THE YOUNG 
to make it himself he can easily do so by follow- 
ing the directions previously given. 
To make the print, place on one of the panes 
of glass several folds of tissue paper, and upon 
these the dri^d sensitized paper, with the pre- 
pared side uppermost. Upon this arrange the 
leaf or fern, singly or in a group, lay over it the 
second pane of glass, and secure the whole to- 
gether with four clips, one at each corner. Place 
the arranged glasses in the clear sunlight in a 
secure place, where the fresh air can blow ovei" 
them. If the day be clear, in about thirty 
minutes, more or less, the figures will be 
printed. Watching the paper during the pro- 
cess, you will observe the uncovered parts 
gradually changing from a yellowish tint to a 
vivid blue color, the latter deepening into black. 
When sufficiently tinted, remove the top glass 
and raise the leaf, when you will find a yellow 
outline on a deep blue ground. Now wash the 
paper in several clear waters until the yellow 
tint bleaches to a clear white ; dry with blotting 
paper, and place under a press. If the glass is 
removed too soon, the printed picture will be 
pale and washy in appearance; if exposed to 
the sunlight too long, the ground will be light, 
instead of a deep, dark color. Experience alone 
will teach the proper time of exposure. The 
printed leaves or ferns ought to be mounted on 
the left page of an album, writing on the op- 
posite page the common and botanical name, 
description, habitat, and, indeed, whatever ap- 
pears interesting in connection with the speci- 
men. 
Hard Woods. 
Chestnut and butternut are not very exten- 
sively sold for finishing, for which the better 
grades are selected, and their sale is dependent 
more on the question of taste than real superi- 
ority. The poorer stuff is used in common 
ways, and is best worked off when other woods 
used in manufacture are scarce in the dry, and 
the cull's stocks can be employed as a substitute 
on a pinch. 
Basswood is considerably sold for use in fur- 
niture. 
The black or red birch, which largely resem- 
bles cherry, figures somewhat as 9. finishing 
wood. The yellow is not valuable in the same 
way. 
Beech enters into the manufacture of chairs, 
tool handles, brewers' shavings, etc. 
Elm is made into cheap furniture. 
Yellow pine is very slow in gaining a hold 
upon popular favor. It is used by a great many 
operators who speak highly of the lumber, but 
it is far from having a boom. Generally buyers 
do not take to it kindly. What is used is mainly 
SCIENTIST. 29 
for flooring and finishing. Though the boards, 
and planks are a subject of considerable com- 
plaint on account of imperfection in manufac- 
ture, the flooring is conceded to be turned out. 
in good shape. Where high grade flooring is 
wanted, yellow pine is regarded the best and 
cheapest, but where a low or medium grade is 
desired the wood must give way to white pine> 
The latter is sold much cheaper than the yellow 
pine, for when freights are added to the price of 
the lower grades the yellow pine can hardly 
compete.— A^. W. Lumberman. 
— Scientific men in Japan are now discussing 
the possibility of utilizing the internal heat of 
the earth. At a recent meeting of the Seismologi- 
eal Society, Mr. Milne read a paper in which he 
said that the fact that there was an unlimited 
supply of energy in the interior of the earth had 
been generally overlooked, although portions of 
it crop out in countries like Japan, Iceland and 
New Zealand, in the form of hot springs, solfa- 
taras, volcanos, etc. He stated that there is an 
unlimited supply of water in hot springs within 
a radius of 100 miles around Tokio, and that the 
heat of these springs could be converted into an 
electric current and transmitted to the town. 
— The amount of water which passes through 
the roots of a plant is enormous. Dr. Lawes. of 
England, has found that an average of 2,000 
pounds of water is absorbed by a plant for every 
pound of mineral matter assimillated by it. At 
the French Agricultural Observatory at Mont- 
souris it was found that 7,702 pounds of water 
passed through the roots of the wheat crop for 
lOM pounds of grain produced, or 727 pounds for 
each pound of grain, in rich soil ; while in a very 
poor soil 1,616 pounds were passed through the 
same quantity of wheat for a product of about 
half a pound of grain, or 2,693 pounds of water 
for each pound of grain. 
— An experiment which belongs to the curiosi- 
ties of science was made quite recently at Paris 
by Drs. Eegnard and Blanehard on a stud of ten 
live crocodiles which had been presented to M.. 
Paul Bert, late Minister of Public Instruction in 
France. A crocodile was fixed on a table, and 
its upper jaw was connected to an overhead 
dynamometer or powermeter by means of a 
rope. By startling the animal with an electric 
current the downward blow of the jaw was meas- 
ured, and found to be 308 pounds at the point, 
which, considering the distance of this point 
from the masseter muscle causing the movement, 
made the total contractile force of the muscle it- 
self equivalent to 1,540 pounds. This extraor- 
dinary snapping power was that of a Saigon 
crocodile weighing only 120 pounds. An ordinary 
