296 Proceedings of Societies. 
with the manufacture of aluminium-bronze. ‘These considerations have 
led manufacturers both here and in France to adopt the use of another 
raw material for the production of aluminium, which either does not 
contain the impurities referred to as so prejudicial, or contains them in 
such a form as to admit of their easy separation. This material is 
Bauxite, so called from the name of the locality where it is found in 
I'rance. It contains— 
Silica, . , , : : : 2°8 
Titaninm,' * 3 ‘ s , : 31 
Sesqui-oxide of i iron, : : 25°3 
Alumina, ’ ; , ; , ; 57°4 
Carbonate of lime, a; 0'4 
Water, . ‘ ; i ; 10°8 
The Bauxite is ground and mixed with the ordinary alkali of commerce, 
heated ina furnace. The metal is so extensively used in the arts as to 
keep the only work in England, namely, that at Washington, pretty 
actively employed. As asubstance for works of art, when whitened by 
means of hydrofluorine and phosphoric acid, it appears well adapted, as 
it runs into the most complicated patterns, and has the advantage of 
preserving its colour from the absence of all tendency to unite with 
sulphur, or become affected by sulphuretted hydrogen. A large amount 
of the increased activity in the manufacture referred to is due to the 
exceeding beauty of its compound with copper, which is so like gold as 
searcely to be distinguishable from that metal, with the additional valu- 
able property of being nearly as hard as iron. 
** Report on the Chemical Nature of Alloys.” By Dr Marraixzsen. 
“On the Extraction of Thallium from the Flue Dust of Pyrites 
Burners.” By W. Crooks, F.R.S. 
“On the Impurities contained in Lead, and their Influence on its 
Technical Uses.”” By W. Baxer, F.C.S 
“On the Slaking of Quick-Lime.”’ By Dr Joun Davy. 
‘On Molecular Motion.” By Dr Zunner. 
‘¢On the Analysis of Chinese Iron.” By Dr Stevenson Macapam. 
‘“Définer par la végétation |’état moleculaire des corps. Analyser la 
force végétale par des essais raisonnés de culture.” By M. Gro. ViLxe. 
‘¢ Report on Synthetic Researches on the Formation of Minerals.” -By 
Mr Apuonse GaGes. 
“On a New Method of Measuring the Chemical Action of the Sun’s 
Rays.” By Dr F. L. Puirson.—The writer happened to notice, lately, 
that a solution of sulphate of molybdiec acid (that is, a solution of molybdic 
acid, or molybdic ammonia, in excess of sulphuric acid) standing in his 
laboratory upon a shelf which is partly exposed to the sun for about three 
hours each day, became bluish-green in the daytime and colourless at 
night. He repeated the experiment several times, and found that the 
saline solution when exposed to the sun was reduced, but when withdrawn 
from its influence, it gradually became colourless again by oxidation. No 
evolution of gas, however, was observed. During the insolation a certain 
amount of the molybdic acid loses one equivalent of oxygen, which com- 
bines with the water and forms oxygenated water, and during the night, 
the latter gives back its oxygen to the molybdic acid produced ; the whole 
being in presence of an excess of sulphuric acid. Nothing is easier than 
— —_—S r= oe oS 
