The Londonderry sifter. (South Londonderry, Vt.) 1883-19??, 1889-01-17
SCIENTIFIC AND INDUSTRIAL.

Vermont factories turn out 600, 900
snowshovels per year, and New Hamp-
shire and Maine send the figures up to
100000.
A Hartford Conn betting house has
produced leather belt, double, which
is lis feet long, feet wide and half an
inch thick.
One pound of paint will cover about
four square yards of surface, first coat;
and about six square yards for each ad
ditional coat.
A test of bagging made from fiber OBJ
tair ed from Zine leaves seems to es-
tablish the fact that substitute of great
value has been found for ute.
The scheme of filing bombs with
asphyxiating gas, so that the enemy
will lie down quietly and go to sleep on
both sides after short shower of bombs,
is said to be the best that has yet been
offered in military science.
Lightning produces chemical changes
in the atmosphere. by converting por-
ton of the two gases oxygen and nitro
gen, of which it is principally composed,
into nitric acid. This acts very power
fully in destroying the exhalations which
arise from putrid vegetable and animal
matters.
A German electrician has devised an
ingenious scheme for the regulation of
dynamos The field magnet cores, in
stead of being solid, ere made of tubes,
in which solid core is inserted. This
core can be withdrawn by hand or auto
matically, and the strength of current
thus regulated.
A Birmingham (Ala) steel company
recently shipped some of their steel to a
razor company in Massachusetts,, the
latter making it into razors and sending
back word that the steel was equal in
every respect to the best Engiis cru
chile steel. Other tests, it is claimed,
proved equally satisfactory as to the
quality of the steel.
A new scheme Of utilizing the saw
dust of the Ottawa River in Canada, for
the purpose of fuel is proposed. 1t is
claimed that by system of grinding tho
refuge into uniform hneness, mixing it
with the refuge gas tar from the gas
house and COMPRISING the substance
into cakes, fuel can be made in every
way superior to soft coal for open fires.
Duringa discussion of the "lightning-
rod question at the last meeting of the
British Association, it was stated that
where there are special corroding
agencies at work copper is to be preferred
to iron az being less easily oxidized, but
that in ordinary cases equally good Sc
curity can be obtained, at much less ex-
pense, with iron. The question whether
the rods really afforded any security was
not considered.
An English electrician has invented q
material which he calls alterion for the
prevention of corrosion in boilers. The
| interior is quoted with this and currents
of electricity are passed through the
boiler and from time 10 time reversed.
The formation of scale is prevented by a
layer of hydrogen gas, which is deposited
upon the inner surface of the boiler. The
reversed currents reforms the hydrogen
into pure water, thin layer of pure
water being thus kept all around the
boiler.
A chimney 1872 feet high settled until
its top was three feet two inches out OF
the perpendicular. This was at the
works OF Matthews & Sons, in loucester-
shire, England. A course of bricks was
taken out for tive-eighths of the circum-
ference and replaced by course, enc
and five eighths inches less in height. As
fast as the cut was made the new course
was laid and iron wedges were driven in
above it. When all was IN place. tn
wedges were driven out, and the ch m
new came back to within an inch or tw.
of the perpendicular.