272 



Prof. Barkla and Miss "White on the 



As absorbing substances, copper, aluminium, water, paraffin- 

 wax, and filter-paper were used. The results are given in 

 Table I. 



Table I. 



Wave-length 

 (Hull & Eice). 



Wave-length. 

 (Siegbahn). 



(M/P) 



Copper. 



typ) 



Aluminium. 



•360x1.0 



■359 



-358 



•355 



•352 



•346 



•345 



•343 



•324 



•323 



•320 



•307 



•303 



•299 



•295 



•292 



•283 



•509x10-8 cm . 



•504 „ 



•499 „ 



•487 „ 



•481 „ 



•477 „ 



•468 „ 



•467 „ 



•460 „ 



•456 „ 



•454 „ 



•444 „ 



•437 „ 



•433 „ 



•426 „ 



•424 „ 



•419 „ 



•413 „ 



•410 „ 



•409 „ 



•403 „ 



•400 „ 



■396 „ 



•394 „ 



•390 „ 



•389 „ 



•387 „ 



•385 „ 



•381 „ 



•377 „ 



•376 „ 



•368 „ 



•361 „ 



•360 „ 



•359 „ 



•358 „ 



•355 „ 



•352 „ 



•346 „ 



•345 „ 



1905 

 18-10 

 17-7 

 16-4 

 158 

 15-4 

 14-55 

 1440 

 1375 

 13-25 

 13-10 

 12-20 

 11-6 

 11-2 

 10-55 

 1040 

 9-98 

 9-60 

 9-31 

 9-28 

 8-76 

 8-55 

 8-24 

 8-04 

 7-82 

 7-77 

 7-61 

 7-47 

 7-15 

 6'94 

 6-90 

 . 638 

 5-98 

 5-92 

 5-87 

 5-81 

 5-58 

 540 

 5-17 

 500 

 4-92 

 4-71 

 4-70 

 4-54 

 402 

 3-77 

 3-71 

 3-68 

 3-47 

 3-20 



1-77 



1-57 



1-28 

 115 



1-06 



1-03 



•847 



•853 

 •815 



: 707 

 •766 



•713 



'643 



•519 



(P/P) 



Water. 



(P/P) 

 Paper. 



■539 



•524 



•547 



■479 



•473 



•436 



•iii' 



•479 

 •396 



: 400 



•388 



•400 

 •351 



■871 









•349 



•329 



•353 



•302 

 ■312 



-328 

 : 389 



•335 







•361 



•311 





■314 



•330 



: 270 



•309 



•271 



•280 



(n/p) 



Paraffin- Wax 



•253 



■317 



•307 

 •302 



•279 

 •267 

 •263 



■252 

 •266 



'258 



•263 

 •254 



•232 



•228 



•232 

 •212 



•217 



