New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1899-01-08

NOVELTY IN ANERoID BAROMETERS- AN
OLD DIFFICULTY HAS BEEN oBvIATED.
Although the aneroid barometer is much
barometer, and is therefore much more con-
venently handled by the mountain climber, 1t
has serious disadvantage in the measure
ment of attitudes If mercuriaI instrument
is accurate at the outset the only corrections
which 1t is necessary to make in its readings
are based on temperature. And tables are
available that enable to make these
corrections without difficulty. The mountain
climber needs merely to make careful readings
and records and all the rest is easy.
But IL was discovered several years ago that
anerod barometer not only drops promptly
with a diminution OF atmospheric pressure, as
upon a mountain side but will continue to fali
slightly for considerable time thereafter. IL
the instrument remains at the same level For
instance, II the two types Of barometer were
put into an alrpump and the pressure promptly
reduced to fourteen inches 0he pressure that
would correspond to altitude OF about 2O,t'o
feet), the mercurial instrument would give the
proper reading Immediately. and remain IN
changed until the pressure was altered lne
aneroid would also give correct indications IN
starty, but IL ii stayed under the receiver OK
the airpump for week ii should continue dur
ing all that time to fall a little more
Now, in climbing a given peak, say in the
Andes, an explorer would not at once attain the
summit but would be compelled to struggle
on through period Of several hours, perhaps
two or three days. The popularity OF aneroids
just referred to would begin to manifest itself
as soon as ne reached a level only few thou
sand feet above his starting point, and would
continue to operate during the remainder OK
his ascent The readings Of the instrument,
when he completed his tosome journey, would
therefore be misleading And 1t would be a
difficult matter to apply suitable correction
to the figures.
An improvement In anerod barometers de-
signed 10 obvate the trouble in question is at
tracing attention just now among scientific
people Colonel Fl Watkn Chief Inspector OK
the Position Finding Department OF the British
ARMY. proposed modification of the apparatus
that should enable the user OF the barometer 10
throw il in and out OF gear When ii was de-
sirable to make reading, the indicating part
Of the instrument would be momentarily con-
nected with the rest. and an observation would
be made And then as possible, the
two parts Of the mechanism would be discon-
nected and the atmospheric pressure whether
upon it. Prolonged exposure to which alone
was due the fault referred to, would thus be
avoided
Edward Whymper the famous mountain
climber was persuaded to test one OF Colonel
Watkins new aneroids In the Alps last autumn.
He now contributes to THE London Times
letter announcing the result Before going to
Switzerland though Mr.. Whymper had the
barometer kept under the receiver or an ar
pump at pressure OF only seventeen inches
uhe normal sea-level pressure is thirty inches,
il viii be remembered) All that time, Of course,
the barometer was out of gear. But as soon as
ne threw; IL in ne found that 1t had not fallen
any during the test
The experiments in the Alps were made by VS.
Ting places whose exact height above sea
level was known, having been previously de-
termined by Governmental surveys Mr..
Uhvmner went from one mountain 10 another,
with occasional descents into valleys He at
,ained heights of over 10000 feet, and wound
No al Geneva only 1227 feet above the sea
level During a period OF forty days he noteo
a total drop Of u inch. This amount is much
less than would have been experienced with the
old STYLE Of anerod under the same circum-
stances ard is equivalent to an error or nun
dred feet less
NJ Whvmper IS satisfied that with better
,oanapement the drop could have been lesseneo'
He mentions several instances in which no laii
since the last observation was discerhiot no
has confidence that in the right hahds great
things can be accomplished with the new instru-
ment