346 



BELL SYSTEM TECHNICAL JOURNAL 



It is also significant to compare the coordinate effects of both 

 oxygen-caesium ratio and weight of caesium chromate upon the activity. 

 To this end in Figs. 5 and 6 for the 15 and 30-minute heat treatments, 

 the ratio is plotted as abscissa, the weight of caesium chromate as 

 ordinate, and a circle is drawn about each point whose diameter is 

 proportional to the observed activity. It is apparent that the 3- 

 milligram pellets give superior results for the 15-minute heat treat- 

 ment, and the 5-milligram pellets for the 30-minute treatment. Also 

 the 5-milligram pellets seem to be the better, each considered under 



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-^ — m — — \r" 



I 1 • k m* 



. JL^ 



>^ ¥^" ^^^--~^ ::— -i 



*^^ ' 



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o 



18 22 



OXYGEN TO CAESIUM RATIO 



Fig. 4 — Integral sensitivity as a function of oxygen-caesium ratio for 3 mg. pellets. 



its optimum conditions. The 5-milligram pellets also seem to yield 

 cells more stable with respect to excessive heating, cf. Figs. 3 and 4. 

 The pellet weights were in general quite uniform, but due to temporary 

 difficulties the weights of the 5-milligram pellets used in the 30-minute 

 heat treatment scattered considerably as is shown in Fig. 6. Fortu- 

 nately, this scattering furnishes some detailed evidence as to the 

 relation between activity and pellet weight. The locus of highest 

 activity appears to be an oblique line as expressed in the coordinates 

 of Fig. 6. One might predict that the highest activities would be 



