DE. JOULE ON SOME THEEMO-DYNAMIC PEOPEETIES OF SOLIDS. 
113 
Remarks on the 
condition of 
the wood. 
Dried before the fire 
for several days un- 
til it could be elec- 
trified by rubbing 
with the hand, and 
retain the charge a 
long time 
Boiled in water a few 1 
minutes, then left I 
immersed in water j 
for one day j 
Weight 
of rod 
per foot 
ingrains. 
Proximate 
specific 
gravity. 
Medium of 
communica- 
tion of heat 
between the 
glass tube 
and the rod. 
Tension 
in pounds. 
Limits of tem- 
perature between 
which the expe-. 
riments were 
made. 
Linear contrac- 
tion or expansion 
per degree 
Centigrade. 
Young’s modulus of 
elasticity or length of 
rod, 1 lb. per foot, 
which would be 
extended unity by 
1 lb. tension. 
lbs. oz. 
0 0 
204-2 
•428 
Mercury ... 
f 4 5 
\ 16 5 
36-9 and 7-35 
38-5 and 8-9 
•000041666 E. 
•000045928 E. 
203732 
593-2 
1-122 
Water 
f 4 5 
\ 4 5 
33-1 and 4-38 
52 and 6-1 
•000004497 C. 
•000006455 C. 
72. The length of the wood saturated with water was 1'062 of its length in the dry 
state. In the saturated condition it broke after a tension of 17^ lbs. had been applied 
for half a minute. The specific gravity of the wood, considered apart from the air or 
water absorbed, was found to be 1'506. 
73. The following Table contains the results of experiments with a rod of deal, simi- 
lar to the last, also cut across the grain ; — 
Remarks on the condition of 
the wood. 
Weight 
of rod 
per foot 
in 
grains. 
Extreme 
length 
in 
inches. 
Medium of 
communica- 
tion of heat 
between the 
glass tube 
and the rod. 
Tension 
in 
pounds. 
Limits of tempera- 
ture between which 
the experiments 
were made. 
Linear contrac- 
tion or expansion 
per degree Centi- 
grade. 
Young’s modulus 
of elasticity or 
length of rod, 
weighing 1 lb. per 
foot, which would 
be extended unity 
by 1 lb. tension. 
Dried before a fire until it 
could be electrified by fric- 
tion 
On immersion in water, the 
wood absorbed in a few 
minutes snfi[icient moisture 
to make it weigh 243 grs. 
per foot. Its length was 
then 15'8 ; but after allow- 
ing it to rest two hours its 
length became 16-24, with- 
out receiving any additional 
waterin the interim. Twelve 
hours afterwards its length 
was 16-3, and its weight 
per foot 228-2 grs ^ 
Further immersion in water . 
Immersed several hours in 
water; specific gravity then 
was found to be -891 
Boiled in the exhausted re-' 
ceiver of an air-pump, and 
afterwards left immersed in 
water several hours ; sp. gr. 
1-143 
Dried a little by placing it a ' 
short time before a fire ... 
Dried still further - 
193-5 
228-2 
270-5 
446 
573-4 
434-4 
444-0 
358 
370 
15-625 
16-3 
16-594 
16-625 
16-7 
16-63 
16-63 
16-62 
16-62 
Mercury 
Mercury 
Mercury 
Mercury 
Water ... 
Air 
Water ... 
Air 
Water ... 
4-3 
4-3 
4-3 
4-3 
4-3 
7-3 
4-3 
4-3 
4-3 
4-3 
37-5 and 10-9 
35-1 and 10-7 
41-3 and 10-91 
43-2 and 10-95 
34-5 and 13-25 
27-2 and 12-12 
39-03 and 12-8 
34-9 and 12-7 
37-38 and 13-3 
43-8 and 15 
■000042470 E, 
■000065153 E. 
000000380 E 
000005404 C. 
000002201 C 
000001105 C 
000003159 E, 
000001561 C. 
000010390 E. 
000001356 C. 
188120 
104600 
60033 
38257 
296 18 
