Fort Worth gazette. [volume] (Fort Worth, Tex.) 1891-1898, 1891-06-28
POPULAR SCIENCE.
AN INSECT THAT ACTUALLY
BORES METALS.
Removing Tannin From Tea-Important
Experiments With Steel wire-A
New Flying Machine.

Much interest is being reused in Germany
over the discovery of an insect that ac'
tually bores through metal pipes. For 4
considerable length of time very mysterious
leaks have been found in lead pipes
and in a few copper pipes. The
openings looked like holes through which a
nail had been driven. At last, according
to Gesundheit's ingenieuter, the author OF
the trouble has been found. An insect of
the wasp character was found boring the
was Of a rounded form. about one-quarter
of an inch long by one-eighth inch wide,
and the penetration was through the entire
thickness of the metal. Though of rare oc-
currence, well authenticated instances OF
similar injuries by insects are on record.
~
The ordinary Chinese tea is always rich
in tannin. Mr.. H. Grimshaw says this
tannin is readily absorbed by suitable ami
NAL, substances, such as horn shavings,
dried albumen, add clippings, and the like.
1t is preferable to hide the material to the
tea in the dry condition before the infusion
is made But it may also be added to the
infusion, or the infusion may be passed or
filtered through layer of the substance3
The quantity of animal substance to bs
added to the Misunderstanding material
must be determined by the amount of tan
min contained in it. In the case of tea the
proportion may vary from one to two parts
of animal substance to ten parts of tea.
This discovery is looked upon as of imports
ance, owing to the fact that tannin in tea
renders the tea unwholesome for 56me
persons. -.
In the current number of the Philosopif-
cal Journal Mr.. F. ]. Smith gives an aca
count of some new methods of investigat-
ing the points of recalescence in steel and
iron. The object of the experiments was
to discover the time connection which ex-
lists between the change of form and the
change of tempe nature. Several methods of
experimentation were tried. and the follow
ing was the one finally adopted: The upper
vertically; the lower end was attached to a
long light lever of aluminium, so arranged
that small change of length of the wire
caused large movement of the end of the
lever, which traced line on the smoked
surface of paper rotating on an ordinary
physiological chronograph cylinder. A
platinum platino-rhodium thermo-couple,
twisted around the wire where it was
heated, was in circuit with q Deprez-
D'Arsonval galvanometer. BY means of
this combination the temperatures at which
the changes of length of the wire took place
were read. The movements of the beam of
light reflected from the galvanometer were
recorded on = moving Photographic film.
The outcome of the experiments was that
the changes of form of the metal under ex-
animation took place at the times of change
of temperature, so that curve so traced
on the smoked paper can be used as an in
dex of the changes of form and the changes
of temperature. -.
Thinking it probable that these changes
might be accompanied by some sounds at
the critical points, the following apparatus
vas constructed: A mica disk was fitted
into circular recess turned out of piece
of wood. The steel wire under examine
ton was attached at one end to the center
Of the disk, at the other to vertical post
The front of the recess into which the mica
disk was fitted was furnished with two
sounding tubes. On heating the wire a
certain temperature was reached at which a
sharp cracking sound was heard. AS the
temperature was increased this ceased !;
then, on removing the flame, at the same
temperature at which the first sound was
heard. a second similar sound occurred
This took place at the point of recalescence.
As the wire cooled this ceased, and then,
when temperature of 400 degrees C. was
reached, very sharp sound was emitted.
This third sound appears to take place at
the second critical point observed by NJ.
Osborn. The wire used in these expert
ments was steel pianoforte wire, annealed
and Strengthened. The last experiment
was also arranged so that the steel wire
when heated should be in strong magnetic
field Repeated trials showed that the
sounds produced were in no way altered
by the fact of the wire being in the magnetic
field. -.
A new flying machine is now before the
public, according to the Scientific Ameri-
can. It is the invention of Mr.. II. Maxim,
and works on the principle Of kite. The
experimental device consists of thin sheet
or Kite four feet wide and thirteen feet
long, which is propelled by screw capable
Of 200 rsvolutions per minute. According