18 ON THE ACTION OF TRANSPARENT BODIES 
It acts less powerfully upon green light than sulphuric acid, 
phosphoric acid and water. 
69. Rosemary, Oil of. 
This oil acts less powerfully upon green light than crown-. 
glass, and a very little more powerfully than flint-glass. 
70. Rosin. 
This substance acts less powerfully upon green light than: 
crown-glass and flint-glass. The secondary spectrum with. 
flint-glass, is fully as great as that produced by flint-glass.oppo- 
sed to crown-glass. 
Rosin acts a little less powerfully upon the green rays than 
oil of cloves. 
. 71. Rue, Oil of 
This oil acts more powerfully upon the green rays than 
crown-glass, and a very little more powerfully than flint-glass.. 
72. Sage, Oil of: 
This oil acts less powerfully upon green light than either 
crown or flint glass. 
73. Sassafras, Oil of: 
This oil acts more powerfully upon green light than o#/ of: 
cassia, balsam of Tolu, and oil of anise-seeds, but less powerful- 
ly than crown and flint glass, and oil of cloves. 
74. Savine, Oil of. 
This oil acts less powerfully upon the green rays than crown-. 
glass, and perhaps a little less powerfully than flint-glass ; but 
more powerfully than oi/ of spearmint, ie 
75. Selenite. 
