364 Mr. R. K. McClung on the Relative Amount of 
TABLE I. 
Relative Ionization in Air and Hydrogen, using different 
bulbs. 
Pressure. 
Date of ree ets P'. 
Bulb. Determination. iP 
ed 
No.1. | Wov.93 | 7662 | B92 ‘| 116'1 Antomatie’Helell aman 
: , 2 | 7654 ; 890 | -116 i ‘ 
s » 2 | 7447 | B40 | 112 | y 
i Deas a ard | ie07 | yar 1 Mi 
st 7412 | 900 "121 m af 
a pie 7412 | 895 "120 | “ i 
4) Jan. 20 WT2 90°3 “Li6 ” ” 
7629 | 808 | -105 , : 
7529 | 630 ‘084 | Non-automatic bulb. 
2 | 7648 | 61:0 | 079 | 2 bal 
| 
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iw) 
UE 
® 
28 
— 
me Or 
i Jan. 16 761°2 51°8 068 fe fe 
, 18 | 7691 | 480 | -062 
” ” 19 1752 47°0 ‘060 a a 
No. 3. Dec. 11 | 7487 | 425 | -056 | . ; 
; 14 | 7561 | 396 | -052 ‘ kK 
No. 4. Jan. 14 7381 | 43°8 "Ud9 “a s 
Different bulbs of course give out different types of rays, 
and even the rays given out by the same bulb under different 
conditions vary from time to time. It has long been known, 
of course, that rays of different degrees of hardness produce 
different amounts of ionization in any given gas. It appears, 
however, from these experiments that when the rays vary 
the ionization does not change in the same ratio for these 
two gases. The change in type of the rays seems to affect 
one gas to a greater extent than the other. The relative 
amount of ionization produced in these two gases is a function 
of the type of rays used to produce the ionization. This 
explains, therefore, how it is that different experimenters 
may get quite different values for the ratio of the amount of 
ionization produced in the two gases. 
The constancy of the results obtained with the bulb in 
which the pressure of the gas remained fairly constant, 
together with the inconstancy of the results from the bulb 
in which the pressure did not remain steady, indicated that 
the difference in type of the rays due to the variability of the 
pressure in the bulb was one at least of the prime factors in 
causing the discrepancy in the ratios obtained for the relative 
ionization in air and hydrogen. To investigate this matter 
the Réntgen-ray bulbs which had been previously used were 
replaced by one which was attached to a Toepler pump, so 
aS ee 
