454 
MR. DANIELL ON A NEW REGISTER-PYROMETER 
Table XVI. 
Fusing points of alloys, derived from their expansions to 212° and 662° 
supposed equable. 
From 212° rate. 
From 662° rate. 
Brass. Copper 4s Zinc 4 
1842 
1750 
Brass. Copper -J-, Zinc y 
1672 
1910 
Bronze. Copper -pg-, Tin -rV 
1761 
1690 
Bronze. Copper -f-s Tin -p 
1773 
1534 
Bronze. Copper 4s Tin 4 
1755 
1446 
Pewter. Lead f, Tin ! 
403 
Type Metal. Lead and Antimony .... 
507 
I have not included in the foregoing Table the alloy of half copper and half 
tin, but have exhibited its expansion to the boiling point of mercury in Table 
XIV. This mixture was very hard and brittle, and resembled the speculum 
metal of reflecting telescopes. After it had been exposed to boiling mercury, 
it appeared as if it had undergone partial fusion ; it was set fast in the cavity 
of the register, and had thickened towards the lower extremity. I am inclined 
to think that it had nearly attained its melting point, but it was broken in re- 
moving it ; and I had not an opportunity of trying any further experiment 
with it. 
With regard to these alloys, the experiments are not numerous enough to 
enable us to deduce with precision the general laws by which their expansions 
and points of fusion are governed ; but enough is discernible to show that the 
subject is well worthy of further investigation. It appears 
1st. That the expansion of the compounds is not the mean of the expansions 
of the simple metals of which they are composed, but bears some proportion to 
their relative quantities. Thus we may observe that the expansion of brass 
increases with the quantity of zinc which it contains, as does bronze or bell- 
metal with the quantity of tin. 
2ndly. That the expansion of brass is in an increasing ratio to the increase 
of temperature till the quantity of zinc amounts to one half, when it seems to 
assume a decreasing rate, as we have reason to suppose is the case with pure 
zinc. On this account the melting points both of this mixture and zinc appear 
