The Washington union., 1858-02-04
rur AIRS AND PRACTICAL SCIENCE.
COMPLIED roa rnr wAsuSeroN UNION.

Sale from Glf Tasr.--Ihe Academy OF Science in New
Orleans has received paper purporting 10 demonstrate
the fact that the waters of the Gulf ON the borders oil
southwestern Louisiana and thence to Texas are the
safest that have been submitted scientific tests and
that by the process OF evaporation IN tanks salt OF s
peor quality equal TO that OF Turks Island may be OBJ
tanned
Literary Society has been established at Jerusalem
and James Finn the British eonsu elected president At
its first meeting which held in November DR. Roth
OF Munich described his researches and success in
search of the true Tyran purple dye. When he Or
Roth first to Palestine he found at Jaa the Papu
paula the snail of which is used by native Christians
here for food during the ts In puncturng these there
Issued greenish liquor which in the sunshine changed
to purple and this by washing increased in brillancy
Comparing this with the left by the ancens 1t
Is clearly their blue purple for they had blue purple
deep purple, and red purple,
Ossiam Iridium is more dense than gold The method
adopted for its separation the ST. Petersburgh mint
from Russia gold is TO alloy it with three parts of silver,
melt the metal in large black lead crucibes, and keep
them at rest for some time during which the iridium
grannes sink to the bottom The upper portion of the
gold then dipped out to within inch of the bottom
of the crucble and into ingots The small portion
of the metal left at the bottom contains the greater por
ton OF the iridium, which is separated in the wet
way by NEUTRALITY-SUSPICIOUS. acid which dssolves the
gold but does not act the iridium ganues Some of
our California gold contains iridium.
Strength of Iron for Boilers, Pipes Sc.-s Some expert
ments of considerable practical Importance have been
made, with view To obtain knowledge of the
strength Of the iron generally used FOR the construction Of
boilers pipes &C. In order to acquire satisfactory data
variety of plates manufactured from the best quality
of ron OF different localities, submitted to direct
experiment first, by tearing them asunder in the
direction of the fibre and second it, The in
conestablc strength per square inch in TONS was found
to be o. in the direction of the FIBRE and ~ 20 across
the fibre. From this it appears that there is differ
cnce In the strength of iron plates whether torn in the
direction of the fibre against ita uniformity of
strength probably arising from the superior in
which that article is manufactured. 1t has been
thought that the veted point IN such constructions
only strong but absolutely stronger thnn the plate
itself 1t ascertaned however that the strength of
iron plates, compared to their rveed joints not
only weakened to the extent of the quantity of metal
punched receive the rvets but in the following
ratios viz 1000 to 700 in the double riveted joint
and 900 to $50 in the singe-rivetcd joint The maxi
resistance of single veted plates does not exceed
27 900 pounds to the square inch and taking into
the crossing Of the joints and other circumstances
peculiar to sound construction "a 900 pounds has been
found to be the maximum strength of ryeed plates and
for boilers and similar construction.
Ia,proren,ets WearingAn invention has been brought
forward consisting of particular adaptation of machn-
the art OF weaving the object being to relieve the
yarn in the loom from unnecessary strain arising from the
action of weaving The strain to which the yarn is
cessary subjected according to the present ordinary
system of weaving by hand and power LOOMS arises chiefly
from three great sources viz from shedding, from
ton by the motion of the cloth bcam and from the
| action of the lathe in striking the shot home. In
Quoted according to the present system, the yarn
ssains the reaction of each of these actions in
| sion but in weaving by power the three actions
joined and fall on the yarn at the same time hence the
severity of the power loom in action compared with the
hand loom weaving by proposed system these
of strain quite removed viz that arising from
shedding and that from traction by the motion of the
cloth beam and thus the necessary strain to which Me
yarn is exposed in weaving by power is by this
system reduced to that only resulting from the required
traction Of the yarn to make good work the striking
home Of the shot, to less than third Of its original
amount. The power loom is thus by this in nd
vance OF what the hand loo by any which pres
system possesses accomplish The improvement
consists simply in making the yarn beam turn forward
by the action of machinery SO as to make the delivery
of the yarn meet the strain to which IL would otherwise
be exposed by the lateral detection of the yarn in shed
ding and to tighten the yarn again 1t may require
either by the residence of the yarn beam alone, con-
jointly by the forward motion of the cloth beam the
of the lathe is being given without the res
! ence of the yarn beam.
Standard Of Measures 1t is necessary in all countries
where is in any way encouraged that some
standard of and weight should be adopted In
this country and Britain the yard is the standard of
measure the length of which is determined by the vbra-
ton Of the seconds pendulum at London in a at
the level of the but the length of the pendulum
varies in different laudes the yard is little longer in
New York than London because of the pendulum in the
former place being about the onc-eghth an inch longer
than in the latter This yard is divided into thirtysix
inches, three feet The old method Of teaching the
Oh WIS very VAGUE aS ~ With
the statement that Three barleycos make one inch "
which, to say the best, remarkably uncertain meth
cd of fixing standard, barlcycorns very liable
| differ considerably in size.
The French, the other hand take quarter of the
earths circumference, and dividing that into ten mil
lion parts, take of tem which s equal to 39-37l
standard inches, and calling it metre form all their
weights and As the circumference of the earth
Is not likely to vary much with time temperature and
cannot meet with the accident which bec the standard
British yard which melted in the old Houses of
Parliament when they burned it is decidedly the
most accurate but long have given and
known standard, it does not much matter what it is
Destroying The Nerves Of Teeth 5 E2etriciyAn interest
ing paper this subject recently read before the Col
lege OF Dentists in London, by T. Harding, NJ d., in
which he described his in cauterzng the pulp of
decayed teeth by the of current of electricity He
employs for this purpose compound Since battery
posed of six pairs of zinc and platnized silver plates
cells excited by dilute sulphuric acid The conducting
wires which from the opposite end plates and form
the circuit terminate in tips OF fine platinum wire
formed into loop The sides of this loop are brought
parallel not touching but together, then in
troduced into the cavity of the tooth to be operated
upon handle is then touched which closes the cir
cult and the electric current flows along the wire raising
the platinum tips to white heat, which destroys
the pulp of the TOOTH The white light of the platinum
points inmines the cavity and allows the operator to
perceive what he is doing The operation is associated
with little pain and should precede the filing of decayed
teeth which cause pain from exposure Of the pulp This
process ordinary toothache and 1t may be
used with decided advantage in aost every of tooth
disease If carefully performed DR. Harding also stated
that 1t especially applicable 10 relieve neuralgia
the face dependent upon affected teeth This form of
teeth disease very prevalent in country and