X, A, 1 



Blackwood: Radioactivity of Atmosphere 



41 



Table I. — Diurnal variation of active deposit. 



[Length of wire, 80 meters ; voltage, 8,000 ; time of exposure, 30 minutes.] 



Date. 



Time af- 

 ter mid- 

 night. 



Recipro- 

 cal of 

 time for 

 leaf to 

 move 40 

 divisionB. 



Relative 



humidity. 



Wind. 



Direc- 

 tion. 



1 



Force in 



kilo- 

 meters 

 per hour. 



1914. 

 Jan. 26 



Hrs. 

 10 

 19 

 21 



24 

 3 

 5 

 6i 

 9 



m 



15 

 17 

 20i 

 20i 

 i 

 2 

 3 

 4 

 6 

 6i 

 9i 

 lli 

 13 

 19 

 20 

 1 

 2 

 3 

 3i 

 6 

 6 

 9 

 12 

 16 

 18i 

 20i 

 21 

 24 

 3 

 7i 

 81 

 UJ 

 14i 



I6i 



8 



9 



12 



14 



0.028 

 0.008 

 0.018 

 0.050 

 0.143 

 0.121 

 0.033 

 0.033 

 0.022 

 0.016 

 0.018 

 0.019 

 0.018 

 0.014 

 0.012 

 0.033 

 0.121 

 0.091 

 0.025 

 0.020 

 0.033 

 0.050 

 0.007 

 0.033 

 0.033 

 0.050 

 0.062 

 0.100 

 0.050 

 0.036 

 0.030 

 0.033 

 0.026 

 0.009 

 0.013 

 0.013 

 0.030 

 0.125 

 0.025 

 0.017 

 0.017 

 0.014 

 0.015 

 0.008 

 0.025 

 0.017 

 0.011 









Jan. 27 









Jan. 28 







. 1 



Do 









Jan. 29-. — 









Do . - . . .- . 









Do 









Do ...- 



Do 















Do 









Do 









Do . 









Feb. 2 - - 



76 



83 

 86 

 86 

 88 

 86 

 92 

 79 

 72 

 68 



82 

 89 

 83 

 91 

 91 

 93 

 93 

 68 

 55 

 48 

 58 



ESE 

 Calm 

 Calm 

 Calm 

 Calm 

 Calm 

 Calm 

 SSW 



sw 



SE 



Calm 



Calm 



Calm 



E 



NE 

 NE 

 Calm 

 Calm 

 ESE 

 EbyS 

 ESE 

 ESE 



8J 



2 1 

 



1 



1 



3 



3i 



9 



8 i 



1 



Feb. 3 .- 



Do 



Do . . 



Do . . 



Do 



Do... -. . . 



Do _ 



Do 



Do :.- 



Do ... 



Feb. 4 



2 

 3 

 6 



* 

 4 



3 



2i 

 16 



22 i 

 20 i 

 16 



Feb. 5 



Do 



Do...- 



Do.. 



Do. 



Do 



Do 



Do - 



Do . . . 



Do 



Do 



Feb. 9- . . 



74 

 84 

 77 

 80 

 62 

 58 

 69 

 63 

 66 

 55 

 65 

 46 



ESE 

 Calm 

 Calm 

 Calm 

 NE 

 NE 

 Calm 

 NNE 

 Calm 

 EbyS 



w 

 w 



8 



li 



li 





 12i 



9i 



Do .. 



Feb. 10 _ 



Do 



Do 



Do 



Do 



5t 



Do 



M 



Feb. 16 



.■J 



Do 



4i 



Do - 



17 



Do-- 



10 1 



