Chemistry and Physics. 427 
gram of CO,, until neutralization is effected. From the data thus 
given the weight of the carbon dioxide is calculated. ae iiss 
Soe., Xxxvii, 493, July, 1880. 
2. On the "Atomic Weight of Ytterbium.—N ison mad ecctaeel 
his researches upon the rare elements of the satan enite, ee 
seven different oxides, i yiterbia, pears erbia, terbia, the 
earth which Soret calls x, and yttria. ‘To extract them, the finely 
pe tatised mineral wa s placed i in a platinum “dish, in ‘quantities of 
about 400 grams, mixed with four times its weight of hydro- 
potassium sulphate, and fused over a powerful gas lamp. The 
n was com rae extracted with cold sere decanted from 
OBR metallic acids, precipitated with ammonia, the 
hydrates thus obtained washed out, dissolved i in nitric acid, boiled, 
nitrate evaporated and fused until the weight was twice that of 
the mixed earths. On solution in water, a residue remained of 
basic nitrates of thorium, cerium, uranium and iron. The filtrate 
gave a beautiful fused nitrate, which was subjected to the long 
series of partial decompositions already pr ey aoek ibed. The 
Strongest bases, didymium, yttrium and terbium accumulated in 
the first. mother- “liqu uors so that the ices: solution after seven 
decompositions, contained no didym In the mother-liquors 
from 8 to 30 the abso orption-bands of she so-called erbia increased 
successively in intensity, the solution containing finally nearly 
the whole of the earths which are characterized by bsorption 
bands. Cleve 5 wiley ee ae 15 kilograms of gadolinite at 
had 
Pare pi pure "ytter rbia.* The solution of the nitrate pi? sone 
h H,S, and the filtrate precipitated with oxalic 
eae was ignited, the earth converted into nitrate i ‘livided 
* Serie s 61-68 contained, Seeide seri only os oxide of a on to which 
Cleve ity given the name of thuliu 
. 
