12 FRIDTJOF NANSEN. M.-N. Kl. 
The temperatures taken with the Negretti and Zambra Reversing 
Thermometers are not so accurate. The graduation of the scale of these 
instruments is as usual very rough, and their indications could hardly be 
read off with greater accuracy than + 0'05° C. with the lenses. But in 
the final values there may be still greater errors, owing to possible varia- 
tions of the instrumental errors etc. 
The accidental errors of the salinity determinations as obtained by 
titration are, as a rule, hardly more than + o'or oo. But, as men- 
tioned above, there might in addition be a small constant error, owing to 
the Standard Water used, which is, however, insignificant. In another 
way there may, however, be a more significant error in the salinities. 
For a work which Mr. Helland-Hansen and the present writer are 
now preparing on the “Physical Oceanography of the Norwegian Sea”, 
we have made very accurate determinations of the Specific Gravity and 
the Chlorine of the cold Bottom-Water of the Norwegian Sea, and it 
appears that the salinities computed by Knudsen’s Tables from the chlorine 
may for this kind of water! be between o'or and 0'03 °/oo lower than 
those obtained from the specific gravity. It seems therefore probable that 
the salinities and densities (0,) given in Table II, for Amundsen’s cold deep 
water may be somewhat too low, owing to the deficiency of chlorine in 
this water; e. g. in the case of the salinities from 1700 and 2000 metres 
5 
at Stat. 16, they may probably have been about 34°92 °/oo instead of 34°90 
or 3489 %/00, and the density (0) may probably have been 28'12 instead 
of 28'10. 
In some cases the salinities obtained for the samples of deep water 
are obviously too high. This is, however, not due to inaccuracies of the 
determinations; the cork-stoppers of the glass-bottles have probably not 
been perfectly tight and some slight evaporation has occurred during the 
time between the taking of the sample and the titration. As examples 
may be mentioned the samples from 150 and 250 metres at Station 20 
(July 4, 1901). These samples gave salinities of 34°95 and 35°05 9/00, 
whilst the real value was between 34'91 and 34'92 °/oo to judge from the 
density of the water-strata above and below these depths. The salinities 
obtained give densities (o)) of 28'13 and 28'20, which would make the 
water sink very rapidly; and further, no salinities of such high values 
were observed in any depth at neighbouring stations. 
{ Cf. B. Helland-Hansen and F. Nansen, The Physical Oceanography of the Nor- 
wegian Sea, Report on Norwegian Fishery- and Marine Investigations, vol. II, No. 2. 
