12 



gjøre Fordring paa nogen Nøiagtighed, viser don ialfald, at 

 Forskjellighederne i Våndets specifiske Vægt i Forening 

 mrd Feilene ved de enkelte Analyser er tilstrekkelige til 

 at forklare de tleste AfVigelser i de fundne Magnesiamæng- 

 der. De Uoverensstemmelser, der ikke kan udtydes paa 

 denne Maade, er (ligesom ved Kalken) saa smaa og uregel- 

 mæssige, at der ikke kan tillegges dem nogen afgjørende 

 Beviskraft. 



Foråt bedømme de Tal. der er fundne for Svovlsyren. 

 maa man tåge de samme Hensyn til Våndets specifiske 

 Vægt som ved Magnesia. Men der maa tillige bemærkes, 

 at Svovlsyrebestémmelserne er i Besiddelse af en langt 

 større Paalideliglied, da Feilene ved de enkelte Analyser, 

 saaledes som Kontrolforsøgene viser neppe overstiger 0.002 

 pCt. De største Afvigelser i de fundne Svovlsyremængder 

 er 0.2160 og 0.2273 pCt. i to Vandprover. hvis specifiske 

 Vægt var 1.0263 og 1.0268. Omend disse Differentser for 

 en Del kan skyldes de tilsvarende Forskjelligheder i Egen- 

 vægten, er de dog for betydelige til. at denne Forklaring 

 kan være tilstrækkelig. Desuden tindes der ogsaa nogle 

 Vandprover af samme specifiske Vægt, der i Svovlsyrege- 

 lialten differerer 0.005—0.006 pCt. hvilket er formeget til 

 at kunne . betragtes som Feil ■ i Analysen. Skjønt dissr 

 Uoverensssemmelser, der kun forekommer paa nogle faa 

 Punkter, er endnu ubetydeligere end ved Magnesia, bliver 

 dr dog vanskeligere at forklare paa Grund af Bestemmel- 

 sernes større Paalideliglied. 



Foråt betragte dette og de foregaaende Spørgsmaal 

 fra forskjellige Sider har jeg i den følgende Tabel opstillet 

 Middeltallene for Kalk. Magnesia. Svovlsyre og Klor i 

 Overfladen, Bunden og de mellemliggende Dyb. Jeg har 

 tillige ildregnet disse Bestanddelen Forhold til hinanden 

 ved at sætte Klor eller Svovlsyre = 100. 



i Iver- 

 fladen. 



Bunden. 



Grjennem- 

 Mellem- snits- • 

 liggende gehalt for 

 Dyb. 'hele 



Havet. 



Middeltal for Cl. . . . 



- Egen vægt 



- CaO . . 



- MgO . . 



- SOs. . . 



CaO: Cl (Cl= 100). . 

 MgO : Cl 



i-Q30 

 1.0265 

 0.0576 

 0.2205 

 0.221 1 

 2.98 

 11.42 



so 3 :Ci: .1.46 



CaO : SO, (SO S = L00) 26.05 



MgO:S0 3 99.73 



1-933 



1.0265 



0.0581 



0.2207 



0.2208 



3.01 



1 1.42 



1 1.42 



26.32 



99-95 



1-934 



1.0266 



0.0577 



0.2200 



0.2223 



2.98 



u-37 

 11.49 



25-95 

 98.96 



1-932 



1.0265 



0.0578 



0.2203 



0.2214 



2.99 



1 1.40 



1 1.46 



26.1 1 



99-55 



Som der vil sits af den sidste Tabel. afviger Middel- 

 tallene for Kalk og Magnesia saa yderst ubetydelig fra hin- 

 anden, at disse Variationer ganske kan s;rttcs ad al' Be- 

 tragtning. 



with 110 pretensions to accuracy. will at all e vents show, 

 that differences in specitic gravity and errors of analysis 

 generally suffice to account for the want of agreement in 

 the computed amounts of magnesia : and when. as is the 

 case with the lime. this cannot be so explained. the varia- 

 tion is alike too slight and too havgula r to admit of its 

 possessing any real demonstrative power. 



Wh en estimating the accuracy of the figures found 

 for the sulphuric acid. no less regard must be bad to the 

 specitic gravity of the water than with magnesia. It must 

 also. however. be home in miiid. that the sulphuric acid 

 determinations are distinguished by a far higher degree of 

 accuracy, the errors of analysis scarcely exceeding 0.OO2 

 per cent.- The most considerable differences in the results 

 for sulphuric acid — computed from two samples of water, 

 specitic gravity respectively 1.0263 and 1.0268 — amount 

 to H.2160 and 0.2273 per cent. True. this diversity can 

 be partly ascribed to a corresponding deviation in specitic 

 gravity; but they åre much too considerable to be tbus 

 accounted for. Besides. some of the samples with the 

 same specitic gravity differ iii their proportion of sulphuric 

 acid to the extent of 0.005, or 0.006 per cent, — too con- 

 siderably, therefore. for the discrepancy to be regarded as 

 a mere error of analysis. This want of agreement, 1 though 

 referring to water from a few localities only, and less 

 considerable even than that in magnesia, is nevertheless 

 difticult. to explain, by reason of the greater accuracy of 

 the determinations. 



With a view to the hetter apprehension of this and 

 the foregoing questions, I have tabulated the mean amounts 

 of lime. magnesia, sulphuric acid, and chlorine in water from 

 the surfa.ce, from intermediate depths. and from the bot- 

 tom. I have likewise estimated the relative proportion of 

 tbese compounds, with 100 equivalents of chlorine or sul- 

 phuric acid as the standard of computation. 



S urface, 



Bottom. 



Inter. 



Depths. 



Mean 

 Vahie. 



Mean Yalue Chlorine 1.930 



„ ,, Sp. Gravity 1.0265 



„ CaO . . 0.0576 



,, MgO . . 0.2205 



„ SO a . . . 0.22 1 1 



CaO: Cl (Cl =100). . 2.98 



MgO: Cl 11.42 



S0 3 :C1 11.46 



CaO: S(), (S0 3 = 100) 26.05 



MgO: SO :t 99-73 



1-933 

 1.0265 

 0.0581 

 0.2207 

 ! 0.2208 

 3-oi 



1 1.42 



1 1.42 



26.32 



99-95 



1-934 



1.0266 



0.0577 



0.2200 



0.2223 



2.98 



n-37 



11.40 



25-95 



98.96 



1-932 



1.0265 



0.0578 



0.2203 



0.22 14 



2.99 



1 1.40 



1 1.46 



26.1 1 



99-55 



As appears Ironi the Table, the mean valnes for lime 

 and magnesia vary so inconsidcrably inter sv that we may 

 safely disregard these differences. 



