150 
MR. RENNIE’S EXPERIMENTS ON THE FRICTION AND 
The apparatus employed in performing the experiments on the friction of 
attrition, Plate IV, consists simply of a strong table accurately made and ad- 
justed, and provided with a platform capable of being elevated to any angle 
within thirty degrees, as shown by the graduated arc. The substances tried 
were placed on the platform and in the sliding block above, to which the scale 
and weights for bringing the substances into closer contact were suspended : 
a cord going over a pulley was attached to the sliding block, which received its 
motion from weights put into the moving scale. The different phenomena were 
then accurately recorded, as appears by the accompanying Tables, and the 
conclusions derived from them. 
Table I. 
Experiments on the Friction of 3 square inches surface with Cloth. 
Weight on 
surface. 
Weight required 
to move it. 
Proportion. 
Weight on 
surface. 
Weight required 
to move it. 
Proportion. 
Black Single Kerseymere 
No. 1 
Superfine Blue. No. 2 
lbs. 
lbs. 
OZ. 
lbs. 
lbs. 
oz. 
1 
1 
6 
1 
1 
3 
o 
2 
4 
2 
2 
12 
5 
4 
2 
1 
21 
5 
5 
3 
10 
6 
4 
1 
60 
10 
8 
4 
1 
21 
20 
9 
13 
2 
03 
20 
12 
11 
1 
57 
28 
13 
2 
2 
13 
28 
15 
5 
1 
82 
56 
20 
11 
2 
70 
56 
22 
11 
2 
47 
Drab Milled Kerseymere. 
No. 
3. 
Drab Kersey Hunter. No. 4. 
lbs. 
lbs. 
OZ. 
lbs. 
lbs. 
OZ. 
1 
1 
11 
1 
1 
5 
2 
2 
11 
2 
1 
15 
1 
03 
5 
5 
3 
5 
3 
8 
1 
43 
10 
took 2£ lbs. in 
tion to start it 
addi- 
I 7 
13 
1 
28 
10 
5 
4 
1 
90 
10 
20 
after remain* 12 hrs. 
it took to start it 
}l2 
12 
10 
11 
1 
57 
20 
28 
8 
10 
11 
0 
2 
2 
30 
80 
28 
16 
7 
1 
70 
56 
19 
3 
2 
92 
56 
25 
3 
2 
22 
Strong Drab. 
No. 
5. 
lbs. 
lbs. 
oz. 
1 
0 
15 
1 
06 
2 
1 
8 
1 
33 
5 
3 
2 
1 
60 
10 
4 
11 
2 
13 
20 
7 
11 
2 
60 
28 
9 
12 
2 
87 
56 
17 
14 
3 
13 
