1872.] Technology. 539 
water would consequently flow in the tank 4o feet lower, maintaining a con- 
stant vacuum without the aid of pumps. This objec can be accomplished in 
almost any locality by placing the condenser at the top of a building or on 
trestle work. Assuming that a vacuum has been created and provision made 
for maintaining it during the whole process, the next step will consist in the 
application of heat, which may be done most conveniently by steam-pipes 
introduced in the receiver. The length of time during which the timber must 
be subjected to the baking process will depend upon the dimensions of the 
logs, and can only be determined by experiment. It is obvious, however, that 
the circumstances are favourable to the most rapid evaporation possible; the 
temperature can be regulated at pleasure, and the removal of pressure by 
vacuum will give a very low boiling-point. As the vapours pass over they 
will be immediately condensed. Should the vacuum become vitiated by 
the escape of air from the cells, it may be improved by the use of an air-pump. 
The condition of the vacuum will be indicated by the gauges. When sufficient 
time has been allowed for the wood to dry thoroughly, cocks must be opened 
connecting the bottom of the receiver with a tank of dead oil at a lower 
level. As a vacuum exists in the receiver, the atmospheric pressure will force 
up the oil and the timber will be immersed in the fluid. When the immersion 
has continued a sufficient length of time, which also must be determined by 
careful experiment, cocks may be opened at the top of the receiver to admit 
air. The oil not absorbed will immediately flow back to the tank from which 
it was taken; the air pressing upon the exterior of the cells, which are par- 
tially filled with oil, while a vacuum exists in the interior, will force the oil 
before it, and thus coat in its progress the interior of the cells. It is probable 
that in this way a sufficient amount of dead oil may be introduced into the 
cells to prevent fermentation and decomposition while still far below the 
point of saturation, and the process may prove rapid and economical. Instead 
of admitting air in the manner proposed to expel the oil from the receiver, it 
is possible that better results may be obtained by allowing the oil to remain 
until it becomes heated by the steam coils, and the vapour collecting at the 
top expels the oil and penetrates the pores. Too much oil might be intro- 
duced by this mode of treatment, and it is probable that the introduction of 
air, followed, perhaps, by a second bath of oil to close the cells superficially 
and exclude moisture, would give the best results. All these and other 
questions that may arise can only be settled by experiment. 
In China and Japan the rice-paper plant is cultivated upon the hills and 
high-lying ground. In the autumn of each year, before the leaves fall, the 
Japanese cut off the young shoots and cut them into slips, which are tied up 
into bundles and boiled in large copper kettles or cauldrons closely shut down. 
The boiling is continued until the bark has peeled off the wood, when the 
former is carefully dried and stored away for future use. When it is required 
for paper-making it is thoroughly soaked in water for three or four hours, after 
which the brown skin is scraped off. At the same time the bark which covered 
the younger shoots is separated from the older and tougher sorts, from which 
an inferior kind of paper is made. Bark which has been kept for some years 
is only fit to make the commonest packing paper, and is manufactured with 
less care. When the bark is well cleaned and arranged in order according to 
its quality, it is again boiled until the matter separates into a filamentous 
substance. This boiling is succeeded by another operation, called washing, 
which is of great importance in the manufacture of paper. If it is not con- 
tinued long enough the paper will be of coarse quality; and if, on the other 
hand, the substance does not receive enough boiling, the paper will be very 
white, but too soft and greasy to write upon. The pulp is placed in a basket 
which will admit the water on all sides, and this is plunged into a ewer and 
stirred about with violence for some time. Then the substance is placed upon 
a smooth table and beaten with wooden rollers. After the beating an infusion 
of rice is poured upon it, and the mixture is suffered to stand until dry, when 
the substance is raised leaf by leaf in the form of paper. These leaves are 
placed between boards, and the remaining moisture gradually pressed out. 
According to another account the stem is cut into lengths of 10 or 12 inches, 
