Notes on the Properties of Wood. 113 
BYOMWOOd) 6..4000.5.4. ‘201 Mew Munem 0807 
Greenheart.......-. 323 L200 Blin* eh di adeeb 0'800 
Sabicue wood ...... I‘100 plete oh LOGE. 0'733 
Praziowood. .v...0... I'100 | yg an Pepeeueae curser eae 0°657 
PEAY Oils iii enews I‘080 ime y RAL a ae 0604. 
i es Lat ret eae I'050 Cy piiess GURe A 0°598 
SC) CY eee ee 0'950 CaO Sa ieid rede o'561 
Lilac or pipe tree... 0°903 Poplar (silver) ...... 0529 
0 ne 0885 ASSafras wet 0'482 
eee A. we’ 0852 Poplar (common ... 0°383 
PMC acini seeded ss 0845 Cork: oN6. peas 0'240 
The weight of water for the above is taken at 1°000. 
Experience has shown that the time when trees are 
felled has much influence upon the condition of the wood. 
A trial was made in Germany with four pieces of oak cut 
down in December, January, February, and March. A tin 
ring was fixed at one end of each of the four pieces. These 
rings were filled each with two quarts of water, and it 
proved that the piece of wood cut in December did not 
permit any water to pass through its pores. The January 
wood, after forty-eight hours, passed.a few drops. During 
the same time the entire quantity had run through the 
February wood, and the water had passed through the 
March wood within two hours and a half. This accounts 
for the reason that barrels of which the wood was felled in 
February or March will lose within a year as much as eight 
quarts of water, whilst others lose hardly any at all. One 
should suppose that wood would absorb salt water more 
easily than fresh water, because the pressure of the former 
being so much higher. Still this is not the case, and Mr. 
Duhamel has proved this by an experiment. He took two 
pieces of oak from the same plank, weighing each 5lbs. 
During eleven months the one was exposed to salt water, 
and increased only by 2°141]bs. in weight, whilst the other, 
put into fresh water, increased by 4'141Ibs. 
Wood which lies in the atmosphere will constantly vary 
in weight, which depends upon the wet or dry season, and 
as the action is accordingly, we find the wood in its section 
in a regular hygrometrical action. 
If we attempt to abstract all moisture by heat from the 
wood, we must not forget that at the same time we destroy 
its nature, that is the physical condition of the wood, by 
which it becomes very liable to break. Almost the same 
influence has too much hot oil upon wood. Through this 
