the Spectrum of Copper. 461 



lines for m = 3....6 whose wave numbers are 55031-92±1*30, 

 57710*49±*75, 59141*05±*5, 59994-15 in which the am- 

 biguities are due to possible errors in P x (2). These all lie 

 in the ultra-violet region of Handke. In comparing observed 

 with calculated it should be remembered that Handke gives 

 his measures to *1 A., whilst dn varies from 28 d\ to 40 dX. 

 Consequently any value of dX between +'05 is equally 

 probable or of dn between limits varying from 1*4 to 2. In 

 addition are observation and standard errors of which no 

 estimates are given. The formula for P : is 



| m + -891742- * \ . 



m = 2. 49069. This gives Pl (1) - Pl (2) == 18286*87 ±2*4. This 

 is not observed, but an observed line n= (2 n) 18475*93 

 treated as p 2 (1) — p 2 (2) gives the P (2) separation as 

 59*38 zb, the expected amount. 



m = 3. [55031-92 + 1-30]. There is an observed line at 

 (lj 55026-69-30 dX. Also (2 n) 24245*24 (*6) as 

 ^i(l)-j»i(3) gives P 1 (3) = 55028*01±'6. 



m = 4. [57710*87 + *75]. There is an observed line at 

 (4) 57723*4- 33 dX. 

 Also (2n) 26931-74+-3 asp 1 (l)-p 1 (4) gives 



P 1 (4) = 57714-51±*3. 

 (2 n) 27188*69 as p 2 {l) -p 2 (4) gives 



P 2 (4) = 57723-23±-4. 

 The former supports the calculated P 1 (4). The second 

 is the observed, but it is curious that P 2 should be seen 

 and P x absent. 



3n = 5. [59141-05zf5J. This is not observed, but it is 

 connected by it-links to lines on both sides. Thus 



u. (8)59822-9 = 59142*24-36^, 

 (6) 58459-0. u = 59139-70-34cZX, 



an exact series inequality. 



Also (2n)28366-38 as j>i(l)-jpi(5) gives I\(5) = 



591 49*15 db'8, probably P 2 with no observed P x as in 



the previous order. 

 m = 6. [59994*15]. This is not observed, but there are 



r-linked lines for P ls P 2 , viz. 



(6) 59297-9 . v = 59989-9-35 dX 

 (8)59290-9 .v = 59982-9-35 rf\. 



These would give theP(6) separation as 7 — 35 (d\i—d\ 2 ) 



= 7+3*5 as against a calculated value of 4. It thus 



aorees within equally probable errors. 



Also [2n) 29212-61 as Pl (l)- i?1 (6) gives Px(6) 



= 59995*38-h*8 — also to the violet of the linked lines. 



