Absorption of ft Rays by Liquids. 185 



which are hygroscopic, were perforce less accurate than the 

 others, but in no case was any deviation o£ the absorption 

 curve from the exponential form indicated. 



Table II. gives measurements made on various masses of 

 water poured on filter-paper in the tray. The results are 

 plotted also in diagram 4 and the deviation from the straight 

 line is obvious. The dotted curve through the observed 

 points is concave upwards for small masses and concave 

 downwards for large. The intermediate part of the curve is 

 approximately straight and from it a value of X/p can be 

 deduced. Taking the observations numbered 3 to 12 in- 

 clusive the value for X/p is obtained, 



6-243 + 0-064. 



Observations were then taken on the absorption of water 

 poured directly into the tray without the use of filter-paper 

 to contain it. Table III. gives these observations which are 



Table II. 

 Water with filter-paper. 



Table III. 

 Water without filter-paper. 



m. 



+ •3475 

 •27.30 

 •2290 

 •1993 

 •1738 

 •1443 

 •1162 

 •0997 

 •0797 

 •0599 

 •0253 



-•0006 

 •0722 

 •1160 

 •1702 



(1) o 



(2) 0-897 



(3) 1-492 



(4) 2064 



(5) 2-585 



(6) 3-158 



(7) 3-673 



(8) 4-087 



(9) 4-560 



(10) 5101 



(11) 5713 



(12) 6-317 



(13) 7-555 



(14) 8-281 



(15) 9-201 



m. 



] og 10 I. 



(1) o 



+ -4160=log 10 T 



1 (2) 1-203 



•3761 



1 (3) 2-262 



•3198 



1 (4) 3-489 



•2615 



j (5) 3-998 



•2297 



(6) 4-442 



•2031 



(7) 4-893 



•1818 



i (8) 5-381 



•1584 



(9) 5-877 



•1290 



(10) 6-355 



■0976 



1 (11) 7-524 



•0302 



(12) 8-736 



-0425 



(13) 9-615 



•1013 



X/p=6-243±0-064. 



X/p =7'176 ±0082. 



also plotted in diagram 4. It appears again that the ab- 

 sorption is not exponential : the dotted curve is concave 

 downwards both for large and small masses. Taking the 

 figures numbered 4 to 10 inclusive, which lie fairly well on a 

 straight line, the value of X/p is obtained 



7-176 + 0-082. 



Various modifications of the apparatus were tried to reduce 

 the curve to its normal form. Changes in the shape and 



