222 Dr Brewster on tht reflection and decomposition of 



Image at the Surface of Prism A. 

 Oil of Spearmint, — Very faint colours. 

 Heat brings out three good orders. 

 First limit at about 77°. 

 Oil of Lemons. — Threefine orders. First 

 limit at 74°. Heat destroys the first 

 order. 

 Oil of Dill Seed. — Two poor orders of 

 colours. First limit at 73°. Heat im- 

 proves them. 

 Oil of Peppermint. — Two good orders. 

 First limit 73°. Heat destroys the 

 first order. 

 Oil of Rapeseed. — Two very faint or- 

 ders. First limit at QB° when im- 

 proved by heat. 

 Naphtha from Persia. — Three very 



good orders. 

 Oil of Bergamot. — Three very fine or- 

 ders. First limit at 73°. Heat spoils 

 first order. 

 Oil of Beech Nut. — Three excellent or- 

 ders, and well defined. First limit 

 at 73°. Heat spoils first order. 

 Spermaceti Oil. — Two tolerable orders. 

 First red and blue bad, second red 

 and blue good. First limit at 73°. 

 Oj^ of Olives. — Three good orders. 



First limit at 73°. 

 Grass Oil. — Three good orders. First 



limit at 73°. 

 Oil of Rosemary. — Two good orders 



and more. First limit at 73°. 

 Oil of Poppy. — Three excellent orders. 

 First limit at 73°. Heat injures the 

 colours. 

 Oil of Lavender, — Three good orders. 

 First red and first blue very fine. 

 First limit at 74°. 



3 



Image at the 

 Surface of Prism B. 

 Yellowish at great 

 incidences. 



Yellowish white. 



Yellowish white. 



Yellowish white. 



Bluish gray. 

 White. 



Yellowish white. 



Yellowish white. 



Yellowish white. 

 Whitish yellow. 

 Grayish white. 

 Whitish yellow. 



Yellowish white. 



Yellowish white. 



