50 
Hjælp af dette Apparat, som ved et Stykke Kautschukror 
var forbundet med et lidet Reservoir, bestemt til Optagøjjle 
af den ved mulig Opvarmning udskudte Del af Indholdet, 
bestemtes jm Ildvidelsescoefficienten af det anvendte Glas- 
rør med renset Kviksølv. som nogen Tid før Forsøgenes 
Udførelse under Udkogning paafyldtes Pyknometret. Med 
dette Apparat, som jeg vil betegne som Pyknometer No. 3. 
udførtes til den Ende følgende Veininger. 
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 pycnometer. 
With this apparatus, which I will designate ‘Pycnometer 
No. 3/ were performed the following determinations of 
weight: — 
Pyknometer mod Indhold. 
Vægt 
Gr. 
I Luft 
af 
sp. Vregt. 
Pycnometer with Contend. 
Weight 
in 
Grammes. 
In Air 
with a Sp. 
Gr. of 
30. 
Pykn. No. 3 tomt 
10.8654 
0.0012 14 
30- 
PyCn. No. 3 empty .... 
10.8654 
0.0012 14 
3 !• 
- 3 » 
10.8653 
0.0012 14 
3 1 - 
— - 3 » • • • • 
10.8653 
0.0012 14 
32. 
- 3 med Kviksolv 
af o° 
I95'9265 
0.0012 1 5 
32. 
— - 3 with mercury 
of o° 
495-9265 
0.0012 15 
33- 
3 n n 
» 0 
I95-9265 
0.0012 15 
33- 
— - 3 » 
» 0 
I95-9265 
0.0012 15 
34- 
- 3 v » 
„ 20 
I95-3588 
0.001205 
34- 
— - 3 » 
,, 20 
I95-3588 
0.001205 
35- 
3 11 55 
,, 20 
195-3592- 
0.001205 
.35- 
— - 3 >• n 
20 
195-3592 
0.001205 
36. 
3 55 55 
» r 5 
195-4993- 
0.001205 
.36. 
- 3 » » 
11 15 
195-4993 
0.001205 
37- 
3 » n 
» 0 
195.9276 
0.001205 
37- 
- 3 r ' ■ « 
» 0 
195.9276 
0. 001 205 
38. 
- 3 tomt 
10.8650 
0.001203 
38. 
— - 3 .empty 
10.8650 
0.001203 
39- 
- 3 med rent V and af 4 0 
24.4621 
0.001202 
39- 
— - 3 with pure water 
51 -4° 
24.462 1 
0.001202 
40. 
3 » n • n 
» 4 
t 24.4634 
0 
O' 
0 
q 
6 
40. 
3 r 51 51 
55 4 
24.4634 
0.00 1 190 
Alle disse Veininger. ere 
udforte 
efter Substitutions- 
These weight-determinations 
were 
all performed ac- 
methoden ved Afiæsning af Svingninger paa en Vregt, 
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 finere Veininger, som jeg har foretaget i Anled- 
ning af disse Arbeider, benyttedes en Platina lodsats fra 
Deleuil i Paris, hvis Correctioner jeg i Forveien havde be- 
stemt ved flere 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 Veiuingerne iagttoges altid Temperatur og Ba- 
rometerstaud af Luften i Veieværelset, hvorimod dens Fug- 
tighedsgrad i Mangel af Observation passende ansattes, en 
Mangel, der ikke har nogen mærkbar Indflydelse paa For- 
søgenes Paalidelighed, da selv en saa grov Feil i Ansæt- 
telsen af Luftens relative Fugtighed som 25 °/ 0 under de 
her omhandlede Forhold kuii virker paa det endelige Resultat 
med en liden Feil i 6te Decimal. Efter disse Data er Luf- 
tens specifiske Va*gt under Veiuingerne paa vanlig :Maade 
beregnet og ppført i Tabellen. Pyknometret blev for Jiver 
særskilt opført Veining indstillct paany for Temperaturen 
. 0° i finstødt Is og forøvrigt i Våndbad. hvis Temperatur 
under stadig Omrøring holdtes constant, ligesom det mindst 
en Gang for hver anden Veining tømtes og fyldtés igjen 
med det Søvand, hvis Volum skulde bestemmes. Ingen 
Indstilling toges for god, med mindre det lykkedes i mindst 
lo Minutter at holde Temperaturen såa constant, at Ther- 
mometret ingensindé viste Variationer af O/ l eller derover. 
Til Brug ved Aflæsniug af Vandbadets Temperatur tjente 
cording to the substitution method, by reading the oscilla- 
tions of a balance, the sensibility of which, when not' 
loaded, amounted to \A mar for every division of the scale, 
diminishing, on being loaded with successive weights, at a 
comparatively uniform rate down to 1.9 m * r , when loaded 
with 200^ r . For 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 start- 
ing on the Expedition computed from a series of closely 
agreeing determinations of weight performed with an ex- 
cellent balance (made by P. Bunge), its sensibility when 
loaded to the extent here specified being nearly 0.14 w s' r . 
When performing the weight-determinations, the tempera- 
ture and the atmospheric pressure in the room were al- 
ways 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 in- 
fluence, on the trustworthiness of the experiments, seeing 
that an error ol 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 
ol the air during the process of weighing was computed 
in the usual manner, and entered in the Table. For each 
successive determination, the pycnometer was plaeed in 
finely crushed ice, to give it the temperature of 0°, and 
lor every other required, in a water-bath, which by constant 
stirring was kept at an equable temperature ; it was emptied. 
