Load per sq. cm.
in grm.

Thickness in mm

Δ

Limed skin

Puered skin

0

3·45

1·78

1·67

20

3·43

1·58

1·85

40

3·33

1·43

1·90

60

3·28

1·35

1·93

80

3·22

1·23

1·99

100

3·15

1·13

2·02

120

3·08

1·08

2·00

140

3·03

1·05

1·98

160

2·95

1·01

1·94

180

2·90

·98

1·92

200

2·83

·95

1·88

300

2·73

·88

1·85

All off

2·98

—

—

380

2·61

·82

1·79

600

2·43

·76

1·67

All off

—

·76

—

Δ = difference in thickness of the skin—i.e. compression under the same load.

Fig. 11.—Apparatus for Measuring Degree of Falling

m = micrometer dial.
JJ = jaws between which the skin is placed.
b = balance-weight attached to cord passing over pulleys p p, to counterbalance weight of frame f f.
k = knife edge supporting pan and weights w.

Fig. 11 shows the apparatus[72] that was employed to obtain these results. It consists essentially of a commercial form of micrometer for measuring the thickness of leather. To one of its jaws a pan for weights is attached, by means of the frame f f, in such a manner as to secure a perfectly straight pull. The weights of the frame and pan are counterbalanced in the manner shown by a counterpoise b. The delicacy of measurement may be increased by inserting larger jaws in the form of suitably fashioned disks, but even when this is done the results are to a certain extent vitiated by the rather considerable friction of the micrometer.