et 3.0 1000-2800 3.3 1000-2800| 2.0 800-2800] Z.5 2.3 5 1000-1800 2.1 1.5 1.5 159-1050/2.0 86-1050/2.5 2.5 160-1260]2.5 200-1050 150-1450 100-1050 1.€ & 110-1050]2.4 b 160-1050]1,6 1.4 b 150+1050/ 2.2 L 210-1050] 2.3 45 § a 15 3) 5 800-2800} 1000-2800] 750-2600! 120-2250 120-2250 1050-2300 1050-2300 1050-2300 1160-2250 1030-2300 1050-2300 1050-2300 ©2120-2300 1050-2300 1050-2300 150-1050/ 2.5 200-1050/ 2. 1100-2300 1050-2300 } oocdgeor 100-2500) S 2 210-1050/2.4 1050-1160 2 200-1050/2.4 1050-2300 1.6 140-2300 + 101b 2 2 ) 300-21 oo 1160-200 i 1$0-1050/2.5 1050-2300 1.2 300-2300 ' wl.l 100-1460/ .8 b 100-1160] 300-2300 1460-2300 Y 50-"960/1.8 t a. A as I ee ee eee ee considered to be uncertain, or where the gap between points was so hye & 3 Jalenctte we .8 1160-2300 1050-2300 .2 1450-2300 75-1160 180=1050])1.9 105052300 65=1050/3.7 150-1160)0.1 1050-2300 1160-2300 TOO-1050)" 150-1050] 9 1050-2300 .3 1050-2300 .6 300-2300 »06 200-2300 219-1050] .25 1050-2300 100-1000/2.5 1050-2300 1.3. 50-2300 140-1050/ 2.5 42-1050) 2.0 0 1050-2300 1050-2300 00-2 “100-1650, .85 1050-2300 70-1050) 2.4 1050-2300 1050-1460; .03 1460-2300 -63__$00-2300 100-105012.5 1050-2300 75-1050 2.5 1050-2300 200-1050) 2.5 1050-2300 400-1000 2.2 1000-2300 2.5 1050-2300 200-1000, .5 1000~2500 90-1050] 2.5 1050-2300 100-1050 2.5 100-1000] 2.2. 150-1050, 2.2 1.7 250-1050) 1000-1160] 1050-2300 1000-2300 1050-2300 160-2300) * 1.7. 200-2300 1.5 140-2300 .3 1050-2300 .6 1160-2300 2.5 1050-2300 2.5 80-1050) 2.9 1000-2300 1050-2300 1050-1450/1.5 1460-2300 200-1050) 2.6 200-1050] 1.7 great as to cause difficulty in perceiving the continuity of the curve. § * a ; From the original graphs the curves were copied over onto tracing paper. A somewhat natural sequence of subject matter was arranged, progressing from soil kingdoms. a light-table through the plant and animal Each graph was oriented by means of the 1000-day verti- cal line. Thus, the position of the curve in the series is no index of the amount of radioactivity involved. Absolute levels may be computed 960-2300 -97§-1050/2.2 1050-1450] | by referring to the column of Table 1 headed "Plate count, 1000 days." For example, if for curve 25, the value of the plate count at 2300 days were required, then reference to Table 1 would show a plate count at 1000 days of 700, while the ordinates as scaled from Figure 1 on days 1000 and 2300 were 18 and 2.4 respectively. The ratio, 2.4/18, is multiplied by 700 to give a result of about 93 c/m, which is reasonably close to the actual value, 90 c/m (original data, not shown here). Slopes of curves were scaled from the finished drawings of Figures 1-6, using a transparent slope-scaler calibrated in tenths from slope 1050-2300 1050-2300 -O.1 to -2.0 and by greater increments from -2.0 to -5. For each 100-1050) 1.0 1.0 «5 1050-2300 280-2300 200-2300" 176-1050] 2.3 1050-2300 7O-1050' 2.2 100-1050! 2.5 1050-2300 1050-2300 thus necessitating subjective interpretations as to what constituted a change 70-1L000i~2 100-1050/ 2.2 1000-2 300 1050-2300 of slope. 100-1050] 180-1050; .@ 1050-2300 .4 1050-2300 2.1 100-1100) 2.2 130-10£0/ 2.5 200-1000] 1.3 70-1160/ 2.5 200-1160/ 2.7 7O1050/ 2.5 100-_960/2.2 2.3 2.3 100-1050: 2.2 100-1050, 1,0 1050-2300 1100-2300 1050-2300 1000-2300 1160-2300 1160-2300 1050-2300 960-2300 1050-2300 1050-2300 1050-2300 1050-2300 ae wwe me get . curve, the portions of markedly different slope were measured separately,