208 NOTES TO BOOK XIV. 



perpetuate his memory by establishing in his honour a 

 Professor of Chemistry at Manchester. 



(i.) p. 171. M. Schroder, of Mannheim, has endea- 

 voured to extend to solids a law in some degree resem- 

 bling Gay-Lussac's law of the volumes of gases. According 

 to him, the volumes of the chemical equivalents of simple 

 substances and their compounds are as whole numbers, 

 (Die molecular-volume der ChemiscJien Verbindungen in festen 

 und flussingen Zustande, 1843.) MM. Kopp, Playfair and 

 Joule have laboured in the same field. 



(K.) p. 201. The last few years have made some, at 

 least some conjectural, additions to the list of simple sub- 

 stances, detected by a more minute scrutiny of known 

 substances. Thorium was discovered by Berzelius in 1828; 

 and Vanadium by Professor Sefstrom in 1830. A metal 

 named Cerium, was discovered in 1803, by Hisinger and 

 Berzelius, in a rare Swedish mineral known by the name 

 of Cerit. Mosander more recently has found combined 

 with Cerium, other new metals, which he has called Lan- 

 thanium, Didymium, Erbium, and Terbium : M. Klaus has 

 found a new metal, Ruthenium, in the ore of Platinum ; 

 and Rose has discovered in Tantalite two other new metals, 

 which he has announced under the names of Pelopium and 

 Niobium. Svanberg is said to have discovered a new 

 earth in Eudialyt, which is supposed to have, like the 

 rest, a new radical. If these last discoveries be confirmed, 

 the number of simple substances will be raised to sixty-two. 



