National Republican. (Washington City (D.C.)) 1872-1888, 1880-09-01
AMERICAN SCIENTISTS.
Interesting and Valuable Papers Read
and Discussed,
Washington represented by Professors
Riley and Elliott.

Tho Cotton worm-EIeot Lighting.
BosToN Aug. 3i.--The American associa-
tion met again In general session this morn
Ing for the transaction Of general business
The first business was the election of officers
for the meeting Of 1881, and the following were
chosen: President, Professor G. J. Brush of
New Haven; secretary, Professor @. " Riley
Of Washington; treasurer, Professor W. s.
Vaux of Philadelphia; president of section
A, Professor A. Mayer of Hoboken N. j.; Sec
retary, Professor John Trowbridgo Of Cam.
bridge; Secretary OF section B, Professor Will
lam Saunders Of Canada; auditory committee,
Professor Henry Whoalland of Salem and Pro.
fcssor Thomas Meehan Of Philadelphia.
A resolution providing for social reunion
Of several sections on the second evening Of
future meetings was adopted, and also one rec.
oghising the services OF the late General
Meyer, of the signal service. Another resolu.
tion was adopted providing for the appoint
mcnt Of q comm ittoo 10 select q series Of stars,
Stellar magnitude, for standards to bo reported
at the next meeting.
The following message was cabled this
morning to France:
"Wheroas to-day August 81, Is The ninety
hhh birthday Of M. De Chevreu the senior
member Of the French academy, therefore
Resolved, That tho American Association for
the Advancement of Science, now in session
III Boston, send their hearty congratulations
with the hope that his life and labors may be
prolonged, ut least, to full century,"
In tho department of physics papers were
read as follows Upon the Use of Mercurial
Thermometers at High Temperatures" by
Professor Silas w. Holman; "On tho Move
ments Of Physical Constants" by Professor
Alfred NJ, Mayer, and remarks were made on
Mr.. @. s. Piercos paper "On Ghosts In Ruthor.
fords Gratings." In the chemical section Pro-
fcssor A. A. Brcneman Of Cornell exhibited
the results of experiments to obtain new col.
ors for common gray stone ware now decor
ated only IN blue Tho samples exhibited
showed that the range of colors which can be
obtained for ware Is very great vase was
shown upon which vine In green was painted
upon the ordinary gray body Of stone ware.
This cheap ware may in this way be made the
basis Of a new process of underglaze decora.
tion, in which the entire piecc-color, glaze
and body-is completed at a single burning.
The theory OF the new process rests upon tho
thickness aud comparative impresslbility Of
the glaze.
PROFESSOR RILEY ON THE coTToN.woRM.
Professor Riley of Washington read an
interesting paper on recent practical re.
suits of the cotton-worm inquiry by the
United States chronological commission
he stated the cotton-worm of tho south
is small looping caterpillar tho young
or larva of u moth known to science ms
netia mgillacca. While there nre many other
insects hjuriously affecting the cotton.pant
this is the worst Of all, and careful statistics
show that the people of the south have suffered
an annual loss since tho war of about SIS 0O0,- |
COO from its ravagos. Up TO the year 1872
the planter was at the mercy of this insect as |
no attempt had beel made to do anything
more than to kill few Of the parent moths |
nN NtFan n
and poisoned sweets. Unfortunately this |
was always done either in summer |
when the worms were abundant, or in |
autumn, when the moths swarmed. Tho |
results were unsatisfactory--f because of |
difficulty in getting the cooperation of all |
persons IN given neighbOrh0od; second, be-
cause most OF the moths that swarm in the |
fall of the year are destined to perish Tho
season when moths can bo most advantage.
ously caught aud Killed Is the early spring,
for, though only few may then he captured,
every one destroyed at that season helps
greatly TO prevent subsequent iUjury. Since
1872, when he first suggested tho use of paris
green, or more practically 1873, this mineral
has been used with great success aud satisac.
tiOn to destroy the worm. LAST year the com.
mission introduced as q substitute u refuse
material obtained in the manufacture of ami
line colors, and IL has given such satisfaction
that the demand cannot be supplied 1t costs
tects pound for pound twice as large
mn arcn. with it planters HAY protect their
fields at a nominal first cost OF five cents per
acre. All these substances are posons, and
have 10 be used with tho greatest care. In
other Investigations aud experiments he had
discovered that pyrethrum roseum, the powder
OF which he found year ago, wRs wonderfully
effective in destroying the worm. The only
question WAS to reduce Its cost, as IL Is II
European plant and has only begun to be cul-
tvnttd In California. II can now be produced
Tor hlty cents pound aud experiments this
year show that it may be not ouly used rs
an alcoholic extract diluted with water, but
by the powder simply being mixed In water II
pound ol this powder ia forty gallons of water
Will 60 as far as pound of paris green.
1t is perfectly harmless to man and
other animals, but it is certain death to
the worm, Tho methods Of applying
these substances have been to apply them
eithor wet or dry-thrown either in powder
or IN spray upon the plants from above.
Professor Riley instanced various improve.
ments designed TO ecOuomlzo material in
spraying the leufaud expressed his convictions
that before The end OF tho season no would be
able by improved appliances TO cover three
acres with tho same material that Is now
used for single acre, thus still further reduc-
lug tho cost Not only this, but he would be
t1c to throw the poison from below upward
Oh tho under side OF tho leaf, so that il would
uunelc uHu not w Wbsueu OH Dy rams aud 50
that il would Kill not only the worm but the
parent moth rs she sucks at the nectar thus
poisoned
ELECTRIC LIGHTING,
Mr.. H. b. Elliott OF Washington read paper
Oh electric lighting as applied to large areas.
lie instituted comparison between the relil-
tive cost Of the lighting of large areas by
illuminating gas aud by electric processes,
deciding IN favor of tho latter He thcn :
compared the relative efficiency Of several
processes Of electric lighting, showing the I
greater economy of the process known US that
OF tho electric arc" over the "incaudescent," |
so called, and over the combination of the two c
known as the ''caudles" Of JaJlochkoa and of (
Wilde, the! electric are" process being in tho /
lighting of large areas by fur the most econom. |
ical, aud its success for this purpose is now /
beyond question. I
The electric arc and the incaudescent pro.
CCsses however, are not TO be considered in
the light Of rivals, the former being specially
adapted to the lighting Of large areas, while
the latter 50 far as successful, is designed for
small spaces, as for domestic and like pur. I
poses He then treated the relative economy S
Of large and small electric lights, showing that /
the economy Of largo electric lights greatly
lrauscends that Of small ones. He dis. {
sussed the mutual action Of electric currents, /
\ knowledge of the law Of which lies at thu l.
- a. a o