Memoirs presented to the Cambridge philosophical society on the occasion of the jubilee of Sir George Gabriel Stokes, bart., Hon. LL. D., Hon. SC. D., Lucasian professor.

;:,.-brib,'</e IP/.gtlosoph.ki/a(l /T7/Ylc~.it t.oP lo!. X II.-, 1?.Plgate.14.
PLATE 1'4.
Absorpltions by solttolutions of erbium nitrate?, cold ai ho>t alteruately, in four degrees of dilution;, i
t.i:k1e.-ss,8s ilt iVe.r:rsol as thle dil.titions, The stlronigest s-ol:.tion hld 566 g'ramts <of eri.) nit-irate.xperx litre,
31.
strotstt t o g tuti sool s
38 mi. thick at 22- C,::::}:::dS înore: difuse, a:n" th:: t::t:i: `:thé badn i -lo.ds a, S 9 ' Ca.
solution 1/4 sltren hgtc:Th s we o min. thick at 23p Ci,,o.
do. at 94-" C,
tl.a: th' repr)odtusolution 1/8 streCilgt a.
't.dSti]lt;in in tshé spXt3rai o thtét. cold305 Moin, thlik ait:3 23' t
oSMj~ ~do.
Cdo. ut 01~ C,.
solution 1/2 stre:ngt
76 miut tMiek at 23> C,
do. ai 97 Co
lt o dll w i-oticcd tIni t totP etlc> of li-tiii % the solution. is il-u oeieral to rendertilr iu absorption
baids: dmd e tiffwse, aind tha, t i i t '.e bauds tIi.P: increweo i utffuhseness witlih inicrcasiug' con.cetra.tion
~of te sod:i toin. whicl are imuost aft. lctetd bv tiît}e rise of teimllcat:île,
Tflic ourginal slibo\N-,tograîds suer,serni fmier bauds whicùi haxe F nt xi couic ont. ici tlue reprodrictioni,
nid lidIso slie.w the lighter ni tcrspaces between tUe. àbsortioîis ii Uic nitra îîiolet niiacl more distintiri
t1han i:the ouc~, r tilt, Even i. the:erodu. ci:on ths light_ intersptt:ces iii the dltra violet arei tîore
distiilet î hiî-I F lie sc ctit of thte eoid sol.uti.orn:s tbhall iii thiiose oft 'te hiot solutionsl