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PRACTICAL MICROSCOPY. 



It is not enough to mount slides of salicine and other 

 crystalline forms for the production of rainbow colours, 

 and therefore the author imagines he cannot do better 

 than give a list of the principal works which may be con- 

 sulted: * Lectures on Polarised Light,' by T. P., Long- 

 man and Co., 1843; 'Polarisation of Light/ by William 

 Spottiswoode, Nature Series, 1874 ; 'A Familiar Intro- 

 duction to the Study of Polarised Light/ by C. Woodward, 

 Van Voorst, 1861 ; 'Mineralogie Micrographique/ MM. 

 Fouqud and LeVy, published by the French Minister of 

 Public Works, and is a most valuable work to all concerned 

 in microscopic mineralogy. 



To conclude this chapter a list is given of many polaris- 

 ing objects : 



ANIMAL SUBSTANCES. 



Palate of limpet. 



periwinkle. 



whelk. 

 Embryo oysters. 

 Human hair. 

 Raw silk. 



Human corns. 

 Horn of rhinoceros. 



antelope. 

 Skin of rhinoceros. 

 Alpaca wool. 

 Porcupine quill.- 



VEGETABLE SUBSTANCES. 



Starch from tous les mois. 

 potato. 



,, arrowroot. 

 maize. 

 Cotton fibres. 



Plant raphides. 



Seed of Eccremocarpus. 



Cuticle of Correa cardinalis. 



Fern scales. 



Jute fibres. 



CHEMICAL CRYSTALS. 



Salicine. 



Quinine. 



Chlorate of potash. 



Cane sugar. 



Brownian motion in fluids. 



Oxalic acid. 



Sulphate of copper. 



Asparagine. 

 Quinidine. 

 Strychnine. 

 Tartaric acid. 

 Citric acid. 

 Sulphate of lime. 

 Chloride of barium. 



