ON THE THERMAL CONDUCTIVITIES OF CERTAIN ROCKS, 
13 
or absolute British-Association units) thus provisionally obtained, together 
with a few similar results (in the third column of the Table) found by Peclet, 
Forbes, and Sir William Thomson in rocks differing little in their description 
from those included in the present list ;— 
Provisional determinations of Thermal Conductivities of certain Rocks. 
First Experimental Results, 
Description of rock. 
Grey Aberdeen granite... 
Red Cornish serpentine... 
Calton trap-rock (first 
specimen), 
WHiINStONC....00.s0srrrreree 
Kenton sandstone.,.,,.... 
Congleton “ second grit ” 
sandstone, 
PISS Tose ke scyicasens oasis 
Alabaster” .............0000 
Sicilian white statuary- 
marble. 
Trish fossil marble , 
Devonshire red marble... 
Italian vein marble(white, 
grey veins). 
Trish green marble ,..... 
Nummulitic limestone (a 
piece of Great Pyramid 
casing-stone, presented 
by Prof. C. P. Smyth). 
Caen (building) limestone} 
WESLALES ctesreeste ttc etree sy 
Black shale (Newcastle- 
on-Tyne). 
Cannel-coal 
Soe eeeresenees 
Plaster of Paris (for cast- 
1) eRe ce eed 
Thermal conductivity 
(gramme -water-de- 
gree heat-units per 
sec., at 1° difference 
of the faces, through 
a centimetre-cube). 
00600 
00483 
00520 | -00266 
00312 | -00169 
00489 | -00689 
00462 
00392 
00412 
00559 | -0097 
00559 | -0077 
00525 | -0058 
00512 | -0047 
00507 
00433 
: 0037 
00305 | { Noss 
00384 
00178 
00161 
‘00145 
| } ‘00163 |) .op129 
Earlier observations of con 
of similar rocks, 
Description of rock. 
Calton trap-rock .,.... 
Sand of experimental 
rock, Thermometer 
Garden. 
Craigleith sandstone... 
Fine-grained grey mar- \ 
ble 
Coarse erystallino white 
marble. 
Fine-grained calcareous 
stone. 
Ditto ditto 
Coarse - grained Lias 
building-stone 
seneee 
Ordinary fine plaster 
(made up). 
Finest plaster for cast- 
ing (made up). 
| 
I 
ductivities 
Observers. 
Forbes 
and 
Thomson. 
Peclet. 
Peclet. 
Peclet. 
Geological Aspects of the Results of the Experiments. By G. A. Lenour. 
So far as these experiments have gone, they have certainly warranted the 
importance, from a geological point of view, which it was hoped they would 
have. 
Not only have the relative conductive powers for heat of a consider- 
able number of rocks been arrived at, but a distinct grouping of the various 
kinds, according to their conductivity, has sketched itself out sufficiently 
clearly, if one considers the limited amount of substances yet tested. 
K2 
