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.

6(tC bri'tCde lM.tkiosop/ica2 l 7'rai.sacttions, 'I:.0 XVtI, Plates 8, 9.
PLATE 8,
Absorpti)ons of a solution of erbium nitrate containing 467'6 gra ms of the sait 1per litre, and. of a1
S)olutiolt, }ade by U di]lutino t thoe rl'er to 4,5)'5 times its bulk,:0 ïA -4 1 -J ppt 7H: tO
i~~~ ~~~~~~~ -l'';:-:~i;' stronger solution
6-7 miin thick
1/45'-5 strength;'305 mm. thickç.
The t bads are more diffuse with the stronger. solution, that t about X377 being decidedly broader.
Tfl.e bttand at about X44.9 is more distinctly seen in the original and is more diffuse with the istronbger
solutionn tlhani wit tle weaker,
PLATE 9.
Absorptions by solutions of eJbnl chllorîide of concentrations equivalent to thLose of the nitrate used
for plat.te 8; thré stronger solution contaiining 363'3 grams t of the salt per litre.
cc ct 00 Coa T^ 0 L L
î-0 i-% ^ - -^ ---- - ---
1/45' strength
305 mni. thick
stronger solution
6'7 min. thick
Trlere is hardtlIv a difference betw-een. these two spectra except that the bau)cJ-d about À377 is rat aher
stronteÇr citfhi théu more concen.tratedt thaui withi the dilite solution, owing probably to tlie overlapping
of the general diffuse absorption of thie concentrated chloride at the more refritangible end. The fainter
bands which are visi-ble i the original photo!raph ca.n hardly be traced in the reproduction.