the Absorption of X-Rays. 199 



is known. Injthe table below are arranged the values of q 

 found in this way, from the table of Barkla and White, 

 corresponding^ values of k 1/H Q (Obs.) calculated from 



the table referred to, and (Calc.) calculated by aid o£ my 

 values of ^1/Cu and Kq/Cu previously found thus, after the 



formula 



= 4-87 + 5? 

 A1/H 2 0-9.1 + 6q 



(15) 



Table XIII. 

 Comparison between observed and calculated values of k^ , h q. 



X. 



P 



V- 



/* 



q= u • 



K A1/H 2 0- 



4-87 + 6q 



P Cu ' 



P AY 



p H 2 0- 





OfrT 



Calc. 



0-91 + 6?' 



0376 



690 



0-802 * 



0-335 



0098 



3-60 



3-58 



364 



0368 



6-38 



0-707 



0327 



0-106 



3-25 



3-51 



3-55 



0-345 



5-00 



0-713 



0-305 * 



0136 



3-52 



3-21 



3-29 



0320 



4-54 



0-622 * 



0-270 



0-149 



3-47 



3-12 



3-20 



O-303 



377 



0-519 



0-265 * 



0-180 



2-95 



2-90 



2-99 



0-283 



3-20 



0-450 * 



0-253 



0-212 



2-69 



2-72 



2-82 



0-266 



2-77 



0-391 



0-226 



0-245 



2-60 



2-56 



266 



0257 



2-58 



0-382 



0-224 



0-263 



2-57 



2-49 



2-59 



0-229 



1-94 



0-300 



0-203 



0-349 



2-22 



2-20 



2-32 



0-212 



1-54 



0-263 



0-199 



0-440 



1-99 



1-99 



2-12 



0192 



1-29 



0-228 



0-196 * 



0-526 



1-75 



1-84 



1-97 



0175 



1-03 



0-210 



0-194 * 



0-658 



1-63 



1-68 



1-82 



0-166 



095 



0-192 



0-194 * 



0-714 



1-49 



1-63 



1-76 



* Inter- or extra-polated values. 



There is a very good agreement between the observed 

 and fl calculated values of « A] m , as the table shows. If 



we compare the values of q that have been calculated 

 in the above way for the medium wave-length used in my 

 experiments with the values resulting from the experiments, 

 we obtain : 



0-678 



I. 



. 0-095 



II. 



0-115 



III. 

 0-139 



IV. 

 0-182 



-Ou 



^obs. 



. 0-067 



0-090 



0-136 



0-195 



The values observed for q corresponding to the radiations 



P2 



