EARTHS. 301 



YTTRIUM. 



1. Not yet obtained isolated. 



2. Yttria converts potassium into potassa, when aided by heat, thus 

 proving the existence of oxygen in the earth, which also exhibits ap- 

 pearances of metallization, so that there can scarcely be a doubt that 

 this earth consists of oxygen and inflammable or metallic matter. 



3. COMBINING WEIGHT. Dr. Thomson assigns 42 as the repre- 

 sentative number of yttria, and supposing that the earth is composed 

 of 1 proportion of oxygen, and 1 of metal, he states the latter at 

 34, for 34+8=42. 



# # * * # * # 



Since the account of the earths was in type,* Prof. Griscom has 

 been so kind as to forward to me the following notice of a new earth, 

 which, as it is so named by its discoverer, I insert here rather than 

 under the metals. The learner will observe that it is a different 

 thing from the substance formerly called Thorina. See note, p. 261. 



Discovery of a new earth, named Thorina, and its metallic base, 

 named Thorium. M. Dulong communicated to the Academy of 

 Sciences at Paris, on the 26th of July last, in a letter from M. Ber- 

 zelius, the discovery of a new earth. " I have just discovered," 

 says the Swedish Savant, " a new earth, which possesses almost all 

 the properties of that which bore the name of Thorina, and which 

 has been ascertained to be only a phosphate of Yttria. It is in con- 

 sequence of this striking analogy, that I have retained the name of 

 Thorina, for this new substance. This earth is white, and irreduci- 

 ble by charcoal and potassium. After being strongly calcined, it is 

 attacked by none of the acids, except concentrated sulphuric, even 

 after being treated with caustic alkalies. The sulphate of Thorina 

 is very soluble in cold water, and almost insoluble in boiling water, 

 so that it may be freed from many other salts, by washing the mix- 

 ture with boiling water. Thorina dissolves easily in carbonate of 

 ammonia. An elevation of temperature occasions a precipitation of 

 a part of the earth ; but on cooling, the precipitate disappears. All 

 the salts of Thorina have a very pure astringent taste, very similar 

 to that of tannin. The chloride of Thorium, treated with potassium, 

 is decomposed with a triple deflagration. There results a gray 

 metallic powder, which does not decompose water, but which, raised 

 above a red heat, burns with a splendor almost equal to that of phos- 

 phorus in oxygen gas. Nevertheless, Thorium is feebly attacked 

 by nitric and sulphuric acids. The hydrochloric, on the contrary, 

 dissolves it with a brisk effervescence. Thorina, or the oxide of 

 Thorium, contains 11.8 oxygen. Its specific gravity is 9.4. Tho- 

 rina exists in a new mineral which has been found in very small 

 quantities at Brevig, in Norway. Bib. Univ. Juillet, 1829. 



* But before it was struck off. 



