 (|uite consistent. I have described a solar engiscope forming 



• I have frequently substituted the word " Aplanatic" for « Achromatic," 

 as being more expressive of the nature of a combination, in vkich there is vo 

 '.-ror, either of sphericity or rctrangibility ; aglass maybe perfectly " achro- 

 matic," i. e. free from colour, yet good for nothing, trotti spherical ftberra- 

 tion, 



