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 NicoPs 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. 



Jfig. 1OO. 



The following list of salts and other substances will 

 be found to be beautiful objects for polarized light : 



Alum, 



Borax, 



Carbonate of Lime, 



Carbonate of Soda, 



Chloride of Barium, 



" " Copper and 



Ammonia, 



Chloride of Sodium, 

 Chlorate of Potash, 

 Citric Acid, 

 Nitrate of Bismuth, 



" " Copper, 



" Potash, 



Oxalate of Ammonia, 



Lime, 

 Oxalic Acid, 

 Picric Acid, 

 Prussiate of Potash, 

 Salicine, 



Sulphate of Copper, 

 " *< a 



Magnesia, 

 Sulphate of Iron, 

 " Soda, 

 " Zinc, 

 Sugar, 



and 



