FOR MEASURING THE EXPANSION OF SOLIDS. 
447 
body of the fuel, accordingly as a greater or less degree of heat was required. 
The muffle-holes were then closed until their stoppers ; all but a narrow slit, 
through which the progress of the heating and the flow of the metal could 
be observed. The equality of the heat could be very accurately ascertained 
by the uniform colour of the register as it became red ; and any irregularity 
could easily be corrected by advancing one or other end more towards the 
fuel. In this manner I succeeded in obtaining very satisfactory results ; except 
in the case of gold; and this metal requiring for its fusion rather more heat 
than I could at the time command in the air-chamber, I laid the register upon 
the fuel in the body of the furnace, and it thus became only partially melted, 
and half the bar remained in the solid state. The amount of the expansion 
indicated is therefore evidently deficient, and must be discarded from the 
table. A similar accident happened once with brass ; but this I have been 
able to rectify by subsequent trials. 
I shall now arrange the results of my experiments in two tables ; — the first 
showing, in arcs of the scale, the expansion of pure metals from 62° F. to 212°, 
662° F., and their respective melting points ; and the second exhibiting the 
expansion of certain alloys to the same points. 
The bars were in all cases of the same length of 6.5 inches. 
Table XIII. 
Showing the progressive expansion of the following pure metals to their 
melting points. 
From 62° 
to 212° 
to 662° 
to Melting Point. 
o / 
o / 
o / 
Tin 
0 55 
2 30 
Lead 
1 33 
6 17 
Zinc 
1 40 
5 50? 
8 44 
Silver 
0 59 
4 9 
13 45 
Copper 
0 45 
4 10 
16 0 
Gold 
0 35 
3 11 
(7 51 not correct) 
Cast Iron 
0 29 
2 25 
9 47 
3 M 
MDCCCXXXI. 
