138 
THE YOUNG SCIENTIST. 
To polish a surface thus prepared, not 
being hard wood and not in the lathe, take 
a ball of cotton wool saturated with 
methylated French polish ; cover it with a 
fold of linen cloth ; on the linen cover put 
with the tip of the finger a drop or two of 
raw refined linseed oil (not " boiled oil ") ; 
get on a good body of varnish by rubbing 
always one way with circular strokes : be 
very careful to go over all the ground each 
time you work round the surface ; and do 
not go over the same spot twice before you 
have gone over all. The longer this is 
done the better. Never mind the smears, 
which, though they look queer, are the 
very appearance you want at this stage. 
Having got on a good body, leave your 
work and take to another piece. It is 
good to leave it, if convenient, even for a 
day or two. By the way, shut all doors 
and windows before you begin. You can't 
do French polishing in a draft or in a very 
cold room. 
When you resume work, use a mixture 
of half methylated spirit, or less than half 
of the spirit when you commence, and put 
now as little as possible on the wood, cov- 
ering it with more than one fold of fine 
linen or cambric. Very little oil, as before 
— only just enough to prevent the rubber 
from sticking to the work; go over it 
lightly, with an easy gentle touch, in cir- 
cular strokes, all one way. Never mind 
the smears. When it comes to look some- 
thing like a good result, which it soon 
will, you may take out the smears by rub- 
bing up and down with a mere trace of 
spirit on wool well covered with the linen, 
but avoid going over the same place twice, 
and be very light and gentle, or you will 
remove your polish. Finally, rub it well 
with a clean wash leather (carefully folded, 
so as to have no hard crease which will 
scratch), or an old silk handkerchief, 
breathing on the work occasionally. 
Boxwood, ebony, cocus, etc., may be 
rapidly polished in the lathe. At first get 
a body on of polish, and this can be done 
without using any oil. The work must 
not be turned round rapidly, but the pul- 
• ley of the lathe moved slowly by hand ; 
then use your rubber with a drop of oil, 
V and finally, the polish thinned with spirit. 
If either on flat or turned work you re- 
quire a very superior polish, you may re- 
move nearly all the first coat with fine 
sandpaper, and put it on again, which will 
not take long, the pores being all filled. 
Kemember that throughout, the oil is only 
used to prevent the rubber from sticking, 
and it has to be got out afterwards with 
the spirit ; so never use more than neces- 
sary. 
In the lathe, when you come to the wash 
leathers, the work may be driven rapidly. 
A bit of ebony can be polished in five or 
six minutes to such a surface that small 
print can be easily read in it as in a mir- 
ror. Don't use your rubbers when they 
get hard and dry, but nevertheless stick to 
an old one as long as you can, and if you 
have to put them by, keep them in a tin 
box tightly covered. 
A Lesson in Hydrostatics. 
"OEGINNEES in science are often fright- 
^ ened with hard words and think that 
because a subject has a long, hard name 
like hydrostatics, therefore, it can have no 
relation to ordinary everyday occupations. 
But just as the countryman in the French 
play had talked prose all his life without 
knowing it, so every good housekeeper 
concerns herself with hydraulics, hydro- 
statics, pneumatics, etc., without being 
aware of the fact. It will not be difficult 
to find many illustrations of hydrostatics 
in ordinary household work. But first of 
all let us examine the engraving on the 
opposite page, and learn what it teaches 
us. 
The experiment which this figure illus- 
trates is one that it is not difficult to re- 
X^eat. A good stout barrel, known to be 
watertight, has a long pipe secured to its 
head as shown in the figure. The cask 
may now be filled with water until the 
liquid stands two or three feet high in the 
tube, and it will then be easy to see whether 
or not the cask leaks. If everything is 
sound, pour another pitcherful of water 
into the tube, and unless the cask is very 
much stronger than those usually made, 
the hoops will burst and the water pour 
out of the openings between the staves. 
The astonishing feature of this experi- 
ment is the very small weight of water that 
