The Hawaiian gazette., 1878-08-14
Scientific Wondcrs.
PROFESSOR EDIsoNs LATEST DIscovERIEs-THE
TAsMETER, the ELECTRIC GOVERNOR, AND
THE MEGRAPHoNE.

just completed 1t is to be used in the scientific |
experiments to be made by astronomers from |
all parts OF the world at Denver, Colorado, next |
month during the total eclipse of the sun, visi- |
bic at that place. Professor Edison starts for |
that State on the 9Th of July, accompanied by |
Professors Draper, Parker and other scientists |
from this section of the country. The results |
thus far obtained FROM the tasneter have been
almost Incredible. Used in connection with the !
gavanometer OF Sir William Thompson, it has
been found to record the pressure of one FIVE
hundredth thousandth part OF an inch.
Hitherto the most delicate instrument known
to science for determining the heat in the differ
ent parts of the solar spectrum has been the
tbermopiIe. The great Improvement OF the tasi
meter over the tnermopile is Illustrated in q
simple manner by Professor Edison. A few
inches from the former be placed u hot iron. 1t
DETECTED the needle of an ordinary galvanom-
eter one degree; then be held his little finger
four inches from the tasimeter with the same
galvauometer, and it swung the needle around
six degrees. In explaining the workings OF his
new invention to u Herald reporter, in his la
boratory ut Menlo Park. the inventor made
number of curious experiments. " See herep
said he, taking up thin strip of vucanized
rubber, and placing it between two small upright
iron posts III his tasiineter, "this highly sensitive
to heat-a little causes it to expand. At this
end place my carbon l found out that silk
coated with conducting lamp black, pressed in
the form OF button. was wonderfully sensitive
to the passage Of the electric current. Put upon
it the pressure of one-half millionth of au inch,
and it will allow the passage of a current strong
enough TO defect Sir William Thomps0n's gal
vanometer one degree. OF course greater press
ure defects the needle more" Professor Edison
then took an ordinary galvanometer and put it
in al trio will hall
his hand four inches away from the vulcauite
strip. INSTANTLY the needle of the galvanometer
moved FIVE degrees Next he lighted gas jet
five feet away and the needle moved four degrees.
Then he held match distance of six inches.
and the heat Indicated eleven degrees IN the gall
vanometer. Breathing slightly on the galvanom-
eter expanded it sufficiently to mark thirty de-
grees. These results the Professor produced
without the improved gavanometer, which, he
explained, was infinitely more sensitive.
Professor Edison next introduced between the
posts slip of gelatine, in order to measure mos-
ture Moistening slip of paper slightly with
his tongue he held it three inches away. The
DETECTION eight degrees. A breath on the
gelatine moved the pointer thirty. five degrees. A
drop OF water on the end of his fnger, held FIVE
inches away indicated q moisture OF eleven
degrees.
The professor next explained the method pro-
| posed to be adopted IN the astronomical expert
ments to be made with his taslmeter. Instead
of vnlcanzed rubber, platina will be used. the
latter having been found to gam and lose heat
much more readily than the former The Tasi.
meter, unlike the one experimental on as above.
is to be smaller and of different material, brass
being used throughout 1t will be incosed in
receptacle of tin. which in turn is placed in
second receptacle Of the same metal. Between
the two will be kept boiling water for the pur-
| pose OF preserving eyenness Of temperature. as
boiling water attalDs no higher temperature than
III Fahrenheit. The spectroscope will then be
made to concentrate the heat into small open
ing IN the tasimeter, where, falling the plati-
na it will cause expansion and corresponding
pressure of the small carbon button allowing the
passage of the electric current 10 degree CON-
mensurate with the pressure. Attached to and
forming part of the tasimeter is an appliance for
measuring the degree of expansion or contraction
OF different metals under similar temperatures.
Professor Edison found the heat of his hand ex-
banded the platina one 6ve-thousandth part of an
inch.
The great inventor has already taken steps to
use his new discovery for the protection of ves
sells at sea. He stated to the writer his method
as follows: " arrange the carbon button as
mighty sensitive barometer, and, lncosing it in
case, connect it with the keel OF ship. | then
run wire to the captains room into an ordinu-
ry galvanometer. Any change of temperature,
as you see, is at once indicated. Goodness of the
water will contract and warmth expand and the
corresponding reflections be placed at once be-
fore the eye OF the captain. The approach of an
iceberg will, therefore, be known long before
there is danger of collision. IL may also be nsed
to indicate any abnormal heat in any part of the
ships hold thus giving timely notice of the
breaking out Of fire."
In experimenting on his tasmeter Prof. Edison
made highly valuable discovery in telegraphy.
Ever since the first line was successfully worked
by Prof. Morse the great and apparently insur-
mountable obstacle to constant and unnterrupt-
ed communication was the effect produced on
the electric current by changes in the atmos-
phere. Rain always made the lines work with
difficulty, and frequently 10 heavy storms The
escape Of the subtle fluid into the moist air
made the wires practically useless.
The Professors discovery is what he calls an
" electric governor" acting on the telegraph
line as a steam governor does on an engine. 1t
obviates the necessity of" adjusting the mag
net armature along the line. One placed in
the circuit regulates the entire line, preserving
an eVenness of current throughout. The loss
of 90 per cent OF battery power is felt no more
than corresponding gain. Dimlnution in the
strength of the battery from any cause, atmos-
pheric or otherwise, is prevented by the "igov-
ernor from having any perceptibe effect on
the instrument or any part Of the line The
Professor desired it to be understood that the
discovery was based on o suggestion by prac-
tical telegrapher.
Professor Edison has also found by his ex-
periments with the tasimeter that il will weigh
in6nilisimal articles as well as their moisture.
For instance, he took fibre of paper, and by
placing 1t in his new apparatus found it 10 be
quite heavy. Then he experimental on gnat,
connecting the instrument at the same time with
his most sensitive telephone. The result was
the DETECTION of the galvanometer to indicate
the weight of the dimnutIve insect, while the
telephone echoed the sound made by the insects
feet on the disk.
By arranging il with an anamoter arm and cup
and causing the lever to press on the tasmeter
it recorded the pressure Of faint gust OF wind.
Notwithstanding the heavy drains on his H.
tellect by the numerous wonders 10 process of
construction 10 his laboratory. the Professor con-
tinues daily at work perfectIng his megaphone.
DE placed the field megaphone 10 front Of his
laboratory. and gave the rubber tubes to The
writer so that be might personally test its strange
power. Then be hurried across lots nearly q
mile. and standing on the brow OF bill whis-
pered, DO you hear this p The words came
distinctly notwithstanding quite breeze was
blowing at the time. When he spoke in his