LIGHT. 



133 



accompanying development of polarization properties 

 may be projected. It will be simply necessary to mag- 

 nify the object by using a lens of short focus as in the 

 former instruction for the solar microscope. The strip 

 of clear glass, holding a drop of a saturated solution 

 of the substance, the objective, and the Nicol's prism 

 being put near the focus of a condenser of twelve to 

 eighteen inches focus, that the specimen may be lighted 

 as much as possible, and also have sufficient light trans^ 

 mitted. 



±ig. 100. 



The following list of salts and other substances will 

 be found to be beautiful objects for polarized light : — 



and 



