The Sentinel. [volume] (Trenton, N.J.) 1880-1882, 1882-09-16
The Field of Science.

Electric llguI HAS DCcH iouuu " uc
very effective insect trap, and its
eventual coming into use for this pur-
pose in bug infected gardens and or
chards may be regarded as among I e
things that are possible.
The Island of Jamaica shipped last
year about 5000 bundles OF pimento
sticks for umbrella handles, each bun
die containing from 500 to 800 sticks
They are sent mainly to this country
and England, and the increase OF the
trade is rapidly thinning out the
pimentO trees.
An Antwerp firm has patented a
means of automatically playing musi-
cal instruments by pneumatic and
electromagnetic appliances. The
pneumatic arrangements IRE for sound
ing-reeds, and a sheet of card, perfo-
rated according to the tune, makes and
breaks electric contact as it travels.
The London Builder attributes The
marvellous durability of mortar in
Italy to the fact that the lime remains
in pit covered with water for two
years before it is used, whereas III
England lime is Stacked and used the
same day. Most building specifica-
tions even require new-slacked lime.
Fireproofing for wood: With three
parts of alum and one part of green
vitriol make a strong, hot solution
with water make another solution
with green vitriol in which pipe, clay
has been mixed to the consistence OF
a paint. Apply two coats of the first,
dry, and then finish with one coat
OF the last.
Out of forty-eight persons who died
of smallpox in a Southern hospital ia
one month only one was know TO
have been vaccinated. OF those wSo
recovered it was ascertained that
three-fourths had been vaccinated.
The characterization theory does not
seem to be strengthened by these fig
ures.
By experiments upon the absorption
OF radiant heat by gases K. Lechler
finds that layer of cartonic acid 917
millimetres thick absorbs 80 per cent.
of the luminous radiation. The car
bonic acid of our atmosphere is there
fore sufficient fully to account for the
atmospheric absorption of the suns
rays.
A subs titute for gutta-percha for
galvanoplastic purposes is manufac-
tured by E. Murlot, of Paris, from the
bark of birch trees. The bark is boiled
for. long time and after complete
evaporation what remains is a
mass which solidifies quickly in the
air, and which is said to possess all
the qualities of gutta percha. II mixed
with 55 per cent. of caoutchouc, this
substitute can be used advan tageously.
A correspondent of the London
Garden writes: For several years one
of sur garden beds was rendered al
most useless by the tunnellings OF ants.
Many remedies were tried, and at last
pure petroleum was poured over the
ground. After fortnight young
plants were imbedded ia il aIu a.
Tered no i'll effects, though the soil
smelt strongly of petroleum. This
happened two years ago, and the ants
have never since returned
According to the Ind4strie btntter,
metallic writing pencils consist o
alloy of lead, blsmuth and quicksllv
The ingredients vary according to I .
desired hardness of the pencils. TIL.
ordinary proportions are: Lead, 10;
bismuth so, and quicksilver, 8 parts
by weight. A larger proportion of
lead and quicksilver makes the pencil
softer and produces darker marks in
writing. The lead and bismutn are
allowed to cool somewhat, when the
quicksilver is added and the compost
too cast in proper moulds.
70 test linseed oil: An excess OF
crude nitric acid mixed with sus-
pected oil and agitated will indicate
the presence of fish oil by the dark
brown discoloration of the oil which
follows. Pure linseed oil under the
same treatment would be changed to
a sea green and finally greenish yell
low, while the acid itself becomes yell
low. Resin oil to any extent is also
indicated by adding t. one part of the
suspected oil in small phial three
parts of pure linseed oil. If the sam
pies contain resin oil the pure lin
seed floats on the top and the line of
contact is plainly visible.