14 



Da jeg Vaaren 1877 blev opfordret til at overtage 

 disse Arbeider, var der kun givet mig faa Dages Varsel, 

 saaat jeg havde de største Vanskeligheder med at faa ud- 

 ført selv de aller nødtørftigste Forberedelser, og naar det 

 alligevel rykkedes at faa Alt tilfredsstillende ordnet for 

 Afreisen, da skyldes dette udelukkende den Beredvilligbed. 

 hvormed Hr. Professor Waage bistod mig blandt Andet og- 

 saa med Indredningen af det chemiske Laboratorium ombord. 



Det paa Expeditionens forste Togt i 1876 fremher- 

 skende ualmindeligt stormfulde Veir gjorde det i hoi Grad 

 vanskeligt ja næsten ugjorligt at udfore de chemiske Obser- 

 vationer ombord, og det Udbytte. som af Svendsen hjembragtes 

 fra første Togt. indskrænkede sig derfor i denne Branche til 

 17 Luftprover. hvoraf desuden 3 ved Uheld senere gik tabt. 

 Det rolige Veir. som de to sidste Aar begunstigede Expe- 

 ditionens Arbeider, tillod mig derimod paa de Togter, hvor- 

 med der var givet mig Anledning til at medfølge, at ind- 

 smelte"et større Antal, idet der for disse Aars Vedkom- 

 mende erholdtes 80 Luftbestemmelser af de hjembragte 

 Luftprover. hvoraf 9 vare indsmeltede af Hr. Schmelck. 

 Naar Udbyttet ikke er ble vet større, da har dette sin Grund 

 i. at talrige Observationer gik tabt uogle faa ved Uheld 

 muler Analysen men de fleste ved Iheld under Indsmelt- 

 ningen. Saaledes var der til Brug paa sidste Togt fra 

 Kiichler & Sohne i Umenau sendt mig nogle Luftopsam- 

 lingsror. hvoraf over 75 °/ tiltrods for den omhyggeligste 

 Behandling sprang enten under [ndsmeltningen eller efter 

 samme. Luftprøverne ere alle analyserede ved det afFranck- 

 l.i tid ogWard 1 angivne Gasanalyseapparat, saaledes at Kul- 

 syren er fjernet med Kalilud og Surstoffet bestemt ved 

 Eorbrænding med Vandstof. De 14 førstnævnte Prøver 

 ere analyserede af Hr. Svendsen de øvrige 80 af Forfat- 

 teren. De erholdte Resultater tindes sammenstillede i 

 Tabel I. hvortil kan bemærkes følgende: De i Tabellen 

 opførte Temperaturangivelser ere mig meddelte af Pro- 

 fessor Mohn. Ved Angivelse af de Dybder, hvorfra Vand- 

 prøverne ere hentede, er ikke tåget Hensyn til. at Vand- 

 henteren forst lukker sig efter circa 7 Favnes Indhivning. 

 Ved de med * betegnede 10 Nummere var der i de til 

 Luftprøvernes < >pbevarelse benyttede Glasrør surna Feil. 

 uden at jeg dog har fundet mig foranlediget til at tillægge 

 disse mindre Vægt end de ( fvrige, da. man vel ikke kan 

 tanke sig Muligheden af en Lækage, uden at den. naar 

 Glasrørene i tiere Maaneder opbevaredes under en Tryk- 

 differents mellem det ydre og indre Gastryk a f circa 300 

 til 400""". maatte have øvet en mærkbar Virkning paa den 

 indesluttede Lufts Sammensætning. Jeg kan saa meget 

 trostigere tåge dem med i Beregningerne. hvor det gjælder 

 at opstille de almindelige Slutninger, som de ikke i syn- 

 derlig Grad ville bidrage til at forrykke. Udseendet af de 

 endelige Resultater. Alle Gasvolumina tindes i Tabellen 

 udtrykte i CC. perLitre udkogl Søvand reducerel til 0" og 

 760""" Barometerstand. 



Chem. Ser. Journ, 22- 



1869. 



When. in the spring of 1877. I was requested to 

 undertake these labours, I had but a few days' notice. and 

 experienced. therefore. very great difficulty in making 

 even the most necessary preparations ; nor would it indeed 

 have been possible to get everything satisfactorily awanged 

 in so short a time but for the readiness with which Pro- 

 fessor Waage' came forward to assist me; for instance. in 

 fitting up the chemical laboratory on board. 



The exceptionally heavy weather on the tirst cruise 

 in 1876. rendered it in the highest degree difticult. nav 

 well nigh impracticable, to perform the necessary experi- 

 ments on board ; and hence the chemical work done by Svend- 

 sen on the tirst voyage was. with regard to gas-determina- 

 tions, contined to collecting 17 samples of air, 3 of which 

 however were suhsequently lost. On the two last cruises of 

 the Expedition the weather proved mucli more favourable, 

 and I succeeded in obtaining a larger number of samples 

 (9 of them collected by Mr. Schmelck). with which. when 

 brought home. 80 air-determinations were performed. A more 

 satisfactory result would. however. have beeu obtained but 

 for the loss of numerous samples, some few from accident 

 when analysing the gass, but the great majority by reason 

 of the difficulty experienced in sealing. Thus, for instance. 

 on the last voyage 75 per cent of the glass tubes for 

 collecting air. procured from Kiichler et Sohne in Ume- 

 nau, notwithstanding the greatest care cracked either 

 during the sealing-process or after its completion. The 

 samples of air were all of them analysed in the apparatus 

 described by Franckland and Ward, 1 the carbonic acid 

 having been absorhed in a lye of potash and the oxygen 

 determined by consuming it with hydrogen. The first 14 

 samples were analysed by Mr. Svendsen, the remaining 80 

 by myself. The results obtained will be found in Table I. 

 The temperatures in the Table were given by Professor 

 Mohn. When stating the depths from which the samples 

 of water were drawn, regard has not been had to the fact, 

 that the instrument used for collecting them does not close 

 till it has been hauled in about 7 fathoms. The asterisk 

 marking 10 of the determinations signifies that the glass 

 tubes used for preserving these samples of air had small de- 

 fects. To these determinations. however. I have not attached 

 less weight than to the others; for it is impossible to con- 

 ceive that a leakage, after the glass tubes had been exposed 

 for months together to a.difference of pressure amounting 

 to 300'"™— 400""". viz. that existing between the air inside 

 and the atmosphere without. should not have had an ap- 

 preciable effect on the composition of the air they contained. 

 1 Moreover, I hesitate the less to include them as factors 

 when seeking to arrive at general conclusions, since 

 they cannot to auy considerable extent disturb the char- 

 acter of the final results. The volumes are given in 

 cubic centimetres per litre of the sea-water examined, 

 reduced to a temperature of 0° and a pressure of 760""". 



Chem. Sec. Journ. 22, p. 313; 1869. 



