Experiments on various Liquids. 249 



Mercaptans, 0„H 2)l+1 HS. 



14. These are purely positive, and rise in power as n in- 

 creases ; they are stronger than the corresponding fatty acids. 



Ethyl hydrosidphide acted very well in the plate cell as a 

 conductor, without the jar. The effect from extinction was not 

 very faint, and was slow enough to be characterized as purely 

 positive. 



Butyl hydrosidphide is distinctly stronger. As a noncon- 

 ductor, it gave a faint but clear effect, which was purely posi- 

 tive ; and as a conductor, with increasing charges of the jar, 

 it gave a set of increasingly brilliant effects, which were all 

 strengthened by tension parallel to lines of force, and all weak- 

 ened to perfect extinction by the proper compression. 



Amyl hydrosidphide, not a clean sample, acted very like the 

 last, but was rather stronger. As a nonconductor (spark 

 £ inch) it gave a good though faint effect, which was purely 

 positive ; and as a conductor, with moderate charges of 

 the jar, it gave an intense restoration, which was always 

 extinguished perfectly by the proper compression parallel 

 to lines of force. 



Formates, CH(C il H 2M . 1 )0 2 . 



15. These are active only as conductors, and certainly posi- 

 tive ; but the effects are faint and impure, the flame restored 

 in the polariscope being distorted and streaky. This form of 

 disturbance was noticed already, though in a milder form, in 

 the allyl and ethylene alcohols. 



Methyl formate, with moderate charges of the jar, gave an 

 effect which was faint and not at all pure, but certainly posi- 

 tive, strengthened by tension parallel to lines of force, and not 

 sensibly affected by compression. 



Ethyl formate, with good charges of the jar, acted rather 

 better. The effect was strengthened by tension parallel to 

 lines of force, and much weakened by compression. 



Amyl formate acted very like the other two. With mode- 

 rate charges, the effect was pretty strong and distinctly positive, 

 strengthened by tension, and either weakened or not affected 

 by compression. When the discharges were intense, the dis- 

 turbance masked the regular effect completely. 



Acetates, C 2 H 3 (C B H 3B+1 )0 2 . 



16. These are distinctly positive, and otherwise like the 

 formates ; but the effects are purer. 



Methyl acetate required the jar. With moderate charges 

 the effect was very abrupt but certainly positive, strengthened 



