of Edinburgh, Session 1884 - 85 . 
315 
Vulcanite . — The first specimen employed was a parallelepiped, 
two centimetres long and one square centimetre in section. The 
following is a table of the results : — 
Temp. 
in 
Degrees 
Centi- 
grade. 
Thermal Effect on 
applying 
Pressure. 
Thermal Effect on relieving 
Pressure. 
Pressure. 
Deflec- 
tion. 
Temp. 
Raised. 
Rise 
per Ton. 
Pressure. 
Deflec- 
tion. 
Temp. 
Lowered. 
Fall 
per Ton. 
16° 
26 
1-66 
0° -35' 
0°-30 
22-4 
1-4 
0° '3 
0°-30 
16° ’3 
45-2 
2 '68 
0°-56 
0°-28 
41-6 
2-5 
0°-52 
0°-28 
16° -6 
67 
4-0 
0°-83 
0°-28 
61 
3-7 
0°-79 
0°-28 
We also tested the vulcanite used to protect the “ Challenger ” 
Expedition thermometers. The specimen employed was a cube of 
one centimetre. The following table shows slightly greater results 
than were obtained with the first specimen : — 
Temp. 
in 
Degrees 
Centi- 
grade. 
Thermal Effect on applying Pressure. 
Thermal Effect on relieving Pressure. 
Pressure. 
Deflec- 
tion. 
Temp. 
Raised. 
Rise 
per Ton. 
Pressure. 
Deflec- 
tion. 
Temp. 
Lowered. 
Fall 
per Ton. 
16°'6 
25 
1-6 
0°'37 
0° '33 
22-5 
1-4 
0°-33 
0 o> 33 
16° 
45-6 
272 
0°-63 
0°-31 
45 
2-86 
0°-66 
0°-33 
16° -3 
66 
3-6 
0°-83 
0°*28 
55 
3-4 
0°-79 
0°‘32 
Glass . — The specimen employed was a cylinder of common lead 
glass, two centimetres long and one in diameter. The bore into 
which the junction fitted was filled with powdered glass, so that 
as little water as possible might intervene between the junction and 
the glass. The following is a table of the results : — 
Temp. 
in 
Degrees 
Centi- 
grade. 
Thermal Effect on applying ! 
Pressure. 
Thermal Effect on relieving : 
Pressure. 
Pressure. 
Deflec- 
tion. 
Temp. 
Praised. 
Rise 
per Ton. 
Pressure. 
Deflec- 
tion. 
Temp. 
Lowered. 
Fall 
per Ton. 
14°-6 
24 
0-6 
0° T3 
0°'12 
24 
0-64 
0°-13 
0°12 
15° 
49 
1-35 
0°-28 
o 
o 
CO 
47 
l°-45 
0° ’3 
0°-14 
66-4 
1-87 
0°-39 
0°T3 
65-2 
1-97 
0°-41 
0°14 
58-4 
1*66 
op 
© 
CO 
o 
O 
58-6 
1-74 
0 o< 36 
0°-14 
VOL. XIII. T 
