National Republican. (Washington City (D.C.)) 1872-1888, 1881-04-21
SCIENTIFIC TALK.
THE NaTloNAL AcADEMIcrANs.
Papers Read Before the Session Yesterday-Moun.
tain Observations-Soil and Diseases-Elec-
trio Light Photometry-Pedal De-
yelopment-Pendulum Work.
The National Academy of Sciences were

! The National Academy of Sciences were
in session all day yesterday. They met at eleven
| o'clock, and held secret session for the transac-
ton of business, the election of members, &c.
| After recess for lunch another session was held,
| beginning at two o'clock. There was quite large
attendance, the number of ladies being especially
noticeable. Many of them were young and charm
| ing which is conclusive evidence that science
does not wither all it charms or charm all it
withers. There were but few members of the
| academy present during the session, and so the
papers which were read did not give rise to very
much discussion. The venerable president of the
academy, William B. Rogers, of Boston, presided,
and announced the subjects of the papers
MOUNTAIN OBSERVATIONS.
| The first paper was entitled Mountain OBJ
servations," and was read by Professor Langly, of
the Allegheny Observatory. He said that they
had about arrived at point in solar science where
they were met with the difficulty of penetrating
the intervening medium which separates the OBJ
server from the object of his search. The char
acter of this medium affected all galvanometric OBJ
servations upon the heat of the atmosphere which
surrounds the sum- He had taken large number
of observations but the result affected by the
temperature at different times He thought that
the only remedy was to carry out Newton's idea
and take the observations from some very elevated
station, say ten thousand feet or at elevation of
| three, four, and ten thousand feet The planet
seemed to be surrounded by dusty streams. The
whole science Of solar physics depended upon the
character of the elevated station. At an elevated
station it will be possible to determine in two
three days what would otherwise require several
years. He spoke of experiments in pursuance of
this theory being conducted during the coming
year in connection with the Signal Service.
THE SOIL AND DISEASES.
The next paper, ON The Rates of Flow of Water
and the Capacity of Soil to Filter was read by
R. Pumpelly and was an interesting account of
the relation of geology to sanitary science. The
main portions of the paper have been published
by the National Board of Health. He said that
the great interest in sanitary science had lead to
a very thorough examination of the connection
between the lower forms of animal life and cpl
demic diseases. This form of life was bred in
the corrupt masses of cesspools vaults, and ceme
teries, and then communicated to the SOIL A Sc
ries of experiments had been carried on to ascer-
tain the capacity of different kinds of soil as
filters. 1t was ascertained that sand afforded
no protection against the transmission of disease.
In houses built on sandy soil, and even when
the cellar was above the ground level, there was
danger of contamination from foul places. The
experiments that had been made were illustrated
by charts showing the methods adopted to test the
ltering capacity of the different variety of soils.
Upon the conclusion of the reading of the paper a
the gas-ppes and the dissemination of the gaseous
products through the soil was considered an efec-
tive agent for destroying the germ of disease.
PROFESSOR LOOMS PAPER.
In the absence of Professor Elias Loomis, Pro-
fessor Able read his paper on the Reduction to
Sea- Level of Barometric Observations Made at
Elevated Stations" The object of the paper was
to show the cause for the deviations between the
observations at higher and lower stations from the
T g -, o11,o
in the defective assumption that the temperature
is the same at the top and bottom of the mountain.
The reduction of barometrc levels to the sea-level
depends largely upon local circumstances. At
Mount Washington the deficiency in Laplace's
formula is eighty-six per cent, even when the
temperature remains the same. Avery interest
ing paper was read on
ELECTRIC LIGHT PHoToMETRY"
by Professor George F. Barker of the University of
Pennsylvania. He said that there was a wide
difference in the methods employed in ascertain
ing the power of the electric light. The results
reached by the manufacture of the various
machines are discordant. In scientific papers the
maximum value is from 200 to 800 candles to
the horse power. The prospectus of the manu-
featuring companies gives from 1900 to 1000
candles to the horse-powe Everybody admits
that the minimum is too small and the
maximum too large. How to ascertain the proper
power is the question. The theoretical maximum
is $500 candles to the horse power This gives to
the machine an efficiency of 100 per cent. Such
result is impossible as there is a loss
quite equal to fifty per cent. The mean
value for 200 to 100 candles can be ac-
cepted as about right. In electric lights the
amount of light given out from all directions is
just the same. Hence the difficulty in getting the
power of the light The speaker suggested as a
remedy that the light be measured while the car
bons are revolving, which will give the mean of
the intensity of light in all directions. Professor
Barker also read paper on 1.-The Condenser
Method of Measuring High Tension Current"
PEDAL DEVELOPMENT.
The next paper was read by Professor E. D. Cope,
of Philadelphia, on THE Relations Between
Strains and Impacts and the Structure of the Feet
of Mammalia." The aim of the paper was to show
that the development of the number of the lower
limbs of animals was due to the ground upon
which they walked. The soft ground spreads out
the toes and leads to their separate development,
while hard ground develops the middle toe at the
expense of the Others. The same principle ap-
plies to the development of the bones in the lower
portion of the extremities. The paper was Illus
trated by drawings on the blackboard. The last
paper, on
THE PROGRESS OF PENDULUM WORK.
read by Professor C. S. Pierce of Boston. The
academy then adjourned until this morning, at
eleven o'clock, when business session will be |
held, and in the afternoon public session. when !
scientific papers will be read. Last evening the |
members of the academy attended a reception |
given by Admiral Rodgers, at his residence |
near the Naval Observatory.