Paafyidningen af Plaskerne, blev der anvendt den største 

 Omhyggelighed, idet disse Operationer enten foregik under 

 Opsigt af Hr. Tornøe, der fra L877 var ansat som Expe- 

 ditionens Kemiker, eller af mig, der i det følgende Aar 

 deltog i Expeditionen. da Hr. Tornøe ikke alene kunde 

 overkomme alle de kemiske Arbeider, som vare nødvendige 

 under Reisen. De af os medbragte Vandprøver ere hen- 

 tede nordenfor den nordlige Polarkreds; de øvrige, der ere 

 tagne støndenfbr denne, ere paa samme Vis indsamlede og 

 opbevarede af Hr. Svendsen, der var Expeditionens Kemi- 

 ker paa dens første Udfiugt i 1876. 



■ Alle de Arbeider, der ere udførte ombord, saasom 

 Luftudkogninger, Bestemmelser af Kulsyren, Klormængden 



og den specifiske Vægt ere senere bearbeidede og diskute- 

 rede af min Yen Hr. Tornøe, der bar overtaget den fysisk- 

 kemiske Del af Arbeidet, medens det for mig stod tilbage 

 at underkaste de medbragte Vandprøver en kemisk Analyse 

 med Hensyn til de øvrige faste Bestanddele. 



Ved disse 1'ndersogelser har jeg nu sat mig ' som 

 Formaal at udfinde. hvorvidt Forholdet mellem Sovandets 

 Bestanddele er udsat for saa store Forandringer, at de 

 lader sig paavise ved de nøiagtigste analytiske Methoder. 

 og om man af de fundne Tal kan uddrage nogen Regel 

 med Hensyn til de mulige Forskjelligheder i Sovandets 

 Sammensa^tning.' I dette Øiemed har jeg udelukkende lagt 

 Vægten paa de af Havets Bestanddele. der. for det første 

 lader sig bestemme med den største Lethed og Sikkerhed. 

 og for det andet — eiter al Erfaring og Sandsynlighed — 

 maa være de- Stoffer, som fortrinsvis kan paavirkes af andre 

 i Havet forekommende Kræfter. Med dette Formaal for 

 Øiet maa man nærmest henvende sin Opmærksomhed paa 

 Kalk. Magnesia. Svovlsyre og Klor. Natron, Kali og de 

 i mindre Mængde forekommende Baser og Syrer har 

 med Hensyn til det foreliggende Spørgsmaal liden eller 

 ingen Interesse, da de ikke kan bestemmes med den nød- 

 vendige Nøiagtighed. Hellerikke kan man for Alkaliernes 

 Vedkommende tænke sig. at de skulde være synderbg af- 

 hængige af fremmede Paavirkninger, uden forsaavidt som 

 en Variation i Klornatrummængden. der jo udgjor den 

 overveiende Del af Havsaltet, vikle være ensbetydende med 

 en tilsvarende Forandring i Våndets Egenvægt. Da der 

 imidlertid er stor Uoverensstemmelse mellem de Tal. der 

 af forskjellige Kemikere er fundne for Kalimængden i Sø- 

 vandet, har jeg for Sammenlignings Skyld bestemt denne 

 Bestanddel i nogle Vandprøver fra forskjellige Punkter af 

 Havet. 



Blandt de Salte, der forekomme i mindre Mængde i 

 Sovandet. har isærdeleshed den kulsure Kalk været Gjen- 

 stand for Kemikernes Opmærksomhed. Mange har bestemt 

 denne Forbindelse ved at koge en vis Portion af Sovandet 

 i længere Tid — under stadig Erstatning af det fordam- 

 pede Vand — og derpaa veie det udskilte Bundfald. Ved 

 at analysere dette har jég imidlertid ikke fundet Spor af 



vised by Captain Wille. R. N. Wben drawing the water 

 and tilling the phials, the greatest care was tåken, these 

 simple but delieate operations having been invariably per- 

 formed in the presence either of Mr. Tornøe (since 1*77 

 chemist to the Expedition) or of myself, who the following 

 year went out as assistant-chemist. Mr. Tornøe not being 

 equal to all the chemical work that liad to be done on the 

 last cruise. The samples of sea-water brought home by us 

 on the return of the Expedition. were all collected north 

 of the Arctic circle: those from the first cruise, in 1876, 

 having been similarly obtained and preserved by Mr. Svend- 

 sen, the. gentleman originally appointed chemist tø the 

 Expedition. 



All chemical work done on board, viz. determinations 

 of air. carbonic acid. chlorine. and specific gravity, has been 

 since. critically revievved and tested by my friend Mr. 

 Tornøe, who undertook to work up the physico-chemical 

 details, while I have analysed the various samples of 

 sea-water with a view to determine their solid constit- 

 uents. 



My object with this investigation. has been to ascer- 

 tain. if possible. whether the relation subsisting between 

 the component parts of sea-water varies sufficiently to aciniit 

 of determining its fluctuations by the most exact analytical 

 methods : and whether. in that case. it were not possible 

 from the results attained to deduce some detinite rule reg- 

 ulating such assumptive differences in the composition of 

 sea-water. To this end. I have exclusivély laid wejght on 

 those constituents of ocean-water which. first, admit of being 

 determined- with the greatest accuracy and facility. and 

 which, secondly. — as is indicated alike by experience and 

 probability, — must be the substances specially acted upon 

 by the forces operating in sea-water. And those substances 

 are chieriv lime. magnesia, sulphuric acid. and chlorine. 

 Snda. potash, and the bases and acids occurring in quan- 

 tities comparatively small. have. as affecting this question. 

 little or no interest. since they cannot be determined with 

 sufticient exactness. Nor is it likely that the proportion 

 of alkalies is dependent in any considerable degree upon 

 extraneous influence. save inasmuch as a variation in the 

 amount of chloride of sodium. which constitutes. we know. 

 by far the greater part of the salts in sea-water. would 

 imply a corresponding change in the specitic gravity of 

 the water. Meanwhile, as the tigures computed by divers 

 chemists for the proportion of potash in sea-water. exhibit 

 a remarkable want of agreement. I have determined that 

 substance in several of the samples of water collected from 

 different parts of the ocean. 



■ Among the salts which sea-water contains in small 

 quantities only. carbonate of lime is that which has most 

 attracted the attention of chemists. Its relative proportion 

 has been repeatedly determined. by boiling for a consider- 

 able time a given quantity of sea-water. — the loss from 

 evaporation being supplied as it arises. — and then weigh- 

 ing the precipitate. On analysing this deposit, ,1 have 



