attending the Efflux of condensed Air and Steam. 335 



u-5^^^'''T\ P.';^'^"''^ ^l ^•"'^h I couk] detect positive elec- 



IS T h i'"' '''''' '"""^'^ '''^ '^'^'"^ ^^ that at which ne- 

 gative electricity first appeared ; and an increase of pressure, 



Sn.i Jnf ^r"S "? P°""^' "" ^'^"^ '"^'^' '^"g-^ented the in' 

 w e ^hl ^^^'^^^^'^P'"^"^ ,n the same ratiot apparently, as 

 when the boiler was negative; but further additions to the 

 load on the valve were attended with very variable results 

 sometimes increasing, and sometimes diminishing the electril 

 con;id.lM"'^'' remarkable circumstance, however, was that a 

 'nstanrT. . '""■'"'" of Pressure always produced in thefirst 

 boiler whi.rr''''7 recurrence to negative electricity in the 

 boilei, which lasted for a minute or two, and then airain 



fffmt o'c ''^"'!;T ''r''"^'''' ^ ^"^P-^ t»-t this ciS 

 r^f H , ^"'"^ ^^ ^^' '''^"' ^"^ ^^ter acquiring an in- 



iwfon fTT'"'' T'^ '-fPidly than the metal of the upper 

 pait of he boiler, so that when the boiling point correspond- 

 ing to the load on the valve is again attained, the meta in 

 contact with the steam is not at fii4 hot enough to reverse the 

 natural electrical state of the boiler. If this'view of the s^b! 



Sa'trnTV'/fr^ '""f ''r'^^''^' «^' »^-' which is ne- 

 cessa.y in the metal to render the boiler ;;o5//.Wj/ electrified 



pS;.:SXhr.'i':°'''"« '-'■■"' "' *'---' -" "• "•-- 



When the pressure was considerable, the tendency to ne- 

 gative electricity in the steam-cloud was greatly increased bv 

 passing the steam through the copper pipl acte^d upon by the 

 fi.e; so much so indeed, that I could frequently obtain a iet 



that a jet of steam posit welj/ electrified was escaping from the 

 valve. At low pressures, however, the effect of passing the 

 s earn through the pipe was rather the reverse of what uZl 

 mentioned, and I therefore scarcely know whether to rec^ard 

 the result as favourable or adverse to the agency which! 

 have ascribed to heated metal. ^ -^ 



By much the most powerful effects were obtained when 



n tl TolleT WI "'^.f ?r"^' ^^'"•^ S'^- ^"^- '"-'S 

 in tne boilei. When the tube was long a considerable mn 



etcS;r'tiri"7'T." ''. ^'^^^-^ ^'^^''y <^^^^^^ 



whpn t£ 1 -I ^^- ^'.^ electricity was seldom so strong, 

 when the boiler was positive, and the steam-cloud ne^rative" 

 as when they vvere m the opposite and usual states. " ' 

 The neutrality of the steam in the boiler, whether the 

 steam-cloud evolved positive or negative electric ty, wascLr v 

 evinced by the e ectricity of the jet not being ab.Sed bv pas/ 

 ing the steam through the copper pipe, winch w^teifee't 

 long, and only three-eighths of an inch in diameter 



