THE YOUNG SCIENTIST. 
131 
thus curving the sides of this wedge, is to 
render it greatly more obtuse. Moreover, 
Fig. 1. Fig. 2. Fig. 3. 
when we turn the screwdriver, the tendency 
to slip out of the nick is just in proportion 
to the obtuseness or bluntness of the wedge, 
and therefore this form is the very worst 
that can be chosen. In the hands of most 
good workmen, therefore, we find that the 
screwdriver ends in a wedge of which the 
sides are perfectly straight, like Fig. 2. This 
is a very good form, but is not equal to 
Fig. 3, in which the sides of the wedge 
are curves, but with the concave sides turned 
outwards. In this way we lessen the ob- 
tuseness of the wedge at the extreme point, 
and produce a turnscrew which may be kept 
in the nick by the least possible pressure 
endwise. To grind a screwdriver into this 
form, it is necessary to use a very small 
grindstone, and many of the artificial 
stones found in market answer admirably. 
Amateurs would find it to their advantage 
to keep one of these small grindstones for 
this and similar purposes, as it can be run 
in the lathe with very little trouble. 
The Effect of Politeness. 
4 BKAVE, active, intelligent terrior, 
belonging to a lady friend, one day 
discovered a monkey belonging to an itin- 
erant organ-grinder, seated upon the bank 
within the grounds, and at once made a 
dash for him. The monkey, who was at- 
tired in jacket and hat, awaited the onset 
with such undisturbed tranquility that the 
dog halted within a few feet of him to re- 
connoitre. Both animals took a long, 
steady stare at each other, but the dog evi- 
dently was recovering from his surprise, 
and about to make a spring for the intruder. 
At this critical juncture the monkey, who 
had remained perfectly quiet hitherto, 
raised his paw and graceful ly saluted by 
lifting his hat. The effect was magical; the 
dog's head and tail dropped, and he sneaked 
off and entered the house, refusing to leave 
it till he was satisfied that his polite but 
mysterious guest had departed. His whole 
demeanor showed that he felt the monkey 
was something ''uncanny," and not to be 
meddled with. — Nature. 
To Remove Tight Stoppers. 
To remove glass stoppers when tightly fixed, 
it has been recommended to apply a cloth wet 
in hot water. This is an inconvenient and fre- 
quently unsuccessful method. The great ob- 
ject is to expand the neck of the bottle so as 
to loosen it on the stopper. If, however, the 
latter be heated and expanded equally with the 
former, the desired effect is not produced; and 
this is often the case in applying hot water. 
By holding the neck of the bottle about half 
an inch above the flame of a lamp or candle, 
for a few seconds, we have never failed in the 
most obstinate cases. The hands should be 
wrapped in a towel, and great care should be 
taken not to let the flame touch the glass, as 
this might cause it to crack. The bottle should 
be kept rapidly turning during the operation, 
so as to bring all parts of the neck equally 
under the influence of the heat, when it will 
be rapidly expanded, and the stopper may be 
withdrawn by a steady pull and twist. Follow- 
ing this plan, we have never failed once out of 
hundreds of attempts. When the bottle con- 
tains alcohol, benzine, ether, or similar in- 
flammable liquids, great care must be taken 
lest the stopper should come out suddenly, and 
the contents of the bottle take fire. — Amaimr''s 
Handbook. 
Preserving the Colors of Pressed Plants. 
The following process is said by the London 
Chemist and Druggist to give very excellent re- 
sults: Dissolve one part of salicylic acid in 600 
parts of alcohol, and heat the solution to the 
boiling point in an evaporating dish. Draw the 
plant slowly through the liquid, wave gently in 
the air to get rid of superfluous moisture, and 
dry between folds of blotting-paper several 
times repeated. In this manner the plants dry 
rapidly, which is a great gain, and they thus 
furnish specimens of superior beauty. 
