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50
Hjælp af dette Apparat, som ved et Stykke Kautschukrør
var forbundet med et lidet Reservoir, bestemt til Optagelse
af den ved mulig Opvarmning udskudte Del af Indholdet,
bestemtes nu Udvidelsescoefficienten af det anvendte
Glasrør med renset Kviksølv, som nogen Tid før Forsøgenes
Udførelse under Udkogning paafyldtes Pyknometret. Med
dette Apparat, som jeg vil betegne som Pyknometer No. 3,
udfortes til den Ende følgende Veininger.
Pyknometer mett Indhold. Vægt Gr. I Luft af sp. Vægt.
3°- Pykn. No. 3 torat....... 10.8654 0.0012 14
3>- — . - 3 10.8653 0.001214
32- — - 3 med Kviksolv af o° 195-9265 0.0012 15
33- — - 3 il .1 il 0 195-9265 0.001215
34- — - 3 il il il 20 ■95-3588 0.001205
35- — - 3 il 11 il 20 195-3592 0.001205
36- — - 3 il il il 15 195-4993 0.001205
37- — - 3 il il 11 0 195-9276 0.001205
38- — - 3 torat....... 10.8650 0.001203
39- — - 3 med rent Vand af 4° 24.462 r 0.001202
40. — - 3 •i il 11 il 4 24-4634 0.0011 go
Alle disse Veininger ere udførte efter
Substitutionsmetoden ved Aflæsning af Svingninger paa en Vægt,
hvis Følsomhed uden Belastning beløb sig til 1.4 Mgr. pr.
Delstreg og for stigende Belastning temmelig jevnt aftog
indtil 1.9 Mgr. ved 200 Gr. Belastning. Til disse saavel
som alle linere Veininger, som jeg har foretaget i
Anledning af disse Arbeider, benyttedes en Platinalodsats fra
Deleuil i Paris, hvis Correctioner jeg i Forveien havde
bestemt ved tiere vel overensstemmende Veininger paa en af
P. Bunge forarbeidet fortrinlig Vægt, hvis Følsomhed for
de her omhandlede Belastninger beløb sig til omkring 0.14
Mgr. Ved Veiningerae iagttoges altid Temperatur og
Barometerstand af Luften i Veieværelset, hvorimod dens
Fugtighedsgrad i Mangel af Observation passende ansattes, en
Mangel, der ikke har .nogen mærkbar Indflydelse paa
Forsøgenes Paalidelighed, da selv en saa grov Feil i
Ansættelsen af Luftens relative Fugtighed som 25 °/0 under de
her omhandlede Forhold kun virker paa det endelige Resultat
med en liden Feil i 6te Decimal. Efter disse Data er
Luftens specifiske Vægt under Veiningerne paa vanlig Maade
beregnet og opført i Tabellen. Pyknometret blev for hver
særskilt opført Veining indstillet paany for Temperaturen
0° i finstødt Is og forøvrigt i Vandbad, hvis Temperatur
Under stadig Omrøring holdtes constant, ligesom det mindst
en Gang for hver anden Veining tømtes og fyldtes igjen
meel det Søvand, hvis Volum skulde bestemmes. Ingen
Indstilling toges for god. med mindre det lykkedes i mindst
15 Minutter at holde Temperaturen saa constant, at
Thermometret ingensinde viste VariationoT af 0.°1 eller derover.
Til Brug ved Aflæsning af Vandbadets Temperatur tjente
absolutely unavoidable. With this apparatus, which was
connected by a caoutschouc tube with a small receiver for
collecting any portion of the contents that, in the event of
the instrument becoming warmer might possibly be expelled,
the coefficient of expansion of the glass tube was now
determined by means of purified mercury, which, shortly
before the commencement of the experiment, had, when
boiling out the air, been introduced into the pyenometer.
JkVith this apparatus, which I will designate ’Pyenometer
No. 3,’ were performed the following determinations of
weight: —
Pyenometer with Contents. Weight in Grammes. In Air with a .Sp. Gr. ol’
3°- Pyen. No. 3 empty .... 10.8654 0.0012 14
3i- — "3 10.8653 0.0012 14
32- 3 with mercury of o° I95-9265 0.001215
33- — - 3 n 0 I95.9265 O.OOI 2 15
34- — - 3 I! 20 195-3588 0.001205
35- "3 11 20 195-3592 0.001205
36. - 3 >1 15 195-4993 0.001205
37- - 3 i- li 11 0 195-9276 0.001205
’l 38. 3 empty..... 10.8650 0.00x203
39- " ■ 3 with pure water li 4° 24.4621 O.OOI 202
40. - 3 ,1 ■i 4 24-4634 O.OOI 190
These weight-determinations were all performed
according to the substitution method, by reading the
oscillations of a balance, the sensibility of which, when not
•loaded, amounted to 1 Am,jr for every .division of the scale,
diminishing, on being loaded with successive weights, at a
comparatively uniform rate down to 1.9 ""■’r, when loaded
with 200For the above-mentioned as for all accurate
weight-determinations involved in these labours, I made
use of a set of platina weights procured from Deleuil in
Paris, the corrections of which I had previous to
starting on the Expedition computed from a series of closely
agreeing determinations of weight performed with an
excellent balance (made by P. Bunge), its sensibility when
loaded to the extent here specified being nearly 0.14m?r.
When performing the weight-determinations, the
temperature and the atmospheric pressure in the room were
always observed, but the relative humidity not having been
found by observation had to be roughly estimated, a source
of inaccuracy which however can exert no appreciable
influence on the trustworthiness of the experiments, seeing
that an error of even 25 per cent in the computation
of the relative humidity of the atmosphere would affect
the final result only by occasioning a very small error in
the 6th decimal. From these data, the specific gravity
of the air during the process of weighing was computed
in the usual manner, and entered in the Table. For each
successive determination, the pyenometer was placed in
finely crushed ice, to give it the temperature of 0°, and
for every other required, in a water-bath, which by constant
stirring was kept at an equable temperature; it was emptied,
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