Experiments on various Liquids. 259 



The sulphides of the alcohol radicals are purely negative 

 and weaker than the corresponding oxides, but much stronger 

 than the alcohols. From lower members upwards they rise 

 in electro-optic power (13). 



The hydrosuiphides are purely positive, and stronger than 

 the corresponding fatty acids. From lower members upwards 

 they rise in power (14). 



Of the compound ethers, all that have been examined are 

 clearly positive ; and they include examples of the formates, 

 acetates, butyrates, valerates, benzoates, nitrates, and nitrites. 

 The optical effects are pure in the butyrates, but more or less 

 disturbed in the others, impure in the acetates, very impure 

 in the formates (15-21). 



The following table contains a few additional bodies which 

 are found to be electro-optically active. The optical effects 

 are neither impure nor very weak, except in the cases that are 

 so marked. The positive and the negative dielectrics appear 

 always in the left-hand and right-hand columns respectively. 



Compounds of C, H, (22, 23). 



Acetone (wk). Aldehyde (wk). 



Valeral. Palm-oil. 



(Enanthol. Cacao butter. 



Benzoyl hydride. Lard. 



Methyl salicylate Tallow. 



Ethene monacetate (imp.). Beeswax. 

 Spermaceti. 



Compounds of C, H, N (24). 

 Benzonitrile. Aniline. 



Azobenzol. Capronitrile (wk). 



Diphenylamine. Allylamine (wk). 



Dimethylaniline . 



Compounds containing CI or Br (25, 26). 



Chlorobenzol. Chloroform. 



Benzyl chloride. Bromoform. 



Ethylene dibromide. Chlorpicrin. 



Chloral. Acetyl chloride (wk). 



Carbon tetrachloride. Phosphorus trichloride. 

 Sulphur chloride. 



Other Compounds and Solutions (27, 28). 

 Amyl sulphocyanide. Thialdine. 



Allyl sulphocyanide (wk). CI in water (wk). 

 Oil of sage. S0 2 in water (wk). 



