84 REPORT—1868. 
sodium seizes the chlorine combined with the aluminium, and thus liberates the 
latter metal, which falls to the bottom of the fused mass. 
Aluminium is used in sufficient quantity to keep the only work in England—viz. 
that at Washington—pretty actively employed. Asa substance for works of art, 
when whitened by means of hydrofluoric and phosphoric acid, it appears well 
adapted, as it runs into the most complicated patterns, and has the advantage of 
reserving its colour, from the absence of all tendency to unite with sulphur, or to 
Vaves affected by sulphuretted hydrogen, as happens with silver. 
A large amount of the increased activity in the manufacture referred to is due tu 
the exceeding beauty of the compound with copper, already spoken of, which is so 
like gold as scarcely to be distinguishable from that metal, while it possesses the 
additional valuable property of being nearly as hard as iron. 
This alloy, or aluminium-bronze as it is termed, is a discovery of Dr. John 
Percy, F.R.S., and appears to be a true chemical compound. Copper is melted in 
a plumbago crucible, and after being removed from the furnace, the solid aluminium 
is added. The union of the two metals is attended with such an increase of tem- 
perature that the whole becomes white hot; and unless the crucible containing the 
mixture is of refractory material, a vessel which has resisted a heat sufficient to 
effect the fusion of copper melts when the aluminium is added. 
Mr. Gordon was the first, it is believed, who detected and determined the amount 
of tension wire of aluminium-bronze was capable of resisting, which he found to be 
between that of the best iron and the best steel wire. Colonel Strange, of the Royal 
Astronomical Society, investigated its properties, which were given in a very able 
paper in the ‘Transactions’ of that body. Its malleability, ductility, and capability 
of being finely divided and engraved upon, along with its great strength, induced 
the Colonel to recommend its adoption in the theodolite used in the Trigonometrical 
Survey of India. 
At the Elswick Ordnance Works, Captain Noble, R.A., confirmed previous ex- 
periments on the capability of aluminium-bronze to resist longitudinal and trans- 
verse fracture, and in addition to this he ascertained that its position to withstand 
compression stood halfway between that of the finest steel and the best iron. 
The bronze containing ten parts of aluminium and ninety of copper affords an 
alloy endowed with the greatest strength, malleability, and ductility. The colour 
of the copper is affected by a very trifling addition of the other constituent, and 
the alloy gradually improves in these valuable qualities just mentioned until the 
proportions given above are reached. After this, 7. e. when more than 10 per cent. 
of aluminium enters into the composition of the bronze, the alloy gradually be- 
comes weaker and less malleable, and at length is so brittle that it is easily pounded 
in a mortar. 
On Thallium. By I. Lowrutan Bett. 
The persevering labours of Mr, W. Crookes in connexion with this newly dis- 
covered metal had shown it to exist, in notable quantities, in a sublimate found in 
flues leading from the kilns, in which certain kinds of pyrites are treated for obtain- 
ing sulphuric acid. The author caused the substance found in the apparatus con- 
nected with the leaden chambers at Washington to be examined, and ascertaining 
that thallium really was present, he requested M. Henri Brivet, the chief of the 
laboratories at Washington, to continue the researches and prepare a sufficient 
uantity both of the metal and of its salts for exhibition at the present Meeting of 
the British Association. Some of the results (perhaps all) may have been observed 
by other chemists, but in a subject of such recent discovery as thallium, confirma- 
tion of the labours of others is not without its value. This paper does not pro- 
fess to be more than a record of the various substances obtained by M. Brivet, 
upon whom the entire labour devolved of preparing, and to whom in consequence 
the whole merit is due for the information now submitted to this Meeting. 
The sublimate varies considerably in appearance, sometimes of « whitish yellow 
and at others of a chocolate colour, and these two not unfrequently alternate in dis- 
tinet layers. The reddish colour in the latter is due to oxide of iron and oxide of 
manganese. In both these thallium is to be found in the state of a sulphate, to an 
extent indicated by the following analysis :— 
