

Electric Wind in Hydrogen containing traces of Oxygen. 453 



small but unknown quantity of air. Other methods gave 

 for dry hydrogen 5*67 and 7*18 as the most probable values 

 of V+ and V-*. 



In the present experiments we found that when more than, 

 say, 0*5 per cent, of oxygen is present in the hydrogen, the 

 values of V by the wind-pressure method are about the same 

 as before (V+ =5*8, V— = 7*6); but in the case of negative 

 discharge alone, a very striking decrease in the values of 

 dp/dz, i. e. increase in the apparent values of V — , is observed 

 as the hydrogen is made purer, the increase being more than 

 forty-fold in the purest gas we could at first obtain. This 

 is shown in the Table of Results, where are collected the 

 bulk of our determinations ; and graphically in Curves I. 

 (p. 454), in which the first and third columns of the Table 

 are plotted together. 



Except where otliencise stated all measurements are given in 

 C.G.s. units. 



Table of Results. 



Negative Point. 



Positive Point. 



Percentage 

 of Oxygen. 



dp/dz. 



Apparent 

 V-. 



z . 



Percentage 

 of Oxygen. 



dpjdz. 



Apparent 



r . 

 0-3 



00 



022X10" 2 



290 



1-9 



00 



-2 



n-ixio 



5-8 





•30 



210 



0-7 





11-5 



5-6 



0-5 





•22 



290 



11 





11-2 



57 



04 





•32 



200 



22 



00017 



10-5 



61 



01 





•31 



210 



1-8 



•0052 



ll'O 



58 



0-1 





•27 



240 



11 



116 



103 



62 



03 





•39 



160 



18 



•33 



11 3 



5-7 



03 



0-0002 



•87 



74 



31 



•94 



10-9 



5-9 



02 



•0003 



1-29 



50 



2-1 



1-77 



11-8 



5-4 



05 



•0010 



•86 



75 



2-8 



373 



107 



6-0 



0-3 



•0027 



1-21 

 115 



53 



56 



20 

 1-9 











•0039 





Mean . . . 



5-8 



03 



•0052 

 •0063 



1-44 

 1-59 



44 

 40 



24 

 25 



















•0124 



2-1 



30 



20 











•0150 



24 



27 



1-3 











•0209 



25 



26 



1-9 











•029 



2-7 



24 



20 











•116 



56 



11-5 



13 











•33 



69 



93 



04 











•94 



89 



7-2 



0-8 











177 



7'9 



8-1 



02 











3-73 



8-7 



7-4 



03 











Mean o 



f last three ... 



7-6 



0-4 



Wiukelmann, Handbiich der Physik, iv. p. 555. 



