ON THE CONDUCTIVE POWERS OF VARIOUS SUBSTANCES. 
845 
{b.) Blocks interchanged. 
I. 
II. 
ty 
h' 
#2- 
^2* 
r. 
212° 
165°*6 
170°'5 
56° 
k 
k 
=•30 
•33 
c 
c 
Mixed sand and clay in equal quantities. 
VIII. {a.) Two compressed blocks. 
Jh = -12ft. 
^'1^ = 4300 lbs. 
r. Jk = -I2{t. 
1^5 = 7500 lbs. 
ty 
212° 
t,. 
174°-3 
p • 
<2. 
175° 
^2’ 
l67°-5 
r. 
-=•368 
c 
- = •378 
C 
{h.) Blocks interchanged. 
I. 
11 . 
o 
• 
173° 
l66°-5 
#2* 
175° 
166°5 
r. 
58° 
-=•36 
c 
- = •379 
C 
The means from [a.) and [h.) give for I., -=-364; and for II., - = -378. 
31. Experiments to determine the effect of Discontinuity. 
Two cylindrical blocks of sandstone (freestone) were formed ft-om the same larger 
block. The experiment IX. was made to test the equality of their conductive powers. 
IX. {a.) Two blocks of sandstone. 
I. A=-166 ft. 
II. A = 
•166 ft. 
ty 
h' j 
^2’ 
r. 
211° 
l74°-7 i 173°-6 
o 
173°-8 
63° 
k .. 
- =*ol 
•51 
c 
c 
5 s 
MDCCCLVII. 
