Precision-Measurements in the X-liay Spectra, 679 



Besides the /^-lines in Table II., the following are em- 

 ployed : — 



BaLft X=25G2-35 X.U. 



KKfl! X = 3733-86 



AgLfr \ = 3926-56 



MoLft X = 5166-44 



The results of the measurements are given in Tables IV.-VI. 

 Here \ g is the value of a obtained with gypsum and calculated 

 with Bragg's formula ; r3\, the difference between the value 

 and the wave-length \ c , obtained with calcite. The last 

 column contains "d\ in per cents, of \ c . 



Table IV. 

 First order. 



Line. <p ls . A^X. U. q\. — - — . 



Va/3 X 8° 39' 8"-3 2279*90 4-0-22 0-009 



Ti ft 9 31 43 '2 2508-82 +0-08 0-003 



Baft 9 44 7-1 2562-71 +0-36 014 



Sc ft 10 32 49 -0 2774-00 +0-34 0-012 



Caft 11 4110-2 3082-71 -026 0-008 



K ft 13 S 37 -1 3446-08 -0-30 0009 



Agft 15 56-3 3926-45 -0-11 0003 



CI ft 16 51 13 -0 4393-90 -0-60 0-014 



Mo ft 19 55 48 5166-00 -0'44 009 



Table V. 



Second order. 



Line. 18 . A^A.U. 5A. — - — . 



Ya-ft 17° 29'57"-8 2278-53 -145 0-050 



Ti ft 19 19 21 -6 2507-33 -L41 0-056 



Baft 19 45 14-9 2561-12 -123 0-048 



Caft 23 59 31-0 3081-14 -L83 0-059 



K ft 27 2 15 -2 3444-62 -1-76 0-051 



Agft 31 1116-9 392400 -2'56 0065 



Mo/3, 42 57 11 -1 5163-44 -300 0058 



Table VI. 



Third order. 



> Vtt ^ 100 (U 



Line. 18 . a^a. U. (j/\. — — — . 



Vaft 26°48'28"1 2278"31 -L37 0060 



Baft 30 27 15-0 2560-47 -1'98 0077 



Oa/3 1 37 33 47-2 307971 -326 106 



K a x 47 36 2-6 3730-42 -344 0092 



