62 
THE YOUNG SCIEKTIST.. 
Cork Stamps. 
A great many business houses make use of 
rubber stamps, which are manufactured in 
large quantities and sold at a good profit, the 
business being comparatively new. The stamps 
are made by setting up the desired words in com- 
mon type, precisely as for printing, A matrix is 
then obtained by covering the face of the type 
with moistened plaster of paris, which is al- 
lowed to remain until "set," after which this 
reverse impression is filled with the prepared 
Tubber. When the rubber filling is taken from 
Ihe plaster mold, it is a perfect fac simile of the 
iiype from which the cast was taken, and after 
being mounted on a convenient handle, is used 
for printing as a hand-stamp. 
A good substitute may be made in cork by 
•cutting the letters with a sharp penknife on the 
€nd of a smooth bottle cork, of sufficient size to 
Jiold the words intended to be printed— of course 
cutting the letters and spelling the words back- 
wards, that the impression may appear pro- 
perly. Our young readers will find this an in- 
structive amusement, and many short words 
and sentences, such as "paid," "accepted," 
"'ANSWEKED," " EECEPVED PAYMENT," " P. O. 
'BOX," etc., would prove acceptable to a father 
or a brother, for use on the office desk. 
The same ink is used as for rubber stamps, 
■and may be procured at most stationers. One 
-drop on a piece of flannel is sufficient, and will 
remain moist a long time. The cover of a 
wooden pill-box makes a good receptacle for the 
ink pad, and with this the outfit is complete. 
To Straighten Warped Woods. 
Of all the trials and vexations that beset the 
beginner, there are none more annoying than 
the tendency of wood to warp. He sends to his 
dealer for a small assortment of fine woods, and 
expects to receive them perfectly true and flat. 
Perhaps the woods are flat when they leave the 
dealer, but in transit they are very likely to 
twist out of shape, reaching their destination 
badly warped. The expressman may not be 
aware of the subtile nature of these woods, and 
in not a very gentle manner lays the package on 
a damp, cold floor. The dry wood sucks in the 
moisture on one side, swells and curls. It 
should not be a difficult matter to cure this. If 
the wood is in a large piece, the convex or hol- 
low side should be steamed or moistened a little, 
and then laid upon a dry floor, holding it down 
with a smooth, flat board, upon which weights 
are placed. When quite dry, it will be found to 
have regained its original shape. If the wood 
is in small pieces, it can be easily straightened 
hy gently steaming the convexed side over a 
tea-kettle, and then holding the other side 
towards the heat until it becomes straight, when 
it can be left in a press or under weights for a 
few hours. Almost any warped woods will 
yield under this treatment.— ie#eis' News. 
BOOK NOTICES. 
Rhymes of Science— Wise and Otherwise: 
Containing Poems by O. W. Holmes. BretHarte, 
R. W. Raymond, J. W. McQ. Rankine. and 
others. New York: Industrial Publication 
Company. 
In addition to several familiar pieces by well- 
known authors, such as the "De Sauty " of 
Holmes, the " Pliocene Skull," and the "Society 
upon the Stanislaus," by Bret^Harte, this little 
volume contains a large number of fugitive 
pieces which seem never to have found a place 
except in the pages of some periodical. Some of 
these are very good— as witness the new Version 
of "I'd be a Butterfly," and the "Tail of Long 
Ago," by some unknown author. 
The book cannot fail to afford a good deal of 
amusement. Scientific men will appreciate it for 
the burlesque which it gives of many points in 
science, and others will relish it for its fun alone. 
Imitation Mahogany.— Brush over the wood 
with common ink ; when that is dry, brush it over 
with dragon's blood mixed with methylated spirit 
in the proportion of one ounce dragon's blood to 
one-half pint of the methylated spirit. When 
that is dry, varnish with spirit varnish. 
Indestructible Ink.— The Boston Journal of 
Gheniistnj gives the following directions for pre- 
paring an indestructible writing ink: An ink that 
cannot bo erased with acids is obtained by the 
following recipe : To good gall ink add a strong 
solution of fine soluble Prussian blue in distilled 
water. This addition makes the ink, which was 
previously proof against alkalies, equally proof 
against acids, and forms a writing fluid which 
cannot be erased without destroying the paper. 
The ink writes greenish blue, but afterwards 
turns black. 
Tanning Sheepskins with the Wool On.— 
Sheepskins and the hides of some dogs make ex- 
cellent mats, rugs, etc. The following process 
has been found to succeed very well : Tack the 
skin upon a board with the flesh side out, and 
then scrape with a blunt knife ; next rub it over 
hard with pulverized chalk, until it will absorb no 
more. Then take the skin off from the board and 
cover it with pulverized alum ; double half-way 
over, with the flesh side in contact; then roll 
tight together and keep dry for three days, after 
which unfold and stretch it again on a board or 
floor, and dry in the air, and it will be ready for 
use. 
