288 Scientific Intelligence. 
This alloy has been selected by Col. Strange as the most appropriate 
metal for the construction of the large theodolite for the use of the Trig- 
Spe Survey of India. The horizontal circle of this theodolite is 
three feet in diameter, and the effect of using this alloy will be to keep 
- aah of the instrument within reasonable limits, notwithstanding 
ts possession of pa and appliances not hitherto bestowed on suc 
ser uments, In manufacture of the alloy, Col. Strange says that ex- 
tremely pure copper must be used ; cletrouype copper is best, and Lake 
Superior soppel stands — giving an alloy of sla hited - 
ence of iron, which appears to be snopialty prejudicial, Parte the hiloy 
must be melted two or three ones as that obtained from the first melting 
is excessively brittle. “Each successive melting, up to a certain poin 
determined by the working, and particularly the { forging pate of the, 
metal, improves its tenacity and strength. It is probable that after sev- 
eral meltings there will remain in combination with the copper a some- 
what smaller proportion of aluminum than 10 per cent. The present 
price of English-made 10 per cent aluminum-bronze is 6 shillings 6 pence 
er Ib, This is four or five times that of gun-metal, but a much smaller 
quantity of the new alloy than of gun-metal will give the same strength; 
and when it is considered how small a ratio the cost of material bears to 
the cost of workmanship 1 in refined apparatus, it will be found that even 
at the present price of the new alloy its cost is not prohibitory, w whilst the 
advantages attending its use jp Sax to outweig the increased expendi- 
ture.”’—L. E, and D. Phil Mag., [2], xxiv, 
C. Tisster, Director of the Aluminum Works at Rouen, shows that one 
per cent of aluminum in copper makes the latter more fusible, giving it 
the property of filling the mould in casting, at the same time preventiog 
it from rising in the mould. The action of chemical agents upon it Is 
also weakened, and the copper ae n hardness and tenacity without 
losing its malleabili ity, thus proving a an ‘alloy which has the malleability 
of brass, with the hardness of : 
In transverse sirongsh this silo was found to be more than twice % 
rigid as either brass or copper. ‘Tissier also finds that one part of alu- 
minum, added to Same consisting of 96 copper and 4 tin, gives 
ee a fine colo or, of remarkable homogeneity, of great hardness an 
fore free from the oxyd coating with which ordinary bronze castings 47° 
covered. The transverse strength of the castings of this al 
finds to be two and a half ti imes that of the aay cea brats 
{ bro: 
allo — Pal technische J foe cl G. J .. 
y aly s Jou xvi, pA ha: os 
Silowing sé statistics are aku y fom a paper on os Mines, Minerals 
