SCIENTIFIC SUMMARY. 
83 
CHEMISTKY. 
On the New Element , Scandium . — Cleve has studied the properties of the 
new earth, Scandia, discovered by him a few weeks after Nilson’s announce- 
ment, to which we drew attention {Pop. Sc. Rev., Oct. 1879, 424), in gadoid 
nite and yttrotitanite. The former mineral contains 0002 to 0*003, and the 
latter 0*005 per cent of scandium. Scandia has the formula Sc 2 0 3 , the 
ammonium- and potassium-scandium sulphates, as well as the oxalates and 
selenites, establishing this point. From some eight to ten grammes of scandia. 
by repeated decomposition of its nitrate, one gramme of a white earth was 
obtained. This was converted into a sulphate and calcined, when 1*451. 
gramme gave 0*5293 gramme of scandia, which yields the number 44*91 
as that of the atomic weight of scandium. If scandia be taken to be Sc O, 
the result given above would point to 45*94 as the molecular weight of 
the newly-found element, differing materially from 105*83,. the minimum 
value, as found by Nilson. Careful examination with the spectroscope, by 
Thalen, proved Cleve’s scandia to be pure; it is inferred, therefore, that in 
the 0*3298 gramme of 1 Scandia,’ on which Nilson worked, there must have 
been only 0*043 gramme of the new oxide and seven or eight times as much 
ytterbia. Cleve chooses 45 as representing most closely the atomic weight of 
scandium. Scandia, Sc 2 0 3 , is a perfectly white, light powder, infusible, and 
resembling magnesia. Acids, even the strongest, attack the oxide only with 
difficulty ; it is, however, more readily soluble than alumina. Its density as 
3 > 8. The hydrate, like that of alumina, ss white and bulky. It does not 
absorb carbonic acid from the air, is insoluble in an excess of ammonia or 
potash hydrate, and does not decompose ammonium chloride. Its salts are* 
colourless, with an acrid, astringent taste, quite different from the other salts 
of the metals of the yttrium group. The sulphate does not crystallize dis- 
tinctly; the nitrate, oxalate, and acetate and formiate, on the other hand, form 
crystals. The chloride gives no spectrum when heated in a gas flame. Its 
solution is precipitated by ammoniac and potassic hydrate, and the precipi- 
tate is not soluble in an excess of either reagent. Tartaric acid prevents the 
precipitation by ammoniac hydrate in the cold. Sodium carbonate gives a pre- 
cipitate soluble in excess of the reagent. Sulphuretted hydrogen gives no 
precipitate ; ammonium sulphide throws down the hydrate ; sodium phos- 
phate gives a gelatinous precipitate; oxalic acid gives a curdy precipitate 
which soon becomes crystalline. Sodium hyposulphite and sodium acetate 
at once cause precipitates in boiling solutions ; the precipitation, however, 
is incomplete. The discovery of scandium is of peculiar interest, from the 
fact that its existence and properties were predicted by Mendelejeff , as a con- 
sequence of his law of periodicity, and called by him Ehabor. The remark- 
ably close correspondence between the properties of ekabor and those of 
scandium is shown in Cleve’s paper, by printing them in parallel columns. 
{Compt. Rend., 1879, lxxxix. 419.) 
On Two New Elements, Thulium and Holmium . — Since the ytterbium 
of Marignac and the scandium of Nilson, both of which were discovered in 
erbia, give colourless salts, Cleve endeavours to distinguish the substance 
in this earth which gives the red colour and the beautiful absorption spectrum 
