The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1886-12-04
Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.
SAVING STEAM

A considerable advance in engineering science
is claimed for the Merchant engine, which is said
to represent a practical solution of the difficult
problem of returning to the boiler otherwise wasted
steam. Put to test recently by responsible and
disinterested British engineers, the fuel used is
reported to have been but trihe more than half
pound of Welsh coal per indicated horsepower
per hour, the economy being SO great that it is
calculated such engines would save $4,000 daily
for one steamship company alone. The new con-
denser also makes it possible, it is affirmed, to
build locomotives to run 1000 miles without o
fresh supply of water.
BULLETS IN THE BRAIN.
By a curious coincidence, two persons with bull
let-wounds in the head were received at the Lon
don Hospital on the same day-June 10th. More
remarkable is the fact that, though in each case
the bullet was driven into the brain too deeply
for extraction, both patients have been discharg
ed conTalescent. These marvellous recoyeries
from what, few years ago, would have meant
certain death, illustrate the effects of superior
surgical skill and the modern antiseptic method
of treating wounds.
ANCIENT DENTISTRY.
In many skulls from Roman and Etruscan
tombs DIR. ,Marter of Rome has discovered inter-
esting specimens of ancient dentistry and artif-
cial teeth. These latter are in most eases carved
out of the teeth of some large animal, and in many
instances are fastened to the natural teeth by
DanUS Oh ROIu.N NU uiicu tcctu udso ueou uio-
covered. The skulls examined date back as far
as the sixth century B. c., and prove that tooth
ache and the. art of dentistry are by no means
modern institutions.
A NOVEL INDUSTRY.
Few persons on visiting a museum consider
that such objects as skeletons require certain
fitting for exhibition. Yet the preparation of
skeletons for the market constitutes distinct in
dustry, to which large mandatory in the sub
urbs of Paris is devoted. Corpses are supplied
from dissecting rooms and hospitals. On its de-
livery the raw material is boiled for days in
cauldron, and the grease which rises to the sur
face is skinned off and sold. The bones are care
fully cleaned and bleached in the sun, and finally
assorted and converted into articulated skeletons.
The preparation of frogs, lizards and various
reptiles occupies separate department.
DURATION OF INFEcTIoUsNEss.
The duration of the infectious stages of various
diseases is thus given by DIR. I. +. Pearse, an
English physician. Measles from the second day
of the disease, for three weeks smallpox from
the first day, for four weeks; scarlet fever from
the fourth day, for seven weeks mumps from the
second day, for three weeks; diphtheria from the
first day for three weeks. The incubation periods
or intervals occurring between exposure to lnfec-
ton and the first symptoms, are as fohows.-
Whooping cough, fourteen days; mumps, elgh-
teen days measles, ten days; smallpox, twelve
days; scarlet fever three days; diphtheria, four
teen days.
THE WORLDS GREATEST DESERT.
One-half of the earth's solid surface is buried
in the abysmal regions of the ocean, and exists as
undulating plains beneath watery covering from
two to five miles thick. On this land at the bot
tom of the deep sea- the director of the Challenger
publications tells us the conditions presented
are most uniform. The temperature, near the
freezing point of fresh-water, does not exceed
seven degrees in range, and is constant through
out the year in any locality. Sunlight and plant
life are absent and, although animals OF the large
types are present, there is no great variety OF
form or abundance of individuals. Change OF
any kind is exceedingly slow. At the greatest
depths the deposits are chiefly AIRED clay mixed
with fragments of volcanic matter, remains OF
deep sea animals, cosmic dust, manganese-iron
nodules and zeolitic crystals. No analogous de-
posts have been traced on dry land, although the
continents are mainly made up of rocks which
must have formed under the sea near the coasts.
Throughout all geological time the deposits of the
continent bordering waters appear to have been
forced up into dry land through the contraction
of the earth, while the abysmal regions have re-
manned the most permanent areas of the earth
surface.
GLASS FOR RAILWAYS.
A glass as hard as any cast metal, and not more
expensive than cast iron, has been produced by
Mr.. F. Siemens of Dresden. Experiments are
being made to determine whether it can be used
for rails on railways. Specimens OF this hard
glass have been found suitable for milstones and
railway sIeepers. An important advantage OF
the glass is its transparency, as flaws can be de-
tected before it is put to practical use.
MISCELLANEOUS.
Italian physicians are very successfully treat
ing lockjaw from wounds by keeping the patient
in state of perfect rest in room specially pre-
pared for preserving absolute silence. One prac-
titioner reports recovery in four out of every five
cases.
Some photographs of recent thunderstorm IN
France are said to indicate that the normal form
of lightning discharges between the clouds and
tbs eth is that of an irregular spiral
On opening a black snake, captured in Tas-
mania, the unprecedented number Of log young
ones was found, the greatest number previously
recorded having been 80. The snake measured
four feet three inches in length.
Two cases of hydrophobia in camels are report
ed from Algeria. The animals were not known
to have been bitten, but had grazed in q pasture
which had fed a rabid horse.
A list of over forty new chemical elements
whose discovery has been announced by eminent
chemists since 1877, has been prepared by Prof.
H. c. Bolton. Nine of the supposed new elements
have been detected this year by Crookes.