Description of Wood.

Spec, grav.

Cohesion of a sq. inch.

lbs.

Acacia...............

.85

16,000 +

Apple.................

.71

19,500

Ash....................

.84

16,700

" .................

.78

19,600

Beech................

.72

22,200

Birch......

.64

15,000-

Box..................

.99

15,500-

Cane.................

.40

6,300

Cedar..................

.54

11,400

Chestnut (Horse)

.61

12,100-

,, (Sweet)

.61

10,500-

Damson................

.79

14,000

Deal, Norway) spruce .. ..

.34

18,100+

" "...........

..

17,600+

" Christiana

.46

12,400

" " .....

.46

12,300

" " ......

.46

14,000

,, English .....

.47

7,000

Elder......

.73

15,000

Elm .................

.69

14,400

Hawthorn..........

.91

10,700

" ............

...

9,200

Hazel.................

.86

18,000 +

Holly......

.76

16,000

Hornbeam..........

.82

20,240+

Laburnam..........

.92

10,500

Lancewood.........

1.01

23,400+

Description of Wood.

Spec, grav.

Cohesion of a sq. inch.

lbs.

Larch ...............

.57

8,900

Lignum vitae ..

1.22

11,800

Lime-tree ...........

.76

23,500+

Mahogany.........

.87

21,800+

" ..........

.80

16,500

Maple ............

.66

17,400

Mulberry..........

.66

10,600

Oak, English ..

.70

19,800+

" " ......

.76

15,000

" " old

.76

14,000

" pile out of river Cam ..

.61

4,500

" black bog

.67

7,700-

" Hamboro...

.66

16,300+

" " .........

.66

14,000

Pine, Peters burgh .. ..

.55

13,300-

" Norway ....

.59

12,400-

" " .......

.66

14,300

" Petersburgh

.55

13,100+

Plane ................

.64

11,700-

Poplar .. ..

.36

7,200-

Sally .. ..

.70

18,600+

Sycamore ........

.69

13,000

Teak, old ........

.53

8,200

Walnut ...........

.59

7,800

Willow ............

.39

14,000

Yew ..............

.79

8,000

Note. - The specimens in the above Table varied in length from 9 to 13 inches, and were reduced in a lathe for a small part of the length, in the middle, to near half an inch in diameter, leaving at each end something more in general than 4 inches long, and about 11/10 inch in diameter, for the purpose of being fastened into cast-iron boxes, made of sufficient strength to bear a strain of several tons weight. The wood thus prepared was secured at each end in one of these iron boxes, and suspended vertically at the end of a lever of suitable strength to bear a force of 5000 or 6000 lbs., the operating strain being produced by the gradual and slow motion of weights of 200 lbs. each, resting occasionally at intervals of 5, 10, 15, or 20 minutes, and sometimes for hours.

In the course of these experiments Mr. Bevan occasionally found part of the larger ends drawn out in a cylindrical shape when the lateral adhesion was less than the longitudinal cohesion; in these cases the number of pounds expressive of the cohesion is short of what is due to