588 



KEPORT — 1886. 



is filtered. After each fractionation the filtrate is passed to the left and the 

 precipitate to the right, and the operations are continued many thousand times. 



The diagram (fig. 2) shows tlie scheme clearly, with the direction the precipi- 

 tates and solutions travel. Limited space, even on a large diagram, prevents me 

 from giving more than a fevr operations, but they will he sufficient to satisfy you 

 that enormous patience, a large amount of material, and a not insignificant 

 number of bottles, are requisites for successful fractionation. 



After a certain time, on examining the series of earths in the lowest fine 

 of bottles, their phosphorescent spectra are found to alter in the relative 

 intensities of some of the lines, and ultimately diff'erent portions of the frac- 

 tionated earths show spectra, such as I have endeavoured to illustrate at the 

 foot of the diagram (tig. 2), in which I have given the spectra of five com- 

 ponents of yttrium. 



THE YTTRIA SPECTRUM 



FRACTIONATION 



\ 



OF YTTRIA. 



X \ 

 J G) Q) 



x:x:xrxrx X x_ \_ 

 -^-W®x'^®x4^xQx@^ 



CC®x®X®X^®X®xSy3x4*X^'^' 



I mil !i Hill II mil ii 



SPECTRA OF FIVE COMPONENTS OF YTTRIA 



Fig. 2. 



The final result to which I have come ia that there are certainly five, and 

 probably eight, constituents into which yttrium may be split. Taking the con- 

 stituents in Older of approximate basicity (the chemical analogue of refrangi- 

 bUity) the lowest earthy constituent gives a deep blue band Ga (X 482) ; then 

 there is a strong citron band G5 (X 574), which has increased in sharpness till 

 it deserves to be called a line ; then come a close pair of greenish blue lines,. 

 G/3 (X 549 and X 541, mean 545); then a red band, G^ (X 619), then a deep red 

 band, G^ (X 647), next a yellow band, Ge (X 597), then another green band,. 

 Gy (X 564) ; this (in samarskite and cerite yttria) is followed by the orange line 

 S6 (X 609). The samarium bands remain at the highest part of the series. 

 These, I am satisfied, are also separable, although for the present I have scarcely 

 touched them, having my hands fully occupied with the more easily resolvable 

 earths. The yellow band, Ge, and green band, Gy, may in fact be due to a 

 splitting up of samarium. 



Until we know more about these bodies I refrain from naming them, but will 

 designate them provisionally by the mean wave-length of the dominant band. If;, 

 however, for the sake of easier discussion among chemists a definite name is thought 



