The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1892-09-23
INSTRUMENTS FOR OBSERVATORY


1ne University Receives Appliances for
Recording tho Weather.
Frof. ) N. Tayloc announces the receipt OF
sessfai nne instruments for the observatory of
the university. These are q barometer OF the
United states signal service pattern, an anemo.
meter also United States pattern; q Green
standard rain gauge, . United etates signal
service wind vane, maximum and thermome.
Ter OF the latest pattern and . Draper thermo-
graph or STRENGTHENING thermometer.
Inc barometer has tho latest Improvements 30
arranged As to dispense with corrections for
capillary action or instrumental error. The
nrstof these errors 10 perceiysble to the ordi-
nary observer In the fact that the mercury inside
the glass looks rounding, like the point of .
confcai rifle bullet The tube Is 25-lO0.inch
bore and IL freed from air ana moisture by boil
ing the mercury in the tube. The barometer is
mounted on an upright mahogany board, to
which 1t 10 attached by . suspension peg or
piece by ring on the top Of the metal cylinder
In which the tube IL contained. On the bottom
the containing cylinder ends in the mercury
cistern aud this is held inside OF a collar at
Eached to the bottom Of the mahogany board.
FOR adjustment three screws reach through this
collar and bind on the outside of the contain
Ing eistern, thus permitting of very fine adjust
ment Behind both the mercury cistern aud
the column are white opal glass plates to reflect
light and aid in reading the instrument. A
vernier enables readings OF the instrument to DO
made to the l-1o0 part OF an inch.
Ihe thermometer or wind gauge IL a machine.
very simple in principle. 1t 10 simply two arms
joined together at right angles aud piyoted on
post around which it revolves freely. On the
end OF each arm are half spherical cups, facing
horizontally. The result of this 10 that one cup
is always turned with its hollow side to the
wind, whilst the cup on the opposing side pre-
ssnts Its rounding side or the least resistance to
the air. Set up in the air. therefore, it moves
with the very slightest breath. The arms are
connected with and actuate an upright bar,
which in turn moves the registering apparatus
for recording the speed of wind currents. The
registering apparatus 10 electric and IL 20
ranged that pencil, whose position up or down
10 determined by the speed of the wind, moves
across the face OF cylinder revolving by clock
work. On this cylinder 10 a sheet marked in
hours and days. each sheet representing week.
Thus when the sheet Is removed 1t contains an
exact diagram OF the speed OF the wind for
every hour OF the week.
The thermograrh, or self-registering Their
mometer, il the invention OF DR.. Daniel Draper.
The instruments looks little like IN ordinary
clock. The face carries with 1t paper desk
covered with concentric circles and radiating
lines. This face revolves, carrying the disk
with 1t. The concentric circles represent de-
gress. and the radiatng lines hours of the day.
The thermometer proper is fixed, ana in priu-
ciple IL the same ~ any other The falling and
rising of the mercury, however, is made to actu-
ate An arm in and out across the face of the
clock along the lines which mean degrees And
40 this arm carries pen on its end 1t makes its
mark, so to speak, on the proper degree indi-
eating the temperature The clock face IL con-
stantly moving, of course, and when IL il
started carries around the paper disk with It,
and the pen makes very irregular looking
mark across its facs, but one which accurately
fixes the temperature for any hour OF the week.
NJ 49, t. H.
and the clock face revolves Just once in that
period.