P0LAR1 ZATION-OB JECTS. 



773 



This property consists in the exhibition of different colours by 

 these crystals, according to the direction in which the light is 

 transmitted through them ; a crystal of Chloride of Platinum, for 

 example, appearing of a deep red when the light passes along its 

 axis, and of a vivid green when the light is transmitted in the 

 opposite direction, with various intermediate shades. It is only 

 possessed by Doubly-Refracting substances ; and it depends on 

 the absorption of some of the coloured rays of the light which is 

 polarized during its passage through the crystal, so that the two 

 pencils formed by double refraction become differently coloured, — 

 the degree of difference being regulated by the inclination of the 

 incident ray to the axis of double refraction. 



Acetate of Copper, d 



of Manganese 



of Soda 



'— of Zinc 



Alum 



Arseniate of Potass 



Asparagine 



Aspartic Acid 



Bicarbonate of Potass 



Bichromate of Potass 



Bichloride of Mercury 



Binoxalate of Chromium and 



Potass 

 Bitartrate of Ammonia 



of Lime 



of Potass 



Boracic acid 

 Borate of Ammonia 



of Soda (borax) 



Carbonate of Lime (from urine of 



horse) 

 Carbonate of Potass 



■ — of Soda 



Chlorate of Potass 

 Chloride of Barium 



of Cobalt 



of Copper and Ammonia 



of Palladium, d 



of Sodium 



Cholesterine 

 Chromate of Potass 

 Cinchonoidine 

 Citric Acid 

 Cyanide of Mercury 

 Hippuric Acid 

 Hypermanganate of Potass 

 Iodide of Potassium 



of Quinine 



Mannite 



Margarine 



Murexide 



Muriate of Ammonia 



Nitrate of Ammonia 



of Bai-ytes 



of Bismuth 



of Copper 



of Potass 



Nitrate of Soda 



of Strontian 



of Uranium 



Oxalic acid 



Oxalate of Ammonia 



of Chromium 



of Chromium and Ammo- 

 nia, d 



of Chromium and Potass, (/ 



of Lime 



of Potass 



of Soda 



Oxalurate of Ammonia 

 Phosphate of Ammonia 



Ammoniaco-Magnesian 



(triple, of urine) 



of Lead, d 



of Soda 



Platino-chloride of Thallium 

 Platino-cyanide of Ammonia, d 

 Prussiate of Potass (red) 



Ditto ditto (yellow) 

 Quinidine 

 Salicine 

 Saliginine 

 Santonine 

 Stearine 

 Sugar 



Sulphate of Ammonia 

 of Cadmium 



of Copper 



of Copper and Ammonia 



of Copper and Magnesia 



of Copper and Potass 



of Iron 



of Iron and Cobal 



of Magnesia 



■ of Nickel 



of Potassa 



of Soda 



of Zinc 



Tartaric Acid 

 Tartrate of Soda 

 Uric Acid 

 Urate of Ammonia 

 of Soda 



