ON WAVlM.KNfiTH TAIIM'.S OK TI[E SI'KCTHA nV TIIM KLK.MKMS. 



,>.)\ 



,■),--;',(; I. 



II-SIG. 



li'Vi' ' [3] i.\. 

 Sue' V. •-'Hi 



. Mi.s.' [:.i 



t : ' Am. .1; 



i;7 (Al>s.); 

 ,' viii. ;ii 

 (!>■ I'hya.' [2] 



(Abs.) 



. Chfiii.' N.F. 



xxvi. .s7-aS; 

 •[r>]xvi.ll)7- 

 ililiitliT,' vii. 

 Uis.); 'Zi'it- 

 nslrumoutcn- 



, i.W riiys.' [2] 

 5 (Absi.) 



] xxvi. 211 ; 

 ;[5]xvi.210; 



• viii. :vi 



a.' l>liys.'[2l 

 (Abs.) 



ii. 707-708 



.")] xvi. 1577- 

 jliittor,' viii. 

 '.I.do Pliys.' 



I.-. I (Abs.) 



-chilli, nisst'.' 



.-rliiiii. I'lisso,' 



.i-liiui.nisse. 



-cliim. rns-i', 

 i. 

 rsachr." 18!JJ> 



RrjKirl 0/ l/if ('(miii>'tlle.(\ consistin;/ of I'rofcssor Sii" H. !•]. lidticoi:. 

 .Mr. .1. N. IiO('Kvi;i!, Profcs.'^ors Dkwak, Wolcott (iiims, |,ivi;ing. 

 Stiii'sTiiH, (nid W. N. Hautlky, Captuiii AiiNKV, iind Dr. Mahsiiali, 

 W yn's(S<'n'el(iri/), (i^ipoiided foi' llic pn rjxisc of iive/xi ri 111/ n, new 

 mcriey <>f Wdi'c-lcnrjth Tah/eKS of I he tSpecli'd of t/ie KUiiii('u(t<, 



In tlio fi'llowiuf^ tables arc ijroiijrli^ to'^otlior flio cliiof mcasiironuMits of 

 the wavf-loiiijtlis of tlio bii^^lit lines constituting^ tlio spectra of the 

 cloiiiciits. iiMil of certain compounds, so fivr as tliey are known to tlin 

 Coiiiiiiittee or have proved accessible. The nieasiiveniciit^ arc j^ivcn in 

 ti'ii-iiiillioiitlis of a millimetre (or tenlli-niotres), and arc baaed upon the 

 mciisurc nients of the KraunlioCer lines by Angstnim for the visible rays, 

 and the extension of the same series of measurements into the ulti'ii- 

 vidlct portion of the spectrum made by Cornu and other ob.scrvers. It 

 will he well to brinn- to<retlier here these fundamental values of wave- 

 Iciiirth of the chief solar lines. The small corrections indicateil at nasre 

 •JO of Angstnini's Memoir, ' Lo Spectre Normal du Soleil.' liave been 

 applied to his numbers — but they are uncorrected for the dispersion of 

 uir. J leneo the numbers in the tables n-present wavc-lonj^ths in air of 

 7(Ii)'""' pressure at Upsala, and IG° C temperature. The numbers taken 

 iVoiii 'I'halcn's ' Determination des fiongeui's d'Ondc des Jtaies j\lctalli([ucs " 

 in the same way have had applied to tlu'm the necessary small corrections 

 to bring them into harmony Avith tlie numbers finally adopted b\ 

 Augstriim as ' Yalcnrs definitives ' (pp. 25 and ol-IIi). 



FjiAuxnoi'Ki! I>i\i;s 



KIUO' 



symbols arc employed in the tables to indicate the 

 character of the lines : 



.s (Iciiiitcs that the line is sharply (Icfiiicd. 



11 (leni)tc.s that tin- line is ill-dctinod or nebulous. 



h denotes a band, the ])Osition ol' the brightest i)art liein,;;' gi\en. 



b' denotes a bajid .sharply delincd on the least refracted .^ide, and fadiuL;- a\va_\ 



towards Ih;' Idue. 

 b^ denotes a liand sharply defined on its more refracted .■^ide, and diii;jf a\va_\ 



towards the red. 

 <■ denotes that the line is continuous. 

 'I denotes that the line; is discontinuous, or a 'short ' line. 

 V ilenntes that tlie line is frecjuently ' reversed.' 

 A number within parentheses, thus: (ItOHFK), means that while a line in this 



position has been ob.served, no new measurement oC wa\e-leugtli was made 



— the wavedi'Ugth beingquoted from another observer. 



The intensities of the lines are expressed upon an ascending scale 

 from 1 to 10 ; 1 being the feeblest and 10 the brightest. 



