Air in Closed Vessels and its Causes. 

 Iron. 



56 ( 



Mean ...-300 



Mean Ionization | fa£££&f'" i% Proportionate Diminution ^percent. 



Alu 



minium. 



Unscreened. 



Screened. 



U 



nscreen 



ed. 



Screened. 



U 



n screened. 



•276 



.002 





•255 





•207 





•216 



■261 



•222 





•246 





•214 





•249 



•276 



•206 





•246 





•230 





•24:; 



•261 



•214 





•255 





•246 





•250 



Mean ...*268 



•216 





•250 





•224 





•247 



Mean Ionization j ^eeS ' ' ' "220 Pro P orfcionate Diminution 13\ per cent . 







Zinc. 







Unscreened. 



Screened. 



Unscreened. 



Screened. 



Unscreened. 



■238 

 •230 

 23S 

 •206 



Mean ...228 



•168 

 173 



•176 

 157 



■168 



•261 



•206 

 •217 

 ■209 



is 



•171 

 165 



167 

 169 



•168 



" -222 : 



•238 

 •254 

 •214 



•232 



Mean Ionization \ Unscreened... '2-8 p rop0 rtionate Diminution .^-percent. 



Similar experiments were now made with an iron screen . 

 This screen consisted of large rectangular blocks of iron about 

 5*5 ems. in thickness. The results are tabulated in the same 

 way as before. 



Lead. 



Unscreened. Screened. Unscreened. 



Screened. 



Unscreened. 



•529 -149 -566 

 551 -445 -518 

 •540 '485 "502 



•524 "491 524 



Mean ...'536 '467 527 



179 

 ■46] 

 ■485 

 ■485 



177 



■518 



•496 

 •507 

 •512 



•:,i is 



■Mean Ionization 



Unscreened... '524 



Screened '472 



Proportionate Diminution 10 per cent. 



