Scientific Intelligence. — Chemistry, 185 



to ^ F. M. 5. That, at this season of the year (November), a 

 circle of cork, with 20 or 30 needles fixed inside of the circle, 

 having all their points nearly meeting at the centre, and sus- 

 pended by any very tenuous filament, is more sensitive than 

 Uiat form of the instrument which traverses on a pivot. — M. W. 



CHEMISTRY. 



8. Metal of Alumina. — M. Oersted is stated to have ob- 

 tained the metal of alumina, by employing the chloride of that 

 earth. Pure alumina is heated to redness, and then intimately 

 mixed with powdered charcoal ; the mixture is introduced into a 

 porcelain tube ; and, after heating to redness, dry chlorine gas is 

 passed over it. The charcoal reduces the alumina, the metal 

 combines with the chlorine, and oxide of carbon is also formed. 

 The chloride of aUiminum is soft, crystalline, and evaporates at 

 a little above the temperature of boiling water ; it readily at- 

 tracts moisture from the air, and becomes hot when water is 

 added to it. By mixing with an amalgam of potassium, con- 

 taining much of the latter, and immediately heating the mixture, 

 chloride of potassium is formed, and the metal of the alumina 

 combines with the mercury. The amalgam quickly oxidises by 

 exposure to the air. Being subjected to distillation, out of the 

 contact of air, the mercury is volatilized, and a metallic button 

 is left, which has the colour and splendour of tin. M. Oersted 

 has ascertained many properties belonging to the new metal, and 

 its amalgam, which he promises to pubUsh speedily. — Phil. Mag. 

 Nov. 1827. 



MINERALOGY. 



9. Largest known masses of Native Platina. — Before Hum- 

 boldt's return from America, small grains only of platina were 

 known to naturalists. On his arrival in Prussia, he deposited in 

 the Berlin Museum a native specimen of Peruvian platina, 

 weighing 1083 grains. For twenty years, this remained the 

 largest specimen in Europe. Since 1822, the Museum of Ma- 

 drid has been enriched with anpther American mass of platina, 

 weighing 11,641 grains. A few months ago, a still more re- 

 markable mass was discovered in the Urals, weighing 10§J 

 Russian pounds. It is deposited in the Museum of St Peters- 



