102 DE. JOULE ON SOME THEEMO-DINAMC PEOPEEIIES 01 SOLIDS. 
34. In addition to the above, my own experience has led me 
nf inrUa rubber softened by warmth, may be exposed to the zero of FAHEE^HE 
losJg its phahiUty; but that a few days rest at a tempera- 
oVvixr ttnnvp tbp freezins-point will cause it to become rigid. 
end. ot d piddd of oloodc iudio.rubtet, about Atba of an iath square, um 
“■"S “ ■»* -“ « r:».:f£‘:4 o ." - » *: 
= rEr-; -.t a“-;bt7.cr.i^“= 
;EroE.rS“b;~— 
Stretching weight 
in pounds. 
Length of rubber in inches 
Deflection of 
Thermal eflFect 
indicated by 
deflection. 
When stretched. 
After weight 
was removed. 
thermo-multiplier. 
0 
2 
4 
6 
8 
10 
12 
14 
16 
18 
0-59 
0-67 
0-77 
0- 94 
1- 13 
1-45 
1- 7S 
Not observed. 
2*14 
2- 36 
0-69 
Not observed. 
Not observed. 
Not observed. 
Not observed. 
0-71 
0 - 9 
Not observed. 
Not observed. 
1 - 02 
° 6 
0 
— 1 
11 
32 
1 15 
2 47 
4 50 
5 55 
6 45 
O 
0 
0 
— 0-002 
0-020 
0-059 
0-139 
0-370 
0 537 
0-657 
0-750 
• T 1 1 1 
36. The low temperature (aDoui o 
experiments were tried considerably interfered with the perfection of 
the elasticity of the india-rubber, which in consequence became gia- 
dually elongated on the removal of successively mcreasing weights. 
This circumstance no doubt interferes slightly mth the absolii e 
quantity of thermal effect recorded in the last column of the Table. 
StiU the essential characteristics of the phenomena are plainly indi- 
cated viz. that little heat, or even a reverse effect, is produced by 
moderate stretching weights, but that after a certain weig it is 
reached, a rapid increase of thermal effect takes place. 
37 The same piece of rubber was afterwards immersed in wa er in 
the manner represented by the adjoining sketch. A wire attached 
to the rubber at the upper extremity was made fast, and anothei 
Wii-e affixed to the lower end passed through a cork in the glass tube 
and being bent into a hook, supported a scale for weig is. i 
temperature of the water in the tube was kept iinitorm by constan 
