New-York tribune., 1879-10-18
SCIENCE tOR TIE PEOPLE.

SCIENCE tOR THE PEOPLE.
INSECTS IN BooKs.--At the recent meeting OIL
the Brush Scientific Association. Professor "est"oo"
reada paper interesting TO ali possessing library h'
described the life history Of the various insects wch at
tack books and suggested some remedies. lhe cater
pilars OF the moIh Aglossa pingmnais and also OF
snec,s ar Depressars often njure books by spinning
their webs between the volumes. and gDawing small
porton of the paper with which to form their cOcoons
small mite. Cheyetus eruditus Is also found occa-
sionally in books kept damp situations. where 1t
gnaws the paper. very minute beetle Hypothenemus
eruditus westwood forms its tiny burrows within the
binding of books The small silvery insects Qepsma
saccharna found in closets and oupDOards whore pro-
visions kept also feed on paper. curious example
of its work exhibited in framed and glazed print,
OF which the plain portion eaten, whilst the parts
covered by the printing ink untouched The au-
thor has assured that the fact has been OBJ
served India where OF the Government records
had been injured the manner. The habit of the
Leplsme had not been previously recorded. The white
ants Uermtidgl constant source of ANNOYANCE IN
hot and climates, eating al kinds OF objects OF
vegetable origin, of which several instances were re-
corded by Dr. Hagen, including the destruction Of
stock Of bibles and prayerbooks COckroaches iBlatta
orientasl, are also equally destructive to books when
they fall in their way. But II Is the Deathwatches
(Anobium pernax and striatuml, which do the great
est injury. gnawing and burrOwng not only In ana
through the bindings, hut also entirely through the
volume and Instances have been recorded where not
fewer than twentyseven folio volumes placed together
on a bookshelf have been cleany drilled through by
the larva Of this beetle that string might be run
through the hole III de by them and the volumes raised
by string. The remedies against the attacks or the
Anobum upon objects OF carved wood must necessarily
he OF daeren character from those used against the
book worms which are the larvn OF the Anooe. In
the former case saturatiOn with chloride OF mercury
dissolved in Inethy spirits OF wire other analo
gous fluid has been found to be efficient But win re-
rpdzation, nnd experiments were recorded in which
objects attacked by the Anobld had been placed III =
large glass case, made alright as possible ana
small saucers with pieces OF sponge saturated with car
boc acid placed at the bottom Of the case and ON
tbe of the author had been found sue
cessiu 10 place the infected volumes IN the Bodeian
Library closed box, with quantity OF benzne III
saucer at the bottom strong infusion OF colOcynth
ana quassi choroform spirits Of turpenne, expressed
es O aPeTG sGeT on large
scale may also be adopted y having room made as
ar-ight possible. burning birthstone III II, or nlng
the with fumes OF prussc acid or benzne Dr
under hcllgass OF an ar-pump and extracting the
the Larvae would be killed during an hours exhaus
ton.
DEPTHS OF LAKEs.-In Baikal (Siberia)
soundiugs have been obtained which. for a lake. are
truly astonishing II the upper part the depth 1907
metres about the height of Mount Etna), but down
ward the bottom constantly descenis, and the OPP
poste end. distance OF some $50 miles the depth
amounts TO 1896 metres The measurement far ex-
cecls ANYTHING found In the Mediterranean Sea,
which In its deepest part has only 2l97 metres OF water
How such extraordinary depression as that OF
Bakal could have occurred IN the midst OF continent
is a problem which greatly puzzles geoogsts, but the
generally accepted idea Is that II was the result of some
volcanic eruption IN past ages, and subsequent sunsi-
lakes centre of NeNzealand are equally remark
able IA point of depth Tue extreme depths OF the
T,upo and Waikar LAX, in the North, and Lake Wa
katIpu in the SOUTH have never been fathOmed They
are known to be very far below the sea-leyel
smvERING MIRRoRs.-The plan Of coating
mirrors with thin film Of silver. though superior TO the
old amalg gamatng process, has some drawbacks The
ordinary treatment follows The glass Is laid on
horizontal table Of cast-ron covered with woollen
cloth heated TO 40 deg. Centig. t10l deg. Fahr)
On tho glass; previously we'll cleaned poured sue
cessivcly solution Of ararc acid. and then another
Of amnonlacal nitrate OF silver. Under the influence
of the heat the organic acid reduces the metallic SALT
and after about twenty minutes the silver is deposited
Oh the glass in adhercnt layers the whole operation
does not occupy than hour. The mirror is then
dried and the metal covered with varnish sufficient to
protect from friction and the action OF phnr vapors
which blacken IL. But silver deposited IN this way
often unpleasant yellOwish reflection NJ LenOir,
Of Paris turned his attention to discovering process
which would obviate this drawback. lie mas succeeded
by the following means. The glass. once svercd. is
subjected to the action OF dilute solution Of the
double cyanide Of mercury aud potassium. when an
amalgsm OF white and brilliant silver Is formed adher-
ing strongly the glass. To facilitate the operation
aud utilize all the silver employed. NJ. Lcnoir. by a
Improvement sprinkes the glass at The moment
the mercural solution Is applied with VERY fine powder
Znc which preclpitates tie mercury aud regulates
the amagamation. Mirrors thus treated longer gye
II is SAID, the ycllowish magc of the silver used alone
but the white and br liant rejection OF the old process
without the cnanajion OF Vhpors which would DC ln-
uIous the men employed upon the operation.
ECONOMICAL LAMPs.-According to German
trade paper II new kerosene aud spirit lamp has
invented in which the wick made entirely Of glass
Several advantages claimed for it, The flame clings
closely the wick, that lighted lamps may be car
red about without fear Of their being extngushad by
sudden draughts moreover, no sparks are liberated
from It, With an equal of this wick turned up
much hr ster aud clearer light Is obtained than where
cotton are used The smoking Is greatly reduced.
and at least 10 per of oil saved There scarcely
any waste Of wick itself and the Troublesome
ming and emitting to which lamp burners are accus-
toned rr altogether needless, for no portion Of T.
bonzcd. Used IN spirit lamps IL greatly Increases the
heat OF the nc. and hnay 1t claimed that can be
produced aud SOo at a cheap rate.
ELECTRICITY AS AN ORNAMENT.-M. Trouv6, |
who has recently utilized electricity for many novel
PURPOSES has applied it trnkets aud articles OF
ornament. For instance, OF two scarf-pins his a
deaths-head gold enamel. with diamond eyes and
arcuated Jaw the other has rabbit seated upright
"A box with little bell before II, to be struck with
tworodS held in the animals fOrcpaws An invisible wire
connects these objects with small hermeticaly closed
battery the ebonite which about the size OF
cigarette kept in the waiscoat pocket aud acts
only when TUNED horizontally inverted When a per-
son looks al pin the owner, slipping finger into his
uocket moves tue battery, whcreupon the deatshead
roll. lts ewes gruds ts teeth, the little rabbit
heals the bell with it, rods lrd kind OF ornament
is n small bird ST with diamOn To be- fixed IN lady's
hair and tie wings OF winch can be set motion elec
tTicaliy.
RELIGIOUS INTELLIGENCE.
Dr. Edward Beecher will celebrate his golden |
wedding III Brookly week from Monday.